This thread will be a work in progress for the next few days, weeks or even months. The original idea was to have a place to send people when they asked basic questions about where various sensors are in the top system. That soon turned into a thread that discussed troubleshooting more than I intended - but I think it's a good idea.

The questions keep coming, and it's getting tiring answering the same questions over and over again. The purpose of this thread is to provide PHOTOGRAPHIC documentation of where the sensors are and some background on what they do and how you can troubleshoot things yourself. It is hoped this thread can serve as a place to send new owners (or those who have never had to address these issues before) so they have an idea of where to look when issues arise. This thread does not take the place of the (horribly complex, incomplete and sometimes inaccurate) service manual; instead, my intent here is to produce an easier-to-read guide to your convertible top. This thread won't answer all questions, but it is hoped it WILL give you enough information that you understand the system well enough that you can actually find and fix some of the issues we all have with our convertible tops. Many are surprised to find they they, themselves, can resolve some issues on their own, at home. Issues with the divider switch, loss of sync and a few others can be resolved by ANY owner.

You CAN NOT make use of this thread in most cases without reading thru the first ten posts thoroughly. And I'm sure no one can read it once and 'get it all', I tried to make this as concise as possible, but I"m also not writing a book here, so some effort on the reader's part is certainly necessary. If it is hard to read, well, you paid nothing for this, and I got paid the same!

I struggled with format here:
1) Do I simply explain where all the sensors are, then explain how they interact?
2) Or do I present each sensor as I explain the sequence of operations?

After a lot of thought, I went with option 2. When we get started (in post #2), we will assume the top is up and latched and you want to put the top down.

Some definitions before we proceed:
BCM - Body Control Module
PTCM - Power Top Control Module

These two modules will come up often in the following discussion.

The BCM handles a lot of functions with the car OTHER than running the engine, as running the engine is the chore of the ECU/PCM (engine control unit/powertrain control module). The PTCM interacts with the BCM a lot, as you will soon understand. The BCM is in that big box next to the battery, the "Control Module Box", under the hood on the passenger's side. If you open the box, you will see three large modules standing on edge, with many wires plugging into them. In the photo below, the battery is barely visible at the bottom of the photo, and the cover has been removed from the box.




The PTCM is hidden behind the trunk trim panel on the driver's side. It is bolted to the hydraulic pump/valve assembly which it controls in order to run the system that moves the top.
The yellow box gives you the approximate location of the PTCM, again, the pump/valve mechanism is right behind it.



Robert McCubbin offers this photo of the PTCM, with the trunk trim panels removed. The PTCM is the black module, item number 1.
Behind the PTCM is the Power Top Hydraulic Assembly, item 2, (which contains the pump motor, solenoids and valves that send pressurized fluid to the cylinders as needed).
Also shown is a very good photo of the divider switch (item 3, we will be talking a LOT about that switch).




Keep checking back here, to this FIRST post, as I will document revisions and contributions from others as the thread takes on a life of it's own. There is no way I can think of every detail that is involved here - YOU can post here to add stuff or send it to me via PM email or on Facebook and if possible, I will put it in the first ten posts - contributions will be credited below and inline.

PLEASE be PATIENT, this thread won't be "ready for use" until maybe the second week of August!


REVISION HISTORY
Contributor - Date - Changes/additions made - Post Number(s)
Mark/Pizza - 08022020 - Added photos of BCM and PTCM - Post 1
Bob/bmccubbin - 08022020 - Added photo of trunk items - Post 1
Mark-Pizza - 08232020 - Replaced photo of modules showing correct positions of the BCM and ECU. - Post 1

 

The Latch Retainer Switch

Buried in the windshield frame, above the passenger's sun visor, is the Latch Retainer Switch. If you want to put the top down, this switch gets the process started.

So, as I said before, the top is up and you want to put it down. You first turn the "D" ring and press the top away from the windshield frame. When the top is latched to the frame of the windshield, those hooks you see in the photos below are grabbing the frame and the one on the passenger side is pressing on the "Latch Retainer Switch". One side of the switch is grounded, the other side of the switch has a wire on it that runs to C1 Pin 16 of the PTCM in the trunk. When you turn the handle, the hooks retract and the latch retainer switch relaxes and removes the ground from the wire running to the PTCM. The PTCM sees this, and sends messages to the Body Control Module that cause the BCM to lower the windows. While that is all there is to the operation of this switch, at this point, you can potentially confirm a lot of things about the performance of the electronics of the car affecting top operation.

If you turn the "D" handle and the windows go down, you know that:
1) The Latch Retainer Switch is good.
2) The BCM is getting CAN BUS messages from the PTCM.
3) The PTCM is healthy and probably not the cause of what ever problem you are having with the top.

Take note of these very important points:

• You will notice the light in the top switch is now on. This is the PTCM's way of telling you that "the cycle has started". This means that the PTCM considers the sequence of moving the top to have started, and....
• If you move the car over 9 mph, the light will blink over and over and you will hear a beep. This is the PTCM trying to warn you that you are doing something it considers to be a BAD IDEA.
• These two points should be kept in mind, this is INFORMATION being provided to you that, someday, may be important! (Keep reading, I'll get you there.)

You now have all the information you need to determine if the Latch Retainer Switch is working.

The Latch Retainer Switch is in that cavity where the top's hook goes to clamp the top to the windshield frame.


Here is a closer look. I've drawn the metal leaf of the switch in it's approximate location. Try sticking a finger in there to feel it.

 

The Divider Switch

In the trunk, you have a divider that you can put up to "reserve" space in the trunk for the convertible top to store in while it's down. It would be a bad day to put the top down when there was anything in the way of the top's travel. To stop you from putting the top down in such cases, there is a switch in the trunk that tells the PTCM that the divider is up. If that switch does not indicate the divider is in position, the top won't go down. (Not a bad idea, but unfortunately, probably the most common failure of the top system is the failure of either the divider switch OR, failure of the divider rod to properly activate the switch!)

Here is a look at where the switch is, the arrow points to the switch, but the switch is not visible in this photograph.



Here you can see PART of the switch. Note the shiny metal leaf, the rod from the divider has to press, essentially, UP on that leaf in the direction of that big round trim plug. The little white '****" you see above the leaf is the button that the leaf presses on. When that little button is pressed, the divider switch is 'active' or 'closed'. Can you now see why the divider switch can easily fail to indicate that the divider is up? (If you missed it, there is a very good photo of the divider switch in post 1, at the very bottom of the post, with all the trim panels removed.)

There is much more to learn about this switch, but first, we must talk about another switch.

 

Roof Open Switch

I've found this one referred to in the service documents as the "Roof Open Switch" and as the "Top Open Switch". Describing where this switch is seems to be almost impossible. We tell people it's "over the passenger's head" and that's close - but it really IS hard to see when the top is up. (It's impossible to see when the top is down, as the top is buried in the trunk!) But a simple picture will fix that.
Let me show you the switch and then I will explain why it exists.


In this photo, the top is partway down, if you just pop the top from the frame with the "D" handle, it is almost impossible to see - but now you know where to look!


Here is a closer look. The arrow points to the switch. Note that there is a 'hanging down thing'. This is the switch in the relaxed position. That 'thing' is called a 'cam'. When the top is pulled down and the "D" handle is rotated to clamp the top to the windshield frame, that cam is pressed up and the little button on the switch is pressed.



Here, I am pressing on the cam so it is now positioned like it would be if you had the top up, closed and latched. Note how the arrow is pointing to the little white button on the switch and it is pressed.


Now you know where the divider and top open switches are. Let's now see what they do, and how to determine if they are working right.

 

The Issue of the Divider and Top Open Switches

The Background:
Let's think about what we've done so far. The top is up, we have turned the "D" latch and pushed the top up and away from the windshield frame. In doing so, the 'top open switch' is now relaxed. The divider is up in the trunk and we are about to hit the button to start the pump and get the top moving.

1) If we were to hit the button and the pump starts, the divider better be up, so that we know nothing is in the way of the top as it goes down into the trunk area.
2) And if the pump starts, the top BETTER be released from the windshield frame. If you start the pump with the top still attached to the windshield frame, you will do damage to the system. Cylinders may break, hydraulic lines may burst, or the pump/motor may be overloaded and fail.
The divider and top open switches are there to STOP these bad things from happening.

The divider and top open switches are wired in series. When the top open switch is relaxed, it closes. When the divider is up and pressing on the divider switch, that switch is also closed. With these two switches closed, they provide a ground signal to C1 pin 7 on the PTCM. THIS SIGNAL is what 'tells' the PTCM that it is safe to start the pump.

The Frontground:
Ok, so you turn the "D" latch and push the top up. You hit the button. IF the top open switch and divider switches are both closed, you might think the pump will start. It will. But several things happen first, and they all happen in under two seconds.

If you have turned the "D" handle and pushed the top away from the windshield frame, when you hit the button the first four things below happen in the short time before you hear the bow latch "SNAP" and things start happening:
1) The PTCM checks with the BCM to see if you are driving over 9mph, if you aren't it continues...
2) The PTCM checks with the BCM to see if the spoiler is either in the fully down position OR in the fully extended position, if it is, it continues...
3) The PTCM checks with the BCM to see if the trunk is fully closed, if so, it continues... (The sensor that tells the PTCM if the trunk is fully closed is discussed in post 6.)
4) The PTCM commands an electric lock in the trunk lid to activate (locking the trunk for the duration of the top cycle) and expects to see an indication that it is locked. If it gets that indication, it continues...
5) The pump starts and the bow latch is released, and we are on our way.

But back to the divider and top open switches. What if the divider moves slightly and no longer presses on the switch enough to activate it? Well, the top may stop moving in the middle of it's travel. Or it may keep moving. You see, as the top goes down, after a certain point, the PTCM ignores the top open and divider switches. Look at the next photo, as the top does down, in the approximate position shown, the PTCM ignores these two switches after this point. (Think about it, there is no reason to keep watching these switches; we KNOW by now the top is unlatched and the divider is up - otherwise we'd not have started the pump.)

There is NO indication the PTCM has started to ignore "the two switches", I had to test and test to see where it no longer mattered. Once the top gets about to THIS point, the PTCM starts to ignore the top open and divider switches:



But What About Putting The Top Up?

So, you are driving along and it starts to rain. You pull over and put the top up. The LAST thing you want, is for the top to refuse to move. The designers thought of this (or at least it seems they did). If the top is down and you hit the button, the PTCM does not look at the top open or divider switches. (Again, there is really no reason to.) As the top rises, when it gets just about to the point shown in the photo above, it DOES start looking at the two switches. IF the PTCM finds that either of the two switches is not closed, it will beep at you - but the top will continue to keep going up. If you stop and try to lower the top, it will beep and refuse to move, but if you THEN press the "UP" part of the button, it will continue to go up. Again, the designers were thinking here.

This is important - if you have a top that won't go down, try putting it down manually (see post 9). Then, try raising it. If it goes UP but not DOWN, it is reasonable to assume the issue is the top open switch OR the divider switch. And we already know that if there is a problem with EITHER of these two switches, it is almost ALWAYS the divider switch.


I Don't Need This Crap - I'm Going To Bypass Those Switches

Many of us have bypassed the divider switch. Yes, we MUST be careful to always make sure the divider is up, or AT LEAST that nothing is in the way of the top.
But I would NEVER bypass the top open switch. Doing so would mean that, if you hit the switch by accident, the top motor MIGHT start - and that is a threat to the entire system, as I described before. DO NOT bypass the top open switch.

 

Truck Closed Sensor

Buried in the trunk latch mechanism is the sensor that gives indication that the trunk lid is fully closed. I've never found this sensor in the wiring diagrams nor in the pictorial diagrams, but Wayne Mullins in Wilmington found his top would simply not move one day, and he proved the issue was this sensor. I also had an issue once where I had the trunk somehow locked, but it was not fully closed. By pressing down hard on the lid, with a helper pressing the button, we got my top to move!

 

Electric Trunk Lock

All of the locks in the Crossfire are pneumatic. That is, they operate on air. The central locking pump puts either pressure of vacuum into the hoses going to each lock - depending on whether you wish to lock or unlock.

There is an exception to this rule: The Roadsters have a second lock on the trunk lid, this second lock is electric and is operated ONLY by the PTCM. The designers wanted to be sure no one can open the trunk lid while you are moving the top up or down - as this would mean the spoiler or trunk lid might hit the tonneau lid.

The electric lock is located in the trunk lid, bolted in place near the latch. . In the thread "Trunk Lid Jammed", you can read the saga of how this lock fouled up one of my Sunday afternoons many years ago.
The yellow box gives an approximate location:



Problems with the Electric Lock
One of the issues with this lock, is that when the PTCM tells it to "unlock", it will unlock part way, that is, the cam won't move all the way such that the truck stays locked - but the electric travel switches in the lock tell the PTCM that it DID unlock!
One way around this is to disable the lock. Now, you can't simply remove this lock, as the PTCM MUST see indication that it locked. So, what we do is we removed the trim panel from the underside of the trunklid, we then remove the two screws holding this lock in, and we remove the vanilla colored "cam" from the end of the lock mechanism. This way, the cam can move back and forth without actually locking the trunk - and yet, the PTCM thinks all is normal. This "electric trunk lock disable mod" is a highly recommended mod for your next 'tech day'.

Here is the lock mechanism with the offending "cam" circled in red. It snaps off the end of the actuator arm with ease.


Here is the mounting location of the electric trunk lock (yellow arrow) with the two mounting screws (red arrows):



Which Lock has me locked out?
So, you try to open your trunk but you can't, it is locked. How do you know which lock has you locked out? This is easy, when you try to open the trunk, the lever will either refuse to move or be "floppy". This is what tells you which lock has you locked out.

Lever is "Floppy" - It appears the lever is now disconnected from anything, like something is broken inside. But nothing is broken - the pneumatic locking system has you locked out. Try using the button on the dash or the buttons on the key fob, press "Lock" and then "Unlock" again to see if it works.

Lever is "stiff" - It appears the lever is now jammed or something. This is an indication that the electric lock has you locked out. This is when you should remember that the LAST thing the controller does at the end of a cycle is to unlock the trunk. If you let go of the button BEFORE you got a 'beep' when putting the top up OR down, the lock will probably still be locked. Try pressing the button again and see if you can get a "beep". Or, put the top up or down and make sure you wait for a beep - this may clear it.

 

Spoiler Position

On Base/Limited/SE models, the electric wing can cause issues with top operation. The BCM knows (or thinks it knows) the position of the wing at all times. If you try to put the top up or down when the wing is not EITHER fully UP or fully DOWN, the BCM will tell the PTCM to NOT move the top. You will get a blinking light and a 'beep'. MOST of the time, the wing will actually be in a valid position, but for what ever reason, the BCM has lost track of what is going on with the wing. This can (apparently) be caused by such things as a weak battery, bad spoiler travel sensor, or water intrusion in the area around the wing motor (which causes a bad spoiler travel sensor). I call this "a loss of sync(ronization) between the wing and the BCM."

In some cases, shutting off the engine and yanking the battery ground cable off for a few seconds will reset the BCM's logic and fix this. It is very hard to KNOW that this is the issue, unless you take the car to someone with a STAR diagnostic computer - a rare item these days.

 

Loss of Sync

I mentioned "a loss of sync" above, when discussing the BCM's operation of the spoiler. But there is a much more important "loss of sync" that happens, and it happens a LOT.

Consider the complexities of the top system: the system of hydraulic cylinders, the sensors on those cylinders (which we have not even mentioned), combined with the switches/sensors we HAVE mentioned - along with the interactions with the BCM. All of this comprises a very complex system. In some cases, the PTCM can loose track of where in the process it is; in such cases, if the PTCM continues to command cylinders to travel without knowing for sure where things are, damage can be done to parts of the car.

This is why our tops so often will suddenly refuse to move. The PTCM has lost track of things and is 'afraid' to move ANYTHING. At this point, it sucks to be you or I. This is why it is VERY important to know how to put the top up and down manually. It is also important that we all have our 'top tool' in the glove box or console. If that tool is the original one that came with the car, we must also have a 6mm hex key wrench. With these tools and some knowledge, we can put the top up or down manually.

But what do we do about a loss of sync? And what do we do when the top starts moving, then DEAD stops and won't let us do anything? Let's answer these questions in reverse order.


Releasing Pressure and Moving the Top Manually

If the top stops dead, you must release pressure and then move it manually. The owner's manual tells you how to press the top button to make pressure release, but I have had problems making that technique work. I have my own trick - I pull the PTCM fuse. This works because the 'relaxed state' of all the relays is to open and let all pressure out, and fluid flows back to the tank.

The fuse in most Crossfires is fuse 5 in the underhood box. It will be labeled "Roof Control Unit" and will be a 25 amp fuse (52 amp if you are looking at it upside down!)
I have it circled in yellow below, and again, I THINK they left this in position 5 for the entire production run, I just don't know that for sure.



I posted a youtube video on how to put the top up and down manually, it is here:

But Klaus at "TopHydraulics" produced a better one (I have not watched it all, but I know the guy and I'm sure he did better than I did):



How Do We Get "SYNC" Back?

Once you put the top up or down manually, you may find the switch now works and things are fine. If not, you may need to "teach" the system where things are. I've had to do this a few times in the eleven years I've owned three roasters. The procedure that works for me is simple.

1) Start the engine.
2) If you have not released pressure (that is, if things refuse to move when you try to move the top parts), pull fuse 25 for a few seconds. THEN, be sure to put it back in before proceeding.
3) Manually raise or lower (depending on what position the top is currently in) completely, including locking the bow with the hex key (that both I and Klaus talk about).
4) Now, if you raised it, lower it completely. If you lowered it, raise it completely.

Once you are done, try the button. If it still won't work, with the engine running, do 3) and 4) maybe a total of two or three complete cycles. It is important to have the system "awake", that is why you have the engine running, so the PTCM is powered up and watching what you are doing. I've had at least four or five times in eleven years where the top won't work, or it stops mid-cycle - every time, this got me going. Others have reported similar results, including one guy that had paid a dealer to "diagnose" the system, he got the car back with the top not working still. This technique got it going.

 

Prevention and Other Stuff

Always have the engine running when moving the top up or down.
Why? First, heavy motors like the pump unit do not like low voltage and are not designed to run on low voltage. Second, fluid flow rates are somewhat important, a slow running pump means slower flow rates.

But the above are almost theoretical reasons. I have a PRACTICAL experience that make me sure my rule is a good idea. I've owned three Roadsters, never had any real issues with the top operation to speak of; always used my "engine running" rule like a religion. BUT, with my current SE, one evening, I went out to put the top up. But I was lazy, didn't want to get in and push the clutch, etc. So I just turned the key on (with a five year old generic battery) and hit the button. The tonneau lid raised about four inches, the pump stopped and I got a fast bee-beep and flashing light. I cycled the ignition switch, nothing worked. Had to put top up manually (after pulling fuse 25).

The next morning, I started the engine, but the top would not move. I did the "up and down manually" thing twice and it was happy. BUT, I have a seatbelt light now. My seatbelt module had been damaged by the spike coming off the motor (I suppose). I blame a swinging low voltage off the old battery, since the alternator was not there to keep things above 13 volts or so.

It is up to you what YOU do, but I believe in running the engine when moving the top.


Use The Top System Often
Some people avoid moving the top because they want to "save" the hydraulic system. I think lack of use is worse than use. My Graphite was my daily for five years. I drove it year around in the south. I HAD to have put the top up and down at least 550 times (and probably twice that) in those years. Again, that was was never an issue for me.

 

The hanging box is the PTCM

The hanging box is the PTCM. The bracket above and to the left of the box is the bracket for it. One screw holds it in place.
. The bracket above and to the left of the box is the bracket for it. One screw holds it in place.

I watched Klaus at TopHydraulics YouTube video, and found it extremely helpful in understanding how everything works together.

 

I had the positions of the BCM and ECU wrong in the very first photo in post 1.
This has been corrected as of the last few minutes.

 

Super new Crossfire owner (48 hours) and came across this thread. Previous two owners dating back to 2013 have been opening and closing the top manually. I spent two hours reading here and the top is now fully functionable!! Couple resets and up downs and it's working as it did in 2005. Also found a receipt for $550 diagnostic bill with a recommendation for replacing the PTCM(Obviously Unnecessary). Thank you Pizzaguy and other forum members.

 

This is almost funny, but it's not, is it?

 

I have been having " top won't go down " for 2 months. Yesterday I found this sensor and just push it in and out a couple of times. Then I did the manual up/down
on the top ( car always running) . So, don't really know what fixed it but now my top works fine. Thanks to Pizza man and everyone else for your help : )

 

Here is a contribution from 'srt6-xifre'; David. It is his offering of how to replace the Latch Retainer Switch.

 

Which sensor did you push in/out?

 

Does anyone know where I could purchase the left bracket and microswitch for the trunk divider panel? I purchased a used 2005 Crossfire convertible, and it had been previously in an accident (left rear). Apparently when it was repaired, the left bracket was not installed. The panel only rests on the right bracket, and moves out of place easily. I would really appreciate any advice on where to acquire one. They are no longer available to purchase new. Thank you.

 

There is a guy on Facebook that is trying to "print" a replacement bracket. Not sure where he's getting the switch, but that is just a generic microswitch, not impossible to find.
If I can turn up his post I will link to it here.

 

A guy on here was printing them, photos as well.