Door switch on console switch group
 

I wonder if anyone can help me please.
On the console there is a switch to lock or unlock the doors and hatch. My one failed at some time, I installed a new radio some time back but I do not think I buggered it up then. I tried a used BCM every thing worked as it had before, still no luck with the switch, so I left the BCM in place. The original is now a spare.
When I check the circuits all is fine, the resistor gives two Ohm readings 0 and another which I have forgot, I have two spare switches and they read the same. The switch is on the right side of the emergency flasher with another one on the left side. They make up a three switch module.
My problem is that I can get no power to the switch, and I have no idea where it should come from. I am out of my depth when it comes to reading the schematics. The twisted pair in the circuit going to he CLP/SSM have the colours wrong.
My question is does anyone know where the power comes from my best guess is the splice block 200. I just want to be sure.
Thanks in advance for any help.

Re: Door switch on console switch group
 

If I'm reading this right, the WT/DG wire on the door lock switch comes directly from the BCM and when the switch is activated, it connects to GND at G200. So if you can ground the WT/DG wire, the door locks should unlock. There is a resistor in the switch that changes the resistance to ground for the lock function. look at page 8w61-4 on the service manual to see the switch circuit. This should help you diagnose whether it is the BCM or a bad switch. Hope this helps.

Re: Door switch on console switch group
 

Thanks for the reply, the switch and the BCM are fine. I tested the switch with a bulb and a multimeter the resistor is fine. I switched BCMs and they both function identically. My problem is there is no power in the switch circuit and therefore the locks cannot be operated using the console switch.
The ground is obvious and checks out OK, but the power is not there.

Re: Door switch on console switch group
 

There is no power there to test. The switch just provides a ground path from the BCM. Check wiring by grounding the WT/DG wire at the switch terminal. Could be a broken wire between the switch and the BCM

Re: Door switch on console switch group
 

This may take some time as I will have to strip the console to get at the wire at the switch. I had it in and out three times in the last week and it is a pain to do.
A break in that wire is a definite possibility as I cut that wire when I installed my 1st Double DIN head unit so it could be extended to the arm rest area. Subsequently I went to a different design and the switch module went back to the area that once had the ash tray. I cannot say when that switch failed to work as it is not used very much at all. The wire joint is soldered and shrink wrapped, did I make a bad joint? I am not a first timer at soldering so I doubt it. I have not seen any signs of rodents.
The easiest way is to find the wire on the other side of the switch and test it with a light and check the continuity between the WT/DG at the BCM through the switch to the line entering the switch, operating the switch should vary the brightness of the bulb. That wire is hard to find for me and maybe it is not safe to do as it is a ground wire.
Thanks for the time and effort you have spent, I appreciate it.
I guess I am going to have to bite the bullet and pull the radio again.:(

Re: Door switch on console switch group
 

Just a quick note, the LED in the switch is lit so there is power at the switch.
I have found that the twisted pair in the circuit is not the colours noted on the schematic.
This makes me wonder if the yellow/green wire is correctly identified.

Re: Door switch on console switch group
 

That LED is fed from the interior lights circuit and is not a power indicator for the switch.

Re: Door switch on console switch group
 

Here is how it works:
As Wayne said, the light in the switch is powered by the ICM, it's not part of the actual circuit involved in locking or unlocking the doors, tho it does share a ground with the switch, so if the backlight comes on, we can probably assume that pin 4 has a good ground.

With the button at rest, there will be voltage on pin 8. I don't know if this would be 5 volts, 8 volts or battery voltage of 12-15 but I'd bet it is 5 volts.
When you UNLOCK this voltage must go to ground, that is, zero or very near zero. This tells the BCM you pressed UNLOCK.
When you press LOCK, the voltage at pin 8 drops from (what I think is, again, 5 volts) to some value lower, probably about 2.5 volts. THis is due to the resistor.
This tells the BCM you want to lock the doors.

So, do you have voltage at the BCM? If not, cut the wire. Do you have voltage now? If so, the line to the switch is shorted to ground somewhere, or the switch is in UNLOCK constantly, grounding the line.
If you have voltage at the BCM but not the switch, then the wire from BCM to switch is open somewhere.

I'd measure the voltage at the BCM connector C3, pin 49. See what happens to the voltage when you press LOCK and UNLOCK. You should get the results I gave you above.

If pin 49 is at zero all the time, the wire may be nicked and shorted to ground somewhere.
If pin 49 has voltage and it never changes when you press the button, the wire may cut somewhere.

IN all cases, make sure your meter is grounded well, so you can trust the readings. I like to connect my meter ground first, then measure some known point, like the battery positive terminal, if I see my 12-14 volts of battery, I know I"m good to proceed.
https://cimg3.ibsrv.net/gimg/www.cro...01546fb7a3.png

Re: Door switch on console switch group
 

Thanks for your response, I have just seen and I will try what you say and get back to you.

Re: Door switch on console switch group
 

I tested the resistance of the switch resistor and found it to be 200 Ohm, does that seem correct? That is between pins #4 and #8 with the switch in the door unlock position. The reading in the door lock position is 00000.

Re: Door switch on console switch group
 

What is the reading when the switch is in its normal position? Should be infinity, with switch in the unlock position it should be 0, with it in the lock position 200 sounds about right.

Re: Door switch on console switch group
 

Normal position says Auto.
Unlock position says 000000.
So I guess that is OK.
Thanks for the reply.

Re: Door switch on console switch group
 

with the ignition switch in the run position and the doors closed and locked, momentarily ground pin 8. You should hear a slight click and/or see the lock plunger move upward. If not, you have an open circuit (broken/cut wire) between the BCM and pin 8

Re: Door switch on console switch group
 

Nothing happens when I do this. Looks like a broken connection.

The voltage on pin #49 is 12 volts, it stays the same when locking and unlocking.
I put in a spare BCM when this issue was found with no change, I have also changed the switch module also with no change. The switch it self seems to work OK as mentioned.
I am going to pull the head unit and test the wire. This is a time consuming job as the head unit has a frame that has to be removed as well.
I pulled the head and tested the yellow/green wire, 12 volts the same as at the BCM.
The twisted pair, DG (-) and WT (+) have a constant 12 volts on them these go to the CLP/SSM.
I am getting nowhere and I give up for now. I have no idea when this failed, it could have been years ago .

Re: Door switch on console switch group
 

Well six weeks or so has gone by and still this problem niggles me, I hate to be bested by some problem that probably has a simple answer. Mind you the problem maybe that I am missing the obvious cause. It is the only thing that does not work on the car besides the tire pressure sensors.
After all the time spent on help by pizzaguy and Shamrock, my thanks to them, I think that I owe it to them to solve the riddle.
Maybe I will have to look at the CLP/SSM which I dread as there is a lot of work involved in doing so. Taking out the radio and removing the radio/AC bezel is a big enough job.
Watch this space as all the steps will be put here with the voltages on the various circuits.
Update
I tested the voltages on two circuits.
There was no change in the Voltage in the circuits with the ignition ON or OFF.
Initially the 1.5 Volts was 5 Volts but went to 1.5 Volts after a few seconds.
I could not find the ground to the resistor so the switch was not tested although when the radio was out of the dash I measured the resistance and got 200 Ohms.
I feel no closer to finding the problem.:(

https://cimg3.ibsrv.net/gimg/www.cro...b591c9c136.jpg

UPDATE #2
The rear face of the emergency flasher module.
The Ohm reading is taken between Pins #4 and #8.
When the button is pressed to the OPEN position the meter reads 200 Ohms.
When the button is pressed to the CLOSE position the meter reads 0 Ohms.
Now I have to find the ground for Pin #4 or take out the radio face plate.

https://cimg6.ibsrv.net/gimg/www.cro...2e1c00ccbf.jpg

Re: Door switch on console switch group
 

See Update to above post

Re: Door switch on console switch group
 

So you have 12 volts or so at pin 49? ANd this NEVER changes? But you measured the switch from pins 4 and 8 as:

No push - infinite
Push to Lock - 200 ohms
Pust to Unlock - 0 ohms

THAT is correct. So, when you press "Unlock" the voltage HAS to go to zero. If it does not, then, since the switch is good, either the connection from pin 49 to switch pin 8 is open or the wire from switch pin to ground is open.
THat is all it can be. In fact, I would like to know, if you press the button for Unlock and see full voltage at pin 8, if you can, probe pin 4. If it is full volts, that proves the ground wire is the issue. (Not sure how easy it is to get to.)

Remember, ground is 0 volts, when you press unlock, you connect pin 49 to ground and it MUST go to zero volts, if it does not, you are not really connecting it to ground.

Look for pin connections from switch to wire that LOOK like they are mating but aren't. Look for 12 volts on the ground wire when you press Unlock, there should NEVER be 12 volts on that wire cause it goes to ground.

The other pins from CLP/SSM are fine, that voltage changes when modules go to sleep. This is all about getting pin 49 to go to ground/zero volts on Unlock. THat is the 'Acid test". UNLOCK iS GROUND.

Re: Door switch on console switch group
 

Re: Door switch on console switch group
 

I have never seen the back of that module until now. :)

Re: Door switch on console switch group
 

This module un-clips from the bank of switches, the seat heater switches stay with the main body, the other switches all snap into the main body. The main body is quite complicated.