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Troubleshooting & Technical Questions & ModificationsHave technical or modification questions about the Crossfire?
Find out the answer, or give advice in here!
Heater Valve Repair Kit worked great. Specifically, it solved my problem of the system blowing hot air even when the temperature controls were set to max cold. Heat temperature settings worked fine, as did A/C. However, I just got hot air when all I wanted was outside air blown through the vents.
A few notes for others who will undertake this repair:
1) The old washers and gasket looked ok, but they clearly were worn after twenty years.
2) The repair kit includes extra parts not needed in the M-B/Crossfire heat valve. AMHIK. I have "X"-ed them out in the image.
The heater valve is easily accessible from the top of of the engine when standing by the passenger fender. Extending the hood support strut to its full length prevents one's head from hitting the hood.
The heater valve need not be removed. Use a Torx T10 to remove 5 screws for disassembly.
I completed the fix yesterday, using the Klifex repair kit. During the disassembly, I found one of the brass coned plunger's stems broken in half. I was able to remove both pieces with needle nosed pliers, with no issues. I did use a magnetic screwdriver assuring me the 5 attaching torx screws were not lost. It was a fairly simple procedure.
Thanks for this thread.... Dennis
DTMenace
I completed the fix yesterday, using the Klifex repair kit. During the disassembly, I found one of the brass plunger's stems broken in half. I was able to remove both pieces with needle nosed pliers, with no issues. I did use a magnetic screwdriver assuring me the 5 attaching torx screws were not lost. It was a fairly simple procedure.
Thanks for this thread.... Dennis
DTMenace
WOW, glad you found that. Strange, was there oxidation/corrosion on the stem where it failed? Strange it just 'broke in two'.
WOW, glad you found that. Strange, was there oxidation/corrosion on the stem where it failed? Strange it just 'broke in two'.
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GraphiteGhost
When I removed the top cylinders and the two silver plungers, I used a flashlight to look down into the fluid filled passage for the brass coned plungers. I could see the tip of one, but the other was not visible, it was broken off and laying sideways. After pulling the two parts from the receptacle with needle nose pliers, the part had a clean break and straight, no bends in the shaft. I believe this happened at the time of the original assembly time by the supplier/vendor and just passed it along to Karmann for installation into my SRT6.
When I installed the new parts, I made sure the brass and silver plungers fit properly before I installed the top cylinder covers to complete the job. There wasn't any oxidation/corrosion on the old parts.
Just a heads-up to anyone doing this repair, make sure the brass plungers are whole before installing the new parts.
Regards, Dennis
DTMenace
Last edited by DTMenace; Apr 18, 2024 at 05:16 PM.
The first thing you must do, is realize this is likely not a problem with the A/C at all. A/C issues are EXPENSIVE to fix, so do not make it one until you KNOW it is the A/C. If the coolant control valve (the duovalve) is fully open, then anytime the engine is warm, you will get warm air even if the A/C is fine. The duovalve's default is wide open. If any wiring or connector corrodes or the fuse blows, you get full time hot air, period. So, is the A/C broke or is the heater coming on all the damn time? Which are we chasing? THere is an easy way to tell.
How I would go about this:
Start car, turn both climate control temperature ***** "fully blue", that is, to the coldest setting. This commands the duovalve to close.
Warm car to operating temperature (needed to almost 9am on the temp gauge).
Turn fan to high and check - with A/C off and ***** "full blue", you should have air from the vents essentially at ambient temperature, maybe a little warm but NOT HOT. Check all four vents.
If two on one side are OK, but the two on the other side are hot, your Duovavle is stuck open on one side. (Easy fix)
If all four are blowing hot, the duovalve is open on both sides; this is not a stuck valve but either a failure in the controller or a "no power to the duovalve" issue. (Potentially an easy fix)
If things work and you get no really HOT air, then the duovalve is ok, go to 7).
Now, hit the A/C button:
If the red light on the A/C button does not come one, you have a controller problem. Bring the car to Dallas, Texas and I can fix it.
If the red light comes on and the temperature of the air does not drop, but you hear the A/C clutch engage, you need someone good with auto A/C systems (and a lot of money).
If the red light comes on and the temperature of the air does not drop, and you dont hear the A/C clutch engage, you need someone good with auto A/C systems who also can troubleshoot to determine if it is a sensor that has died or if the controller recognizes a condition that the ECU is designed to refuse to run the A/C. This will cost as much or more than 7-2 and is very hard to get fixed because we live in a culture of deep ignorance of electronics. (Which is why I make six figures. )
I realize you came looking for an easier answer than the above, and if it is the duovalve the fix will likely be easy and kinda cheap. But you MUST determine if this is an A/C issue or if it is a problem with the heat coming on when you do not want it to. MOST of the time, the issue is the duovalve is opening when it should not. Very common and not hard to fix.
If this really is an A/C issue, well, A/C issues can be expensive and hard to get fixed. If the system lost charge because the pump died or the condenser sprung a leak, its pretty easy to replace the bad items and make things work again;EXPENSIVE but not all that hard. I STRONGLY suggest you determine what the actual issue is before you take the car anywhere. Duovalves are an easy DIY fix at home or at many small shops.
If you take the car to a CHyrsler dealer, (see my sigline, don't be a dumbass), it will never get fixed. If you can find an MB dealer or German Auto Car Shopt that will work on it, they will probably have it fixed in a day but it will be EXPENSIVE, even if all it is, is the duovalve.
Earlier this year I ran the test above a couple of times with mixed results (sometimes all good, sometimes not). I went ahead and did the repair on the duovalve and thought all was well. However, the problem (unpredictable occurrences of hot air blowing on the driver's side according to Cathy) has come back for quite a time. I just ran the above test again this AM and, of course, everything worked perfectly. My wife is the primary on this wonderful car (bought new in 2005) and she loves it, but we would truly like to have it working consistently well. I am getting a bit ancient now (closing on 80) and can't easily do the maintenance I have been able to do in years before (top hydraulics, top replacement, accelerator pedal, etc.). I will never take the Crossfire to the dealer, but we do have a reliable independent (somewhat pricey) repair shop nearby here in SW florida. There is no Mercedes dealer nearby. Any advice for how we might ensure the magnificent vehicle AC fixed once and for all would be most appreciated. Thanks in advance!
Earlier this year I ran the test above a couple of times with mixed results (sometimes all good, sometimes not). I went ahead and did the repair on the duovalve and thought all was well. However, the problem (unpredictable occurrences of hot air blowing on the driver's side according to Cathy) has come back for quite a time. I just ran the above test again this AM and, of course, everything worked perfectly. My wife is the primary on this wonderful car (bought new in 2005) and she loves it, but we would truly like to have it working consistently well. I am getting a bit ancient now (closing on 80) and can't easily do the maintenance I have been able to do in years before (top hydraulics, top replacement, accelerator pedal, etc.). I will never take the Crossfire to the dealer, but we do have a reliable independent (somewhat pricey) repair shop nearby here in SW florida. There is no Mercedes dealer nearby. Any advice for how we might ensure the magnificent vehicle AC fixed once and for all would be most appreciated. Thanks in advance!
If ONE side goes warm and the OTHER side stays cold, it is either the duovalve or the climate control module. (I do not think a failed temp sensor on the driver's side heater core/evaporator would cause this, let me think about that but again I don't see how, I keep going back to the climate module or duovalve.)
I will say, there are more and more complaints of failed climate control modules on our Facebook pages - our cars are aging and new failure modes are coming to our attention. I'd consider finding a climate control module from a "parts car" and giving that a try.
Attached below is PDF of how to remove/reinstall a climate control module.
For the heck of it, replace fuse #15 in the engine fuse box. That was part of the problem that I had when my car was blowing warm air. Fuse 15 provides power to the center pin of the duo valve.
My other problem was a potentiometer in the climate control unit. The fan speed would work sometimes but not others. Thanks to pizzaguy's advice I was able to find the problem. He also rebuilt my climate control unit.
I rebuilt my duo valve for the heck of it. All is working great now.
Thank you to both of you for the quick replies. I will have a look at the #15 fuse. As to finding a replacement for the Climate Control Module (partno 05099162AA), I'm guessing that will take a while with no guarantee of success any time soon, but I'll have a go. A happy wife is a happy life and she is really attached to this Crossfire :-) Edit: I have done some research and found a few offers for the Control Unit on EBay plus one from a Patterson Auto Wrecking (Pattersonaw.com/parts/CHRYSLER/CROSSFIRE/24H0702/2005/TEMP_CONTROL/1369931/) which was the lowest listed price at $100. The Ebay ones are significantly more expensive. I also reviewed the Crossfire Service Manual and see I would need a special Radio Removal tool 9241 (or 3291?) which seem to be available online but the pictures do not match the illustration in the Service Manual. Wondering if that (the special tool) would be a problem and what you guys might think about the various control module offerings.
Thank you to both of you for the quick replies. I will have a look at the #15 fuse. As to finding a replacement for the Climate Control Module (partno 05099162AA), I'm guessing that will take a while with no guarantee of success any time soon, but I'll have a go. A happy wife is a happy life and she is really attached to this Crossfire :-) Edit: I have done some research and found a few offers for the Control Unit on EBay plus one from a Patterson Auto Wrecking (Pattersonaw.com/parts/CHRYSLER/CROSSFIRE/24H0702/2005/TEMP_CONTROL/1369931/) which was the lowest listed price at $100. The Ebay ones are significantly more expensive. I also reviewed the Crossfire Service Manual and see I would need a special Radio Removal tool 9241 (or 3291?) which seem to be available online but the pictures do not match the illustration in the Service Manual. Wondering if that (the special tool) would be a problem and what you guys might think about the various control module offerings.
Hi, you don't have to buy a new one. You can remove the one you have and have it repaired by @pizzaguy. If you ask him nicely .
It's not hard to do. Here are links to my posts with detailed pics on how to remove and reinstall the climate control unit:
When the A/C in my Coupe started blowing hot air out the Driver-Side but cold air out the Passenger-Side, I performed the attached temporary flush to see if the Duo Valve was simply clogged up with residue from the Coolant. Turns out that fixed the hot air flowing out the Driver-Side and the system continues to perform to this day (been close to 2 years since I did the flush). With a try!
Hi, you don't have to buy a new one. You can remove the one you have and have it repaired by @pizzaguy. If you ask him nicely .
It's not hard to do. Here are links to my posts with detailed pics on how to remove and reinstall the climate control unit:
Re: AC suddenly blows hot air, any suggestions?
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