davisleaphart

All,

I have always used this forum and enjoy your help. Today, I started up, and something was off (was an initial weak crank), but then everything was fine. All of a sudden, I realize that the A/C is blowing hot. Then an error message popped up on the multi-function display, that was the picture of a thermometer. There was no other message like Low Coolant that is normally accompanied by the same graphic. At the same time, the temperature gauge went from 85C, to right at 80C, and just stayed there. At times it would roll up and down around the 75-85C mark.

This is what I do know so far:

Coolant level is fine
The radiator fan is not coming on
The top radiator hose has little to no pressure when its hot
The A/C blows hot
I have the Thermometer graphic and stuckish gauge
The gauge works until 85C where the error message pops up
No diagnostics codes from the OBDII


Any ideas on the cause of the problem? Also, do you think it is safe to drive, or do you think it is ACTUALLY overheating?

Russell Ormerod

do a short test with star and send results

davisleaphart

I don't have STAR. I've contacted a guy in Houston who has it and am seeing if I can meet up with him. As I get more info I will continue to update.

I do know that this morning, I turned the key to position two and the fan came on. So I don't think the fan is seized up. What components are linked to both the A/C and temperature gauge?

VVF

Where are you located? I have star.

davisleaphart

I am in Houston near Pasadena down 45.

I'm meeting a guy tomorrow with Star. I'll post the results and any discussion we have.

Earliest MB Clearlake can get me in is an entire week. Seems kind of ridiculous.

I'm holding the appointment until I run star. If it's an easy fix I'll do it myself, but if not......$$$

davisleaphart

So,

I worked with JN today in Houston (really smart and helpful), who has STAR. The diagnostic code that was pulled was M4/7. I don't remember the exact verbage, but at the end, it said OUTPUT.

I think that my A/C not working may be because the car won't allow the compressor to run without the fan working. Or, it could be an independent issue as.

Anyway, I went home, I have removed the fan (kind of a pain, but not too bad). I am going to order another one and hope that fixes everything, part # 2035001693. However, before I do, do you think there is anything else I should check? I have looked at the fuse, and it is good. The relay is supposedly built into the fan. I don't know if there is any easy way to troubleshoot it?

cvx

STAR has very clear diagnostics when it comes to the AC, see picture I am attaching. It should be 100% clear whether the fan is running and what the output compressor is giving. I am afraid you are changing parts in vain and throwing money at it. Did you see the following picture and what were the readings?

Are you sure it was M4/7? M4/3 would be the fan

(Sorry for the translations, it was in Finnish originally when I scanned my own car)



Another one

Russell Ormerod

the fan itself will not cause the temp gauge to fluctuation! you should of actuated the Fan with star. I have had ECUS fail on the PWM output to the fan. I would first investigate why the temp gauge is not stable.

davisleaphart

I did try to actuate the fan. It didn't respond.

The temperature gauge moves to 80C when the multifunction display shows the temperature gauge icon. This stays present for a second, then the display disappears and the gauge moves up to where it should be. I believe the temperature gauge moving is just an alert that coincides with the fan not running?

Either way, I have a fan coming overnight and will see if that fixes anything and will update once it is in.

STAR didn't have any error codes other than M4/7.

Russell Ormerod

OK. you right coolant warning symbol does indicate a Fan issue. sometimes water gets into fan module. if the fan does not fix the issue. you need to scope test the pwm signal to it

davisleaphart

Alright, so for those of you who care, and to help anybody else who has run into this issue, replacing the cooling fan in the front of the car was the fix for all the problems. It probably took two hours. You just removed the front support beam/guard thing with the four bolts and a that are seen and the two that run down into the front of the car supporting the horn. You may want to disconnect the horn and you will have to remove the wire that triggers the hood release, it literally just unclips. After that, the fan is held on by just plastic clips on the side, with the plug being at the bottom. The hardest part was just getting it to fit out, and getting the new one back in. But you can do it without removing any coolant hoses.

If you have questions feel free to PM me or post here.

SincityW203

Before you replace the fan clean the connection on the power plug on the bottom of the fan housing, fixed mine right up.

zzdragonz