Intermittent A/C (not working) and Auxiliary Fans

[zadefaraj]

Hi,

I've searched to find a solution for the newest problem troubling my 95 c280, but haven't made much progress. Currently, my 202 has a bypass switch installed on the two auxiliary fans in front of the radiator (identical to the one mentioned by jnenad) that completely bypass any connected relay. I bypassed them because I noticed my car was overheating in the Texas summers and that the auxiliary fans would turn on and off at will. From my understanding, these only come on under certain specific conditions. I never quite found a solution to the problem, thats why I bypassed the system.

This worked for quite some time, keeping my engine cooler but now, a year later, I came to turn my A/C on and the cold air would only last a few seconds. It appears as though the compressor now turns and off intermittently., along with the cold air.

I have checked that there is enough freon in the system, and I believe the clutch does engage properly. I have read that the A/C system is somehow interconnected to this fan relay, but I'm not sure if it could cause this problem somehow so much further down the road. I've also read that low radiator fluid could also cause A/C woes.

I don't physically have the vehicle with me at the moment as my mechanic is searching frantically for a solution, but I don't think he'll figure this one out. Also, he did say the car threw out a number of codes when tested.

If anyone has had this similar intermittent A/C or fan problem or could help me out in any way, i would be forever grateful because the texas sun is not as forgiving.

Zade

[zadefaraj]

Okay, well I got the car back today and the mechanic said that the A/C actually only turns on once and will blow cold air for about 2-3 minutes before it turns off. It will only blow cold again once the car has been restarted. He also said that they refilled the system with freon, applied vacuum, tested the compressor several times and even checked the speed sensor. The compressor works fine, and he was under the impression it was an electrical problem.

I do recall in the vehicle's record book that the engine wiring harness has been replaced previously, and I'm thinking there may be a short somewhere. My mechanic also told me that the engine threw just about every code possible. I would like to check the codes myself, so i'll go ahead and search the forum on how to do this and post the results shortly.

<followup>
I tried to get the codes several times just to make sure I got them all and this is the list I compiled..

25
59
END

26*
28*
60*
78*
80*
82*
86*
90*
94*
98*
102*
106*
END


:(

[xvvvz]

It sounds like you have the digital readout that can be used to diagnose things. Did you follow the directions on this page and then go to the page where you input your codes so it would then give you a diagnostic translation?

http://www.eclassbenz.com/node/27

[zadefaraj]

I have the older climate control unit not pictured in the link you sent, instead I used this method to obtain the previous codes.

http://www.club202.com/forums/showthread.php?s=&threadid=7642&highlight=icing

I have a feeling its one of those sensors because in the beginning of that thread, nokia8860 accurately describes the problem. Also, do you know what the meaning of those codes are?

[xvvvz]

>>Also, do you know what the meaning of those codes are?<<

They are listed in a table in that thread you cited.

I would clear all the codes you have stored and then drive it a bit to see what comes back again fairly quickly.

[zadefaraj]

For anyone interested, I replaced the engine coolant temperature sensor (http://img.eautopartscatalog.com/live/R107526553BEH.JPG) for $30 and that did it. It was error code 25 on my 95 c280's climate control LCD. After replacing the part and deleting the code, it was back to normal.

Btw.. the engine coolant temperature sensor is located next to the thermostat and another sensor.

Thanks for the help xvvvz!