A.C. Problem.. - PeachParts Mercedes-Benz Forum

McDiesel · #1 08-21-2004, 12:50 PM

why me! the thing that bothers me is now the tach is not working either...

will report back later after car cools off to re-check .. now i cant even look at the tacj to see the slight drop in rpm when compresser is engaged!

you can times that icon by a ga-zillion im so mad! :>

on another note I just purchased a 1977 jaguar xj6c coupe..

at least now i can drop off PROBLEM

car and still have wheels

to get around

#2 08-21-2004, 04:08 PM

Check the condition and tension of your serpentine belt. If it slips, there is a sensor on the compressor that kicks out the compressor. Turning off the ignition and restarting the engine resets it.

The next thing after that to check is to see that the temp sensor sample blower motor is running.

Good luck,

McDiesel · #3 08-21-2004, 04:48 PM

Just replaced belt shock tensioner, and pulley, new belt, and thermo viscus clutch, plus altenator less than 3 months ago..
Already had to replace the voltage regulator < less than 3 weeks after rebuilt one> No warranty on electical parts, hehe

But Im still Baffled on the Tachometer stopping at the same time..

I was reading the testing procedures on it.. just not in the mood to go under car today.. ... and not enough strenth to pull cluster out in this 95* heat and 100% humidity in Jersey...

larry how do I check that sample blower temp sensor motor.. < and where is it ? > im not as smart as look

your not talking about the sensor on the roof near the interior lights are you?

BTW I just replaced the blower motor less than 3 months ago due to the old one was shot...

my temp gage is reading its normal 80-90*C

McDiesel · #4 08-21-2004, 04:59 PM

the blower motor works fine.// low, high, and auto all turn the blower on and it is functioining properly

Thanks,,,,

BrierS · #5 08-21-2004, 05:42 PM

The "sample blower motor" attached on the right side just inside of where the glove box is. If yours is in the same place, you remove the glove box and should see (with a light) a hose similar to a garden hose attached to the sample blower motor. Following LB's advice I followed the hose, pulled the motor from its mount, removed the hose and was able to observe it working. The hose runs up to the sensor near the ceiling light you mentioned. Still following the advise, I inserted a hose within the one removed from the sample blower motor and blew on it to see if air flowed to the sensor. It did. I put a piece of tissue where the hose connects to the blower and it barely held the tissue in place (should hold it as it should up at the sensor).

If you have the KLIMA behind the battery SB mentioned searching for the Ice Cube relay bypass. I never had to go that far (yet) since switching the ICE Cube relays (under the cover behind the fuse cover) around and cleaning the KLIMA contacts and putting dielectric compound on them did the trick getting my compressor to run again. Wish I knew which of the many little things I did helped but I don't. I'll certainly follow your post.

Might I suggest that you get your hands on the Mercedes Service Manual Automatic Climate Control. I just received mine and have started preparing to go through their procedures. Between it and the posts here on the forum, I am going to be replacing all of the pods behind the dash. Lots of good posts on that.

Use the search and you should find four posts on here that have substantial details on these ticklish systems.

stevebfl · #6 08-21-2004, 06:14 PM

If you have no tach then you probably have no engine speed signal. If you have no engine speed signal to compare to the compressor speed, Klima shuts off the compressor.

The engine speed signal is made by the EGR transducer. The EGR transducer is powered by the OVP relay if I recall.

psfred · #7 08-21-2004, 09:58 PM

I second steve -- get a new OVP relay and install it. Should cure the rough idle, too.

Peter