dRockSL55

Having an issue with my SL55.
The A/C condenser had to be replaced, the A/C compressor was not engaging due to low refrigerant from an a/c condenser leak. This caused the AC off lamp to come and stay on. Pressing the AC off button would cause the lamp to flash then go solid once again.
The condenser has been replaced, and the Refridgerant replaced.
SDS/STAR was required to override and turn on compressor to fill.

The system is now fully charged, A/C works beautifully and ice cold using manual compressor override through star. However the system will not operate normally / engage the compressor without star. The AC off lamp remains and will flash when pressed. There are NO FAULT CODES for the AAC through star/SDS which has me perplexed.
Any help or insight? Thanks!

Plutoe

It's a pain in the *** however I would disconnect DAS Xentry then I would disconnect the battery wait 5 minutes then reconnect every thing---wada you get!!

dRockSL55

I think I found my solution;
Models 203, 209, 220 (up to August 2002 production) and 230 (up to August 2003 production)

1. Using STAR Diagnosis, enter the following menus: [Control Units > Air Conditioning > AAC control unit > Actual Values > A/C Control].

2. Observe the value for sensor (B12) Refrigerant Pressure Sensor.

3. Ensure the value for B12 is within specification.

4. Using STAR Diagnosis, enter the following menus: [Control Units > Body > EIS > Control Unit Adaptations > Read Coding and Change if Necessary > Climate Control >Refrigerant Level Check].

5. Set the coding for Refrigerant Level Check “INACTIVE.”

6. Select F3 and transfer coding to the control unit.

7. Remove STAR Diagnosis and verify that the A/C Off light is not illuminated by default and will turn on/off after pressing of the A/C Off switch.

dRockSL55

^^That didn't work. The EIS coding did stick, but same AC off lamp / no compressor engagement behavior

I'm going to give the batt disconnect trick a try, thanks for the suggestion Plutoe

dRockSL55

No dice :/ any other suggestions? Checked EIS coding once again and refrig level check is inactive, still no AAC faults. Really Frustrating me now!

mbwolf

I just found this post from Quadcammer:
"Run climate control diagnostics to check for codes. If there are no codes, run through the different parameters and check for any that don't make sense.

The 210 forum, sticky section at benzworld.org has good info on how to access this info. I know how to get to parameters (both temps at 72, hold rest button, then use temp buttons to scroll through), but I can't for the life of me remember how to get to the codes."

Maybe this helps to see what input is missing

Wolf

mbwolf

Any update on your issue?

kustom2k1

Most ac issues are misdiagnosed and its the temp sensor in the dash.

NiceMerc

Hmm... I wonder if I'm dealing with a similar problem...

Starting from cold with the roof up, heating/cooling on auto and temps set at 72 degrees, everything warms up nicely.

Ten minutes later on the freeway it starts to get cold inside and I have to turn the temp up.

Ten minutes later it's even colder and I turn it up again.

An hour into the drive I'm turning the dial up to 80 degrees and backing off a little to get any heat into the cabin at all.

I've tried turning off the AC, adjusting the vents, switching to manual but nothing helps, I get lots of cold air and have to dial the temp way up to keep warm.

Any ideas?

Thanks
Gary

dRockSL55

I've been working crazy hours the past few weeks so haven't messed around with it. I will update next time I work on it, but im still not sure where to go from here as I couldn't get the trouble code through star


Also thank you for your post of the AC self diagnostic, unfortunately on the r230 there is no AAC display so no code readout

dRockSL55

This would cause the AC compressor to be disabled (with AC off lamp stuck on) ?

When monitoring the actual values from AAC system sensors through star everything seemed in check

kustom2k1

Drock... I had the same exact issue you describe in your initial post. Replaced the compressor and dryer (1k spent). Turned out to be the temp sensor in the dash. Its going on 3 years now without an issue.

dRockSL55

Thanks for the info. You don't happen to have a part number for the sensor you replaced, do you?
Did your AC OFF light (and compressor engagement) reset on its own?

jsarg419

Having the same issue. AC OFF light on press it and it blinks on/off 3 times then stays lit. gauges in a/c system show 100 psi both sides with car running. Ambient 80F. So no compressor activity and good (enough) charge. Temp sensor make sense. If reading too cold compressor would not need to compress until temp raised so it would keep it off. Part is $20 on ebay. will give it a try at this price.

dRockSL55

Let us know how it works out and the part number please!

I still haven't fixed this problem, have had too much going on and my evaporator started leaking on top of that which I still need to take care of (ugh) before moving forward

jsarg419

Sill waiting on part.

kustom2k1

Im pretty sure this is it, double check though with Mercedes parts department.
https://www.ecstuning.com/b-acm-part...208300772~acm/

WUBEKUMI

HI dROCK, WANT TO ASK IF YOUR PROBLEM WAS RECTIFIED.
AM HAVING SIMILAR ISSUE WITH AN SL500.
THANK YOU