HELP!!! A/C Compressor - PeachParts Mercedes-Benz Forum

RichardLSU · #1 08-07-2008, 03:53 PM

Ok, my original A/C unit was replaced by the PO with the newer R134a system to update the car and make it cheaper to charge. I have a leak, somewhere, so there is no pressure building in the system to turn the A/C compressor on. But when you bypass it there is still no power. Is there a switch or a relay that takes care of that? If I could get an electrical diagram for an 85' W126 300SD that would be great too. Shot in the dark I know but I thought I'd put it out there.

I've done some research and there seems to be alot of people with similar problems (no power to the compressor) but I never was able to find a definite solution. WHAT IS GOING ON HERE???

Thanks everyone, without you all I'd be on the side of the road.

Jetmugg · #2 08-07-2008, 03:56 PM

Are you saying that if you jumper the leads to the A/C compressor clutch, that the clutch will not engage?

SteveM

rrgrassi · #3 08-07-2008, 04:02 PM

85 also introduced the Klima relay.

Have you checked the fuses also?

RichardLSU · #4 08-07-2008, 04:03 PM

No I didn't bother to check the compressor itself, rather, there is an accumulator/dryer in the left fender that (usually) houses the switch to engage power once there is pressure in the lines. There was no power going to it. Usually one of the wires to it would be hot, but there was none to be found. Which suggests there is something bugging up my electrical system.

The tach works fine, sunroof works fine, heater works fine, absolutely everything in that car works fine except the A/C so I figure its not anywhere in the harness. I'm just stumped.

RichardLSU · #5 08-07-2008, 04:04 PM

Yes, fuses are good. And relays are fine to the best of my knowledge.

Kilma Relay? Please elaborate.

RichardLSU · #6 08-08-2008, 03:47 PM

Anybody else have any ideas? I'm driving back down to Louisiana for school in a few weeks and I would really like to have this sorted out by then. Thank you!

StevenHamilton9 · #7 08-08-2008, 04:40 PM

I have a similar situation in my 82 300D. However, I'll be driving from Chicago to Miami...Again. probably still with no AC

RichardLSU · #8 08-08-2008, 04:52 PM

Yeah, apparently this is a common problem. I'm wondering if I should just start replacing relays and switches and see if it fixes it. I hate to do that though considering the relay is $350.

rrgrassi · #9 08-08-2008, 05:15 PM

Someone with an '85 should chime in. I did see where someone used an "ice cube" relay in place of a klima on an '85. My car is an '82, so not klima. IIRC the '85 uses the klima in conjunction with the EGR computer and tach. No tach signal usually means no A/C compressor engagement.

StevenHamilton9 · #10 08-08-2008, 05:30 PM

I don't want to hijack the thread but if anyone has advice on the '82 because I'm not receiving power to compressor.

RichardLSU · #11 08-08-2008, 06:38 PM

Its probably the same system. I know alot of w123 parts are interchangeable with a w126.

RichardLSU · #12 08-09-2008, 09:39 AM

Quote:

Originally Posted by rrgrassi

Someone with an '85 should chime in. I did see where someone used an "ice cube" relay in place of a klima on an '85. My car is an '82, so not klima. IIRC the '85 uses the klima in conjunction with the EGR computer and tach. No tach signal usually means no A/C compressor engagement.

I guess the Kilma is the A/C relay then.

When I bought the car the tach wasn't working, but after driving it a few thousand miles it started working again, so I figured my A/C would too. It doesn't though, but the tach is still working.