Brian

I got no response on my meter. With Klima installed, started car, middle button, max cool setting, blower operating. Clutch engaged and and after about 3 minutes, I could feel hot and cold lines. 2 more minutes and I took it for a short drive (1/4 mile) and returned. Clutch was not engaged, I shut it down, removed Klima and took the ohm reading, nothing. I was readind from the neg battery post to socket #10. I checked the meter back to ground and got the inf buzzer and reading.

Reinstalled the Klima, and repeated everything except the drive. The clutch only stayed engaged about one minute. Removed the Klima and took the reading and got the same result.

Where now sir?

Thanks.
Harry

Yep, I had the exact same issue and symptoms.

Change the CCU.

Thanks Brian, I think I'll do a resolder job and see if that will fix it, (sigh). I did that on my other SDL (1100 solder joints as I recall) about three years ago and it fixed the problem, my compressor bombed on it about 9 months later. I plan to take it all the way back to R12 one of these days but I've got to get a little smarter and a few more tools.

Thanks for all you do for all us rookies.

Harry

If you're successful...........I got two more of them sitting here with your name on them...........

Brian

Jim Cathey has just hung out his shingle for this type work and is very reasonable. Check out his notice:

http://cathey.dogear.com/mamerepairs.html

He is one of my favorite listers on the OkieBenz Diesel List.

On 7-17-06 I sent him a cruise amplifier to repair ($40) and he mailed it back two days later. He has rigged a bench test and mine failed coming in and passed after a resolder. I should get it back tomorrow and I'll try it in the 81 240D. Knowing him from the list, I'll bet it works.

Again, thanks

Harry

Thanks for the link. I might just take a shot with the pile of CCU's that I have sitting here. Chasing old units on e-bay is getting tiresome.

i just came back from the junkyard with 2 ccu units, i replaced them and my ac didnt work i head the noize of a little air comming.. but still it was on high and the air was not comming out sufficiently. what should i do now? should i change the blower or any other suggestions??..

could it also be the blower motor regulator?

That's the next culprit. If the CCU is good, and the blower won't operate, it's the controller or the resistors.

any idea which resistor it should be?

If it's the resistors, you typically replace the entire group.......but they rarely go bad.

i have a feeling that its going to be the controller... how can i check that? and the resistors are they the little pin things that come into the ccu? or it is something different?

Don't know if there are any tests for the controller.

The resistors are part of a "resistor bank" which is a steel framed box about 3" x 3" x 3" with holes punched in the case. It normally lives down beneath the brake booster on the W126. You really need to look carefully to see it........and.......I'd imagine that it's a real PITA to remove. However, the way it's designed is such that any one resistor failure would cause only one blower speed to fail........in every situation but one. So, the controller is probably the more likely culprit.

so this morning i was determined to go opoen and check out that blower motor. But before that i decided to check the fuses. There was a fuse thingi by the brake booster, i opened it and vualla i saw that that strip fuse was cracked! so could that be the thing that is causing my a/c problem?!?!?!?! =]??

Good grief, yes. That's the updated fuse for the blower motor. 30 amps, I believe. Check that, though.

__________________
The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)