'82 300td AC question Help - Page 2 - PeachParts Mercedes-Benz Forum

leathermang · #16 07-11-2010, 08:21 PM

Always wear goggles when working on AC.

zeke · #17 07-11-2010, 10:27 PM

Quote:

Originally Posted by leathermang

Always wear goggles when working on AC.

VERY good advice!

Treeman · #18 07-11-2010, 11:46 PM

Well thanks for the help everyone of you. I am hot and tired, I am putting it down for the evening and will drive my truck on Monday. I will start working on this again Monday evening, man where did the weekend go?

Treeman · #19 07-13-2010, 10:06 PM

Ok, here is what I found and what I did. Compressor was not engaging rewired connection and compressor comes on NOW. HS fan working now. Monovalve inspection, rubber was fine no holes in the rubber. Bypassed connection between mono valve and dasc control and wired mono valve direct to fuse box and now have cold air. Problem lies somewhere between monovalve and AC unit in dash. I believe the problem is in the thumb control. I'll go at it again this weekend.Thanks for the help everyone!

leathermang · #20 07-13-2010, 11:38 PM

By ' thumb control' do you mean that vertical wheel ?

Treeman · #21 07-14-2010, 08:02 PM

Yes the wheel. I see there is a rebuild DIY but I'm skeered to dig into that one. Melting solder points is kinda intimidating to me.

leathermang · #22 07-14-2010, 08:56 PM

Your TD has a type 2 or 3 AC ( my 240 a type 1 ) .. the diagnostic part of the manual for just that dash unit with the buttons is 80 pages long... I do not blame you for not tackling it..
I pretty much sold my 81 TD due to fear of addressing it... it took my punching the buttons only as mere suggestions to be ignored or acted on much later... a mind of its own.
As to serious soldering.... I do not try that myself either... see if your local computer repair shop has someone who can do motherboard soldering... and ask them what they would charge... I had that need on a Honda transmission computer motherboard lately and my local guy charged me $20... well worth it to me.... it is easy to delaminate things which should stay intact if you do not have the correct tools and experience..

Treeman · #23 07-14-2010, 09:12 PM

The German mechanic I use in Tyler, Tx. told me the unit I have is the hardest and most expensive to work on. My reply was "You want to buy a car"
Good advice, I will talk to my local computer guy and see if he wants to give it a try.

funola · #24 07-14-2010, 09:39 PM

The temp adj wheel can be removed and cleaned with brake clean, a pencil eraser and reassembled. That may be all you need to do.

Treeman · #25 07-14-2010, 11:11 PM

Quote:

Originally Posted by funola

The temp adj wheel can be removed and cleaned with brake clean, a pencil eraser and reassembled. That may be all you need to do.

I will give it a try as long as I dont need to plug in the soldering iron.

showme · #26 07-15-2010, 02:02 PM

I'm finally getting ready to take on my wife's AC. This post has been a big help with a lot of the questions I had. I had a buddy vacuum and recharge the system-no help. I've got a new control head for the auto control heat\AC that I'm going to put in. I've checked the monovalve visually, but not electrically, and it looks ok. But this simplified doing a volt check. And the explanation of the "foam hose" I've heard so much about helps, too. The control to the compressor I knew nothing about. I've also bought a vacuum check valve that's supposed to go behind the dash somewhere. Figured I'd find it when I open everything up and replace it no matter what. Thanks for the question and thanks for the answers. You've given me confidence to do this. Now, if I could just find a cool place to work on it. It's 98* here in southeast Missouri, and I don't even want to think about the heat index. Procrastination is a form of self torture, I'm beginning to see.