1986 1987 300D 300TD A/C Heat CCU Rebuilt from Programa - PeachParts Mercedes-Benz Forum

David Hendy · #1 07-20-2010, 09:55 AM

I have a CCU pushbutton unit for a 1986 1987 300D sedan or 300TD wagon

MB part number 1248301885

Was rebuilt by Programa in 2003, still has the seal intact.

These are the correct units for the 86 & 87 603 diesel 124s, not the 1248303385 from the later cars

$100 + shipping

Tpawlik · #2 07-27-2010, 09:06 AM

I realize you are selling a part and not repairing/diagnosing A/C systems, but I just bought an 87 300D. The PO hot wired the compressor. I have read others have done the same. Without the hotwire would the compressor not run at all?
My A/C works with fresh air button, the regular A/C button and the max A/C button. The thermostat wheel works as does the Auto fan button. It takes about fifteen minutes to start compressor/cooling. Do people hotwire the compressors to avoid buying a new CCU? If a new CCU would make my A/C work properly even though the compressor is hot wired I would buy one.
Thanks.

David Hendy · #3 07-27-2010, 10:06 AM

What does "hot wired" when used in conjunction with teh a/c compressor mean? I would think it means a toggle switch on the dash that you press & on comes the a/c.

But that doesn't sound like your situation.

But getting back to basics...

You have good freon pressure? Checked the klima relay?

Why was it "hot wired" in the first place?

Tpawlik · #4 08-02-2010, 12:01 PM

Thanks for the reply. I will have to photograph the wiring. The PO tapped into a wire on the drivers side of the engine and ran it to relay they added. One of the wires coming off the relay is connected to an empty fuse holder in the fuse box. What I call hot wired.
The relay they installed can be had for $5, but would it take the place of the "Klima" relay?
Unfortunately, I am not at all familiar with A/C systems let alone MB systems.
I have a shop manual coming. Hopefully, between that and some help from you and the forum I can figure out was has been done and restore the wiring to it's original state and ultimately get the climate control working properly.
When the compressor finally starts, the AC is cold/normal. When the heat is on it is also hot/normal. But they both work with the Economy, A/C or Max A/C button.
Thanks again.

punkinfair · #5 08-02-2010, 02:16 PM

sounds exactly like a car i looked at for sale a few years ago. the issue was the temperature or pressure switch on the receiver/dryer goes bad and the only correct repair involves a purge, replace the switch and refill. so this person hotwired a relay for the auxiliary fan so it was running as soon as the compressor was running, in other words always. try removing the relay and see if the auxillary fan still works.

digression - they actually drilled a hole in the side of the fuse panel, soldered onto one of the fuse terminals and ran the relay dangling off some wires near the power steering pump. i discovered this after agreeing to buy the car, and the work had been done after we made the deal - he said he needed to 'replace a relay to make the fan work'. we backed out of the deal for the car.