Hi guys,

I'm debugging the A/C on my 300GD W-Wagen.

http://www.peachparts.com/shopforum/3130851-post13.html

SOMEONE has been hacking the wiring for the A/C (and associated external cooling fan, etc.)

Note that the engine bay of the 300GD is virtually identical to the 300D (i.e. it has a OM617 with all the normal W123 bits... only a few things, like the air cleaner, are different)

Being familiar with my 240D, I realize that normally:

1) the A/C compressor clutch is connected to a low-pressure safety switch on the dryer/receiver.

2) the external auxiliary fan is controlled by a temperature switch on the dryer/receiver.

However, someone has been tampering with the wiring, and it's all screwed up. For example, the dryer/receiver installed has only ONE switch (I assume its a pressure switch, since that's more 'normal' with A/C systems), and they've really connected everything in a really convoluted way.

Anyway, the question is - should I pick up a new pressure and temp switch from the dealer, from NAPA, or from the junkyard? Recommendations?

Thanks,

Packman

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83 240D - 4 speed manual - Manilla Beige
189K miles, Tachometer mod, cool wooden shift knob from PeachParts, CocoMats, Original factory paint, manual windows, manual sunroof. Starting to add AudioWrap to this car too!

It's possible that the GD has a different method of measuring temperature for the aux fan.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Fooey!

The 300GD service manuals are useless for this repair! The photos look nothing like what I have on my rig.

Therefore, I think that the AC is an aftermarket unit.

I believe the switch is a combination pressure/temp switch (or at least the the previous mechanic wired everything together on the same sensor/switch, and didn't label anything.

Since I need to replace the dryer/receiver anyway, I am planning to pick up pressure and temp sensors and convert it to a normal W123 setup.

Sincerely,

Packman

__________________
83 240D - 4 speed manual - Manilla Beige
189K miles, Tachometer mod, cool wooden shift knob from PeachParts, CocoMats, Original factory paint, manual windows, manual sunroof. Starting to add AudioWrap to this car too!