Fixin' the A/C on 300GD G-Wagen. Should I cob parts from a W123?
 

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

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

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