I have removed all parts of the AC in motor bay and the evaporator
and I have tested continuity for the compressor clutch (problem is that Ground to compressor is not connected to Battery minus/body).

I have re manufactured the Aeroquip hoses with original fittings, I have flushed the condenser and evaporator, replaced the expansion valve at evaporator (evaporator is assembled and back under the dash- what a drag to R&R the evaporator) and I have a new compressor, new drier with temp switch and new cone seal rings for SAE flare connections on the shelf.

Remember I am doing this job in Oman and have not much equipment.

I have on the shelf also couple cans of R12 and I have the correct oil for R12.

Now the question is how to start the assembly: Most difficult part (after the evaporator) might be the compressor.
Questions:
How do I charge the compressor with the 300ccm of compressor oil? Where do I put the oil? Suction port?
Is there the problem that I might loose some oil during installation of the compressor by moving the compressor around under the car?

Is it wise to install the 2 hoses at the compressor before installation or after?

I installed the AC fan on the passenger side (the AC fan is plugged in already and it works) and found that there was one plug left over. I couldn't find the female for the male plug. I'll attach the picture.
I even removed the glove box in order to find the socket. But I couldn't find it. But I saw that the cable comes with the cable tree where one branch is plugged into the evaporator (a 4 prong plug).
Can someone tell me what this open plug is about?

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You're fixing the a/c now that you're back from Oman and it's almost December in Boston?

Pour oil into the compressor through the suction fitting hole while it's off the car before you mount it. Then turn the compressor so that you move the oil around.

__________________
With best regards

Al

I am still in Oman...no in Boston I couldn't get the idea to fix the AC.
Thanks...so I'll charge through the suction side..The bigger hole I guess.
Best, Martin

I am still questioning how to connect the AC fan properly.

Right now I have plugged in the AC fan through the socket coming from the evaporator box. Fan works this way.

So this cable from the evaporator box is connected to a weird switch or fuse inside the evap...whatever this thing behind the 4 prong connector in the picture is.
Inside the evap it has 2 springs and points.

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Is there a chance that this plug might be unused? ...meaning that there is no female part to it. This means that the cable with the male pins are just hanging around and unused?

Okay, no answer for that one. Anyhow I have the evaporator back in, the ac fan works and I am ready to charge the compressor as it is sitting on the shelf.
Next step is charging the compressor, then installing the Rotalock assembly with the 2 hose connections compressor to Rotalock. I'll take pictures this time.

Martin

I'm futzing with my (108 280SE) A/C now that winter is in full force here and I have some time before summer.

In taking a look under the dash, I noticed that on my car there is a two-prong plug almost directly below the round vent, up against the back of the lower dash curved piece. No idea what mine is for, but it looks to be in the same area as yours in case you are wondering where it may plug in to. The wires on mine are jacketed, but on one I see it is thick (12ga?) and black with green (listed as sw/gn on the wiring diagrams).

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Looking for Early 108 windshield surround wood in decent-to-good condition.

Hi Paolo

My 'open' cable is also jacketed and it comes from the same cable strand that also goes into the weird switch inside the evaporator.
I don't have the elctr. diagrams unfortunately. Would be easier.

Anyhow it seems that all electrical AC components are working.
I am happy that the signal to the new compressor also works well.

I installed the new compressor today and also installed the remanufactured aeroquip hoses.

Now I am about to install the rest of the hoses...maybe today.
Best, Martin

update: I have the engine bay installed...
compressor, Rotalock assembly, re-manufactured hoses (aeroquip) and condenser/drier.
I put 150ccm oil into the compressor and 150 into the new drier.
compressor started! I torqued all hose connection. I drew a vacuum for 30 minutes and system held vacuum well. Then I put around 1000g R12 in (3 cans)
pressures seem to be normal. it was around 85F ambient and high pressure went to 200psi.
System seems to function well. Temperatures at vent around 8 - 10 degrees C.

Only thing is the aux fan is not kicking in even with cooling temps at 100C.
Anyone who can help me tackle this problem with the aux fan. aux fan is running if I put ground on the temperature switch at the fat cooling hose.

Martin

Good Work Martin, I have seen the second two temp switches not the first picture. they can be tested with an ohm meter and boiling water. can you please provide the hose specs as I need to do the same job on a few cars. The 6.3 runs now just needs interior put back in, 4.5 motor needs assembly. BrianO.

The 100C (or 97Celsius) switch I have installed looks different than the one that MB carries for the 3.5. The MB switch has a pin with a plug. I wonder if there isn't a switch that does 90 C? Do I need to drain the coolant for changing the switch?

For the hose renovation: do a search for my name. I posted the reman process of the aeroquip hoses.. I use not the original ones (braided) but used a cheaper black rubber hose...with old fitting all work fine...you need the cone copper seals. evaporator is a drag.. also getting the compressor in and out. But the rest is just work.

Your a/c system will have pressure switches (high and low) that will trigger the fan when the a/c is running if the pressure gets too high. This is not related to engine temp.

Your 212 switch will trigger it if the engine gets hot regardless of whether the a/c is on.

If your fan is engaging when you ground the wire, you could either have a faulty switch or air in the system. As mentioned, the switch relies on hit water so if there is air where water should be, then it may result in the switch not functioning properly.

__________________
With best regards

Al

I have just one temerpature switch at the drier. It triggers the aux fan when temps there exceed 62 C.
The 100C switch is dead I believe. The upper connector is loose somehow in the switch. At least my assumption.
I'll find out.

Also check if there's an air pocket. I had that happen on my 6.9 and while the switch itself was not faulty, it acted that way because there was no water getting to it.

__________________
With best regards

Al