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  #1  
Old 06-28-2007, 06:22 PM
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Reviving a W124 AC system. Where do I start?

I have a W124 I've been reviving from storage (PO let it sit for 3-4 years). I've got it running very well. But now I'm moving to the Climate Control system. That's not working well at all. Anyways, on the AC where do I start? Here's my analysis:

1. Pulled Klima relay and tested for ground on pin #10. There was no ground. I pulled the CCU and found a bad transistor. I changed it and I think it may be fixed. Haven't plugged it back into the car yet. But question number one:

If the freon level is very low (It is, I pressed the valve and very little pressure), will the #10 Klima pin still show a ground with the AC button pressed?


2. What do I need to do to not kill the compressor after I get it to come on for the first time? I'm assuming it may be unlubed after a long period of not turning.

Thanks!
Nick

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  #2  
Old 06-28-2007, 06:47 PM
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Don't run it 'till it's charged, you will want to vacuum it down and check for leaks first.
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  #3  
Old 06-28-2007, 06:51 PM
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How do I vacuum it down? How do I check it for leaks?

Sorry, I know nothing but the electrical side of AC and not a ton at that.
Thanks!
Nick
__________________
-Suburban '93 220k
-Diesel Jetta '03 350k

Sold
--E320 '95 200k
-E320 Wagon 1994 155k
-300d Turbo '87 187k miles
-E320 1994 200k
-300d Turbo '84 245k (sold to Dan62)
-300d Turbo '84 180k
-300sd '80 300k
-7.3 Powerstroke Diesel 15P Van 500k+ miles
-190d '89 Non Turbo 2.5 5cyl 240k (my first MB)
Tom's Imports of Columbia Missouri Ruined the IP in changing leaky delivery valve O-Rings - Refused to stand behind his work. Mid-MO MB drivers-AVOID Tom's!
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  #4  
Old 06-28-2007, 07:11 PM
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Posts: 10,767
An A/C shop will have to do the vacuum if you don't have the equipment.

I have a sniffer, if there is pressure in the system it will find something like 5ppm, it doesn't sound like you have enough pressure for that method however.

If there's little or no pressure, you have a leak (or leaks). The questions are where and how much does it leak, and whether it's something like an evaporator which is expensive and a 2-day replacement job.

It's probably best to see how bad the hydraulic part of the system is before you knock yourself out troubleshooting the electrical, the electrical portion can IMO always be fixed.

When the A/C works on that car, it is a very good system. Mine blows cold, doesn't overheat in any traffic, makes me happy.

On the electrical side, ... with the A/C switched on MAX, short across the low-pressure switch momentarily to see if the compressor clutch pulls in.

The high-pressure switch should turn on the fan low-speed (if the resistor isn't toast).

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