Intermittent A/C problem

STEPHEN SIERRA

MEMBER
1995 BMW 525I
2.5L
6 CYL
2WD
AUTOMATIC
205,000 MILES

Received last minute discount of $500.00 because A/C was having intermittent problems. A/C would come on and off until it stopped entirely. Made it through the first summer but, starting to get hot here in Texas. I've searched many possibilities including fuses, relays, replacement of climate control. None worked until by accident, I added (100%) coolant to radiator. Car had always run cool so I never added or checked. It seemed low upon looking down into the reservoir. I added only a pinch and went to the store to purchase distilled water to add more. While driving I tried the A/C and it worked again. While coming down from a feeling of pure euphoria, it dawned on me that this German monstrosity could run better with a little coolant and water. Compressor turns on and off just fine now.
Could this have been the whole problem from the beginning?

3 Replies

DANNY L

MECHANIC
5,648 POSTS

Hello, I'm Danny.

I must say, In all my years I've never heard that one! The cooling system doesn't really control the A/C system. Low coolant will affect the heater performance but should not the A/C. I suppose you should just continue to monitor and get back to us should the problem arise again. Hope this helps and thanks for using 2CarPros.
Danny-

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Sunday, June 16th, 2019 AT 3:38 PM

STEPHEN SIERRA

MEMBER
2 POSTS

Thanks Danny, My hopes were up prematurely. Problem still exists but, with a new twist. At Lowe's the other day, just about to go inside, my A/C blower is on speed 4, everything stops and blower goes dead. Originally, A/C goes in and out, then doesn't work for awhile, then goes back to intermittent in and out again, now blower goes out.
Checked it before going to work today. Number 19 on the main fuse box(30 amp) is burned up and slightly melted. Put backup 30 amp fuse in and blower works again for now. It's a ten minute drive to work, five minutes in and a/c stops cold and warms up.
What I know is. When a.C. Blows cold. Defroster light will work. I'm assuming (pretty sure) defroster will run also. When A/C blows warm I press defroster and defroster light does not come on. All the while, A/C light and recirculating light come on when I turn knob to speed 1, 2, 3 or 4.
Not sure what's going on but I'm thinking your suggestions will be to open this baby up and look for shorts?
Thanks in advance.

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Friday, June 21st, 2019 AT 6:55 PM

KEN L

MASTER CERTIFIED MECHANIC
48,363 POSTS

Hello,

It sounds like the climate control module is going out. To confirm here is a guide to test the power and grounds to confirm the failure with the wiring diagrams for the AC and locations below:

https://www.2carpros.com/articles/how-to-check-wiring

Check out the diagrams (below). Please let us know what you find. We are interested to see what it is.

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