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Discussion Starter #1
My 99 STS air conditioner wouldn't come on 2 days ago when I hopped in it after work. I drove about 5 miles down the freeway, all the while messing with the controls trying to get it to come on before I pulled over. Popped the hood to make sure the belt was still on (I know, I know), didn't shut the engine off, but when I got back in, it came on. Today same thing, except after about 2 miles of driving it came on without me messing with anything.

I also have a high pitched "squeek" that has been occurring randomly for the last year under light acceleration, usually around 30 mph. Now the damned thing is driving me nuts!!! It occurs randomly as before and also every time you suddenly step on the throttle, it doesn't have to be a lot of throttle just any jerk of the engine. It almost sounds like two pieces of rubber moving against each other, its a short squeek and happens anytime I want it to happen or at times, as I said randomly.

Could these two problems be connected? Any thoughts?

PS. I replaced the front engine mount recently which was bad, again, but the noise was there before and after the replacement.

Any help appreciated!
 

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1992 STS / 2005 MB G500 / 2003 STS / 2006 XLR-V
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11,694 Posts
Pull the codes and let us know if anything HVAC related comes up.

The squealing may be related to your A/C issue if there is some sort of slugging or clutch issue causing the belt to bind, or some other belt related issue wreaking havoc with the compressor.
 

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1993 ETC, in Windsor, Ont.
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Yeah, sounds just like a slipping belt, might be glazed, or have oil on it. Easy way to tell is to buy some of that belt "no slip" stuff... you spray it on and it tacks up the belt. If that fixes the problem, then you need a new belt! (I don't recommend using the stuff as a fix, even though it does work...but I use it as a diagnosis only 5 bucks is cheaper than 40 for a belt)
 

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Discussion Starter #4
Thanks guys, great suggestions (even though I'm embarrassed I didn't think to pull the codes before I made the post).

Codes thrown are DIM B1324 and DIM U1255. I think that somehow refers to the Dash Integration Module? Any more clarification than that from anyone?

I'll pick up some spray for the belt today and let you know if thats the problem. If so I'll replace the belt this week and be a happy camper.

Thanks!
 

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Discussion Starter #5
DIM U1255 = Class 2 Communication Malfunction (Serial Data Line Malfunction)

DIM B1324 = AC refrigerant overpressure

Any idea whats going on here?

Thanks.
 

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Over pressure probably means the condensor needs to be cleaned. Check it to see if it is plugged up with bugs etc. Wouldn't hurt to clean it anyways.

Dan
 

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Discussion Starter #7
"Over pressure probably means the condensor needs to be cleaned. Check it to see if it is plugged up with bugs etc. Wouldn't hurt to clean it anyways."

Hmm...Interesting, I'll check it. It actually began throwing this code before I turned 50K miles (now have 72K). I ignored it because I never had any problems, clearly not a good idea but I'll check it out today.

Thanks.
 

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2000 DEVILLE,2001 STS.
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Overpressure can also be caused by a malfunctioning condenser fan or the relay that controls it. Just something else to check out while your into it.
 
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