Climate Control Channel 11 (alternator voltage)

[Frank Stadmeyer]

Phil,

I've got 2 T44's that have the same symptoms and the A/C doesn't work 
on either.  I'm getting rid of the'89 100q and I've given up trying to 
fix the A/C on the '91 200Q but tomorrow I'm going to try to jumper 
across the A/C low pressure switch to see if this is indeed the case.

Frank

On Aug 21, 2004, at 8:07 PM, Phil Rose wrote:

> Well, now I'm convinced: An open circuit at the A/C low-pressure 
> switch--caused by low refrigerant pressure or disconnected 
> connectors--will cause the readout from Climate Control Channel-11 to 
> be stuck at a value of 12.0 (Channel 11 reports alternator voltage).
>
> A little history: Last summer I had the A/C system converted to R-134 
> and consequently had the A/C working for the first time since we've 
> owned the car. Soon afterward I noticed that the CCC-11 was 
> mysteriously functioning properly--showing a variable alternator 
> output voltage--rather than just the steady "12.0" value that we'd 
> previously always had (with this car). At the time it was just an 
> interesting coincidence, which I posted about last summer.
>
> After a while, A/C system leakage caused the refrigerant pressure to 
> fall so low that the A/C quit (with the low-pressure switch in an 
> "open" condition, according to the CCC-17 diagnostics). And 
> coincidentally, when I next checked the CCC-11 value, it had again 
> become frozen at "12.0". Yesterday I finally got around to recharging 
> the A/C with a couple of cans of R-134. After the A/C began working, 
> guess what also happened: Yep, channel 11--simulauditaneously--was 
> back in normal operation. I imagine there might also be _other_ 
> situations that can cause CCC-11 to become stuck at a value of "12.0", 
> but now I'm  certain that an open-circuit at the A/C low-pressure 
> switch is one cause.
>
> Phil
> -- 
>
> Phil Rose				Rochester, NY USA
> '91 200q	(140K, Lago blue)
> '91 200q   (64K, Tornado red)			mailto:pjrose at frontiernet.net
>
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>


Frank