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Registered
1990 DeVille
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181 Posts
Discussion Starter #1
The blower control works fine.

In AUTO mode, however, the compressor stays on. In a few minutes it gets very cold and must be switched to ECON for a while.

Where is that thermostat, and can it be serviced? If not, where do I get a working one?

Or could it be a stuck relay? If so, where is it?

Thanks
 

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Super Moderator
White Diamond '03 DHS (with DTS floor shift)
Joined
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87,099 Posts
Start by pulling the DTC's.

The "thermostat" would be the in car temperature sensor or aspirator. It is located behind a 1" square grill somewhere on the dash. It may or may not be the problem.
 

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Registered
1990 DeVille
Joined
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181 Posts
Discussion Starter #3
THANKS

There are no stored codes.
I now have a service manual, but the climate control information is scattered in several locations. I had hoped that this was a common problem.

The circuit cannot be too complicated: a sensor, and a controller that includes a means for comparing sensor data to controller input, and a relay that applies power to the compressor clutch.

But the relay can't be stuck because the compressor clutch is not engaged when the system is in ECON mode. So it should be the sensor or the controller (that module in the dash). Does that make sense?

I'll keep searching in the manual...
 

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Super Moderator
White Diamond '03 DHS (with DTS floor shift)
Joined
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87,099 Posts
The sensor would be the more likely culprit in my estimation.
 
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