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72 Fleetwood Seventy-Five; 94 Fleetwood Brougham; 06 DTS
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Discussion Starter #1
This week after filling up with gas, I noticed my outside thermometer was very rapidly increasing well past the actual 35-40 degrees it actually was outside. It kept climbing all the way to 190 degrees! Since then, it has read between 120-130 on short trips. I wouldn't really care, except the automatic climate control seems to want to preemptively cool down the interior, so to get heat I have to turn them temp all the way up to 90 degrees to get warm air again. Anyone else have this happen? Any thoughts on the cause and/or fixing it? Thanks!
 

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18 XTS Luxury AWD, 84 Buick Electra Estate Wagon **** Gone - 06 SRX, 08 DTS, 87 Brougham d'Elegance
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Sounds like you need to move to a cooler climate!!! :cool:

Seriously, though ... it's possible that the temp sensor is bad. I had one go out on a 2001 Park Avenue. It would barely change after I left my garage ... whether it was summer or winter. I replaced the sensor and it was fixed.

Before that, however ... I would quickly take a look at your one. It's just a thought, but perhaps it got loose from its bracket and is resting against the radiator. If so, just snap it back into its housing. Free fix if that's all that happened ...

In looking at GM Parts Direct, the Temp Sensor (part 15047946) is $16.29. That seems to be the bracket and the sensor sold as a unit. The sensor is the only part you would need to replace though. They're simple to replace. It is accessible from behind the grille, through the space by the hood latch. Should take 5 minutes.

Hope this helps...
 

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72 Fleetwood Seventy-Five; 94 Fleetwood Brougham; 06 DTS
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Discussion Starter #3
Thanks, I didn't know it was so accessible, or so close to something so hot (seems like a bad place for it, but what do I know!), or I would have checked that first. I appreciate the help!
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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2008 DTS Platinum. gone: 04 Deville, 76 Eldo conv, 74 Fltwd
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Thanks for the info & picture so we know what to look for.

My reading starts wrong and often gets worse before it gets close. The manual says it isn't supposed to change for the first few minutes, IOW when you might want to know.

Now I just need some nice weather.
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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The ambient (outside) temp signal is heavily time-damped to prevent sun/shade/rain/tunnel artificial temp swings. The HVAC system does use that temp as one of the system inputs. There are also at least four air duct temp sensors, a cabin air temp sensor, and at least one sunload sensor, too.

You might also want to locate the cabin air temp sensor and make sure the intake grille, tunnel, and sensor are not full of dust bunnies. If dirty, that sensor will cause all sorts of weird HVAC temp swings.
 

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18 XTS Luxury AWD, 84 Buick Electra Estate Wagon **** Gone - 06 SRX, 08 DTS, 87 Brougham d'Elegance
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You might also want to locate the cabin air temp sensor and make sure the intake grille, tunnel, and sensor are not full of dust bunnies. If dirty, that sensor will cause all sorts of weird HVAC temp swings.
Good point ... I had a whole passel of dust bunnies in mine when I got my DTS.

The intake grille is on the dash ... to the left of the steering wheel and right of the headlamp switch. It comes out very easily and you can use a q-tip or brush to gently clean in there around the sensor.
 

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2008 DTS Platinum. gone: 04 Deville, 76 Eldo conv, 74 Fltwd
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237 Posts
The ambient (outside) temp signal is heavily time-damped to prevent sun/shade/rain/tunnel artificial temp swings. The HVAC system does use that temp as one of the system inputs. There are also at least four air duct temp sensors, a cabin air temp sensor, and at least one sunload sensor, too.

You might also want to locate the cabin air temp sensor and make sure the intake grille, tunnel, and sensor are not full of dust bunnies. If dirty, that sensor will cause all sorts of weird HVAC temp swings.
Yet my 2004 Deville's temp reading was spot on all the time. Driving up the hill to my brother's house in rural CT, the temperature can drop 3 degrees in less than 3 miles. One of these days, I may need to know that STAT, as the TV doctors say.

They also delayed the instantaneous MPG reading, probably so people like me won't obsessively take our eyes off the road to get that extra tenth of a mile.

I hadn't considered the interior sensor might be turning the driver's heat cold like mine does after 20 minutes, so that's worth checking before I worry about how to reach the actuator. Thanks again.

I just ordered me a sensor.
 

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72 Fleetwood Seventy-Five; 94 Fleetwood Brougham; 06 DTS
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45 Posts
Discussion Starter #9
I have no idea what it was, because before I had a chance to check it out, my wife drove it and it was back to normal, and has been reading correctly since! Thanks for the great and useful information, though. I'll probably need it someday!
 
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