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Cadillac Repair/heater problems


QUESTION: my heater on my 1996 Cadillac concur deville keeps going out while i am driving, if i have it on 90 degrees, it keeps going down to 75 and nothing is working but the fan, no heat,no defrost, than everything on the screen goes blank, including the gas information, the speed information, the trunk button does not work and neither does the gas tank button.then all of a sudden a the theft system problem comes up and it tells me the the speed has been reduced to only 90 miles, when i stop and put the car in gear my headlights stay on and the park,neutral,drive and 321 information starts to flash. can you please tell me what is going on?

ANSWER: Hello,

Unfortunately, without being at the vehicle with a tech II programmer, it is hard for me to say.
You could have a bad Body Control module that operates all of this or it could be a simple a a loose ground.
The first thing I would tell you to do is go to the battery negative cable. Uscrew the bolt from the end that goes into the frame. Scrape everything to bare metal and tighten bolt.
If that does not work, you will need to check all grounds under the dash on the driver and passenger side.

Good luck!

---------- FOLLOW-UP ----------

QUESTION: where is the body control module located, and is there anyway you can send me a picture of it?


I spent close to a half hour searching for the answer to your question as to the location of the BCM on a 1996 Deville. I found nothing but bonehead answers and I sure do not remember on a specific component location of an 18 year old, repairing just about every make model and year one could think of.
However, I don't want you replacing a perfectly good component on a guess and not repairing your problem. The only correct and accurate way to diagnose and repair anything on this vehicle is to obtain only a Cadillac factory service manual. Flow charts will walk you right through this in the manual.
You should be able to purchase a Factory service manual for this car on Craigs list or Ebay.
That is why I told you to check all grounds first. Generally if there is a problem with the BCM it is absolute and does not operate intermittently.
Cadillac dealers are good for replacing parts on a guess, of course with no guaranty and seldom repairs the original problem one brought te vehicle in for.
Guessing on computerized vehicles is just a waste of time and money.

Good luck.


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Rob Painter


Alarm system questions cannot be answered on this forum. These systems are not what I can answer. Without being physically at the vehicle and not knowing what kind of electrical service has been done on the vehicle, there is no possible way to give an accurate answer over the internet. My expertise is in Ignition/key based anti-theft systems. These issues include GM VATS (resistor chip in key blade) PASSLOCK (MRD)-ignition lock rotation based, no special ignition key and the PKIII Transponder (computer chip in key) systems. These systems are not alarm based and are integral with the starting of the engine. This is why I cannot diagnose alarm problems without physically looking at the vehicle: Alarm systems are a completely different annimal than ignition key/lock based anti-theft system. Many alarm questions come from vehicles 10 years old, and since older, many hands that had been involved over the years.I am an expert in all GM factory (ignition/key based)systems. Alarm system questions pose to many situations beyond my knowledge as to what has been done to the vehicle over the years. Some guy may have actually wired the stereo into the alarm system. Who knows? Over my past 30 years in vehicle wiring repair, I have seen unbelievable wiring disaters done by guys that consider themselves "mechanics." I have seen stereos and alarms intalled using surgical tape. I have seen modules burn up, un-fused circuits, wiring jambed between the doors and even lamp cord used for a starter kill. To answer alarm questions over the internet without examining the vehicle is like asking; What does it take to remove a dent?


Education/Credentials-ASE certified. 11 years with a GM dealer and 17 years with a repair facility dealing with only the repair of theft recovered vehicles.

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