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Cadillac Repair/1999 Cadillac Deville Alarm

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Expert: - 11/4/2008


Question
My alarm will go off for no apparent reason and I have even had my radio come on will  all doors locked. To avoid the security system from working I now lock my car by key, turning the system off. What might  be causing the alarm to activate? The radio to activate?

Answer
Hi Tom,

I am an expert in the ignition anti-theft systems. Factory alarms in many cases require hands on diagnoses in most cases, but I will throw you some thoughts. Please keep in mind that I have not worked on the factory alarms for many years, but Cadillacs were common to me.
What throws me off is the radio going on with the doors locked. The radio going on may be a separate problem with the retained power with the doors closed. To my knowledge, the radio is not even wired to the factory alarm.
A dome light circuit problem can cause the problem. A door pin switch could cause falsing. Some GMs ran shock (impact) sensors in them as well and that could be too sensitive. The sensor was commonly found in the trunk. It could be a bad module as well.
I wish I could assist you better, but without seeing exactly what is happening to the vehicle and how often this problem happens, a forum like this is just good for suggestions.

Thanks, for the question.

Rob

Cadillac Repair

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Rob Painter

Expertise

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?

Experience

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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