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Cadillac Repair/79 deville lights and locks


   i recently purchashed a 79 deville that has been garaged its whole life and was well maintained, so everything was in working condition. unfortunately the battery went south, i left a 2 amp trickle charger on the car for several hours but i did not unhook the battery. when i tried to start the car it fired right up with no problem. soon though i could smell that familiar smell of fried electronics permeating somewhere from under the dash. i soon noticed my domelight and power locks were not working and that the courtesy lights under the dash by your feet would not shut off so i was forced to remove them. i checked fuses and nothing was burned up? nothing else strange was noticed during a visual. they packed a lot of strange options in these cars and there is wires in abundance so i was hoping to get knowledge of a good starting point. anything helps and thanks in advance!!
         kenny b

Hello Kenny,

The dome lamps, cigarette lighter and locks are on the same fuse.
As for your courtesy light being on, it can be one of two issues. Either a feedback situation form the dome or more commonly a bad door jamb pin switch. Push the plunger in on each door (one at  a time to see if the courtesy light goes out. If not, you will need to replace the faulty one.

Also be sure that your dash light dimmer dial is not on to turn the courtesy light on.

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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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