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Cadillac Repair/1984 cadillac deville headlights kill car when turn on


hello my 1984 caddy deville just been robbed for its cd tv player in dash and i got it replaced. i notice when i drive at night ill turn my headlights on and the idle of the car will drop and then the car will just die. it drives like a champ when the headlights are off but when they come on the car power becomes weak. i could drive the car with lights on but its weak and if i stop at a red light it will just die. but turn on without a problem. i have a new battery.


Don't know if your new system is drawing more, but will tell you it's time to check alternator output. With headlights on battery is going below 10 volts causing engine to stall. Should have 14.2 voltage engine running and everything on. Also have amperage output checks as well. A new alternator will take care of your problem as long as battery negative frame ground is good.
Let me know how it works out. Alternator not related to theft.


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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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