Pulsing lights

I need some help here. My mech doesn't have much of an idea of what's going on. I have an 03 2.4 with 160K. When I start up in the am, my lights' odo, and ashtray light pulse. It is not necessary for me to turn on the lights as the dome light will exhibit the same problem. Battery, starter, and alt check out ok. Anybody else experience this? Thanks.

 

sounds like you have a bad ground somewhere.

 

x2....maybe try pulling the less important fuses to try to isolate the culprit. Do they pulse when the engine is runing and/or off? Try turning the headlights and blinkers on and off, maybe you'll be able to trace where the problem may be coming from. This could be a tough one to track down.

 

as a general rule, pulsing lights indicate a defective voltage regulator, which is usually built into the alternators these days....

might want to recheck that alternator......just a thought.

 

x2...good call, I was thinking of some sort of grounding issue. What if you disconnect the alternator? You should be able to start and run the truck on the battery alone for awhile. In theory, if the alternator is disconnected, the pulsing should stop.

 

Thanks fellas. Been so busy at work that My first chance to check out the Alt. was this am. Doing the easiest thing first, I disconnected the alt and, bingo, the pulsing was eliminated. Reconnected the alt and the pulsing returned. Now to find a good alt. Thanks again.