Hi guys, my sister has a 92 Toy. 4-Runner and she's been having this problem all week maybe you guys can shed a light on the subject. The interior lights pulsate when the car is running, as well as the dash / inst. cluster lights and doors/dome lights. It's like they are loosing power, and regaining it - just over, and over again. Could this be an Alternator problem or voltage reg.? They don't seem to change (as far as the pulsating goes) from reving to idle speeds... Tested voltage @ the battery and it reads 14v but when I run the meter on the interior stuff, the voltage seems to be going from 13.5 - 13.8 or so and not staying consistant.

Thanks for all your help

 

but if the engine is off, everything is steady?