Hey guys, have a little problem with my 1996 blazer. The lights "pulse", so to say. I checked the alternator, and battery. Battery wound up reading weak, so i replaced it. Well, still the same thing is happening. Now i am thinking it has to do with a bad ground connection. Maybe i am wrong. Thanks for any help.

 

Pretty common problem, usually it means the alternator and or voltage regulator is on its way out. Some of the auto parts stores will check it for free, but keep in mind you get what you pay for, and their testers are not 100% reliable.

 

Cool thanks. I had the alternator checked already, they said it was good. Guessing i will look into the voltage regulator. Great. Lol

 

Who tested the alternator? Was it a shop or a parts store?

The regulator is controlled by the PCM on your vehicle. Although it's rare, it's also possible there's a problem with the PCM or wiring. The voltage regulator is inside the alternator so it requires disassembling the alternator and sometimes requires desoldering the old one and soldering the new one in. The option is replace the alternator, (it comes with the regulator) IF that's the problem. Best to have a qualified shop check it out.

 

I had Advance auto throw it on their machine. Is their machine not reliable? I will go to a chevy dealer of need be. It is killing me having these lights "pulsate". Lol
Thanks for all your help too, by the way. Greatly appreciated.

 

Those machines are good for the basic tests, (regulated voltage and maximum amperage output) but they fail miserably at detecting the type of problem you're describing.

 

Awesome, i will take it to a dealer. Report back what i find. Thanks again man.

 

Yeah those auto store testers will a altenator or battery is good even if barely passes the test.Just in case it is a ground trace your ground wire from your battery to where it bolts on the frame and check that connection for loose connections or corrosion

 

mine has pulsed slightly for a couple years now. im sure its the alternator, but it still charges fine, and im cheap

 

Just curious, does it do this when your heat is on, When I turn my heat on, or blower motor for that matter, on anything but low, my interior lights pulse, if its on high, my headlights do for about 5 seconds.
I am just too lazy to clean the ground for the blower motor on the firewall. Just an option.