Hey guys, well I drove my 94 S15 for at least 30 miles today and I noticed that the voltage gauge is lower than usual, and it tends to jump up and down a little bit, especially after driving for a little bit at a red light (with the headlights on). The lights also dim a little when I blast the fans, same with using the power windows/locks, etc. I'm almost positive that my alternator is going sour but I just wanna double check with you guys in case it's another problem. So what do you think? Thanks!

 

go have the alternator check sounds like that is what it is

 

how do i do that? hook up a voltmeter to it?

 

Yep. It should read somewhere around 14v or at least something over 12.
You can also take your car to autozone or such and they will check it for free.

 

Yeah, or the cheap redneck way (the way we do it) is to start the truck and while it is running, disconnect the battery. If it is a bad altenator then the engine will die cause it won't have the power from the battery to keep it going.

 

That's a good idea, but too bad that GM used those annoying "screw in" battery terminals (or whatever you call em) lol. I'll just have the guys at autozone check it out.

 

You can just take it to advance, autozone, oriellys, whoever you prefer and they will check it for free. You dont even have to take it out they will wheel the little cart outside and hook it up a in seconds you will know. They can even test the battery with the same lil cart.

 

bigjon1, Please never do that to a 90+ model vehicle!!! It may work fine but can actually cause a voltage spike that can fry the delicate electronics in newer vehicles. IE: the computer, sensors, etc.

 

umm.......why would you think the side terminals on a GM are any worse to do than a top post-which was actually the factory style battery terminals on my '90 diesel 'Burb?

i've done this numerous times before (my '98, friends '03 Silverado, my '95 Reagal, another friends '99 Maxima, list goes on), never had any issues.

while i've pulled the battery teminal off while the engine is running, i've never hooked it back up until the key is off, for that exact reason, and i would guess, what you were getting at?

 

old skool luvr, Yea I've done it before in extreme cases and never had a problem. It's just best not to do it though and if you have too do it like you said I would turn the car off before reconnecting the battery.