My voltage has been slowly dropping as i've run my 4runner over the last week until it is so low the starter won't turn the engine over. So i'm wondering if the battery is not holding a charge or if the alternator is starting to go. My past experience w/ alternator's and batteries has been sudden catastrophic failure so i'm wondering if it is something else. Also when I turn my turn signals on the volt meter starts moving w/ the turn signals...I know this is a clue but i'm not much of an electrical guy so i don't know what it means.

 

Charge up the battery. Fire up the truck. Disconnect + lead from battery. If engine continues to run the alternator is fine. If it dies.......
Time for a new alternator.

 

How is old is your battery? If it is very old, that might be a clue. I recently had similar symptoms with my car. It would take a while for the battery to go dead. I could charge it up and it would last about a week, but eventually it would go dead again.

Taking a chance it was the battery (since it was ~ 5 years old), I replaced it. It turned out it was. I have never had one do that before.

 

Could also simply be a bad battey connection; check that first. Remove both clamps, clean terminals & posts & reinstall. WHile you're at it, check all your engine/body grounding straps. These are common problems as vehicles age; connections rust/deteriorate with time.

 

thanks i didn't think of that

 

I may be lazy but take it to auto zone and they can check all of it there.

 

Check both batterey leads, I replaced a battery, pulled and bench tested the starter. I cleaned the terminals too. When I checked the leads there was corrosion an inch down the wire in the isulation.

Lesson learned: Start with the cheap stuff first

 

it looks like the ground straps just needed to be cleaned up....it seems to be working good now.

 

always a good idea to try the cheap things first