OK I am noticed last night while sitting in my truck in my driveway on the phone that my inerior lights seems to slightly dim or flicker lightly. I also noticed the headlights had a very slight dim or flicker to them . Anmy ideas? Alternator?

 

I'd get a voltmeter and check the voltage at the battery posts while the engine's running and you're experiencing the flickering. You should see a fairly steady voltage between 13.4 and 14 volts. If it's fluctuating a lot at the battery posts, then I'd check the battery connection on the output post of the alternator. If it's tight, then I'd take the alternator to have it tested.

 

Good idea. It could very well be just that. I just had both baterries replaced a few weeks back. Do you think it could be bad battery cables?

 

Did you clean the post connectors on your cables when you replaced the batteries? A post cleaning wire brush is pretty cheap and it might be worth a try cleaning your posts and cable connectors. After doing that, it's also not a bad idea to spray them with some anti corrosive spray or give them a thin coat of vaseline or wheel bearing grease to keep them from corroding.

While not impossible, it's highly unlikely that you'd have bad connections to both batteries at the same time. I'd check with a voltmeter at the posts of both batteries. If you're experiencing the flickering and seeing about the same voltage fluctuation on both batteries, then I'd suspect the alternator or another problem. Somehow I doubt that the battery cables are your problem unless they're really badly corroded.

If the voltage at the batteries is fairly steady at the batteries and at the alternator output, then you may have some electrical load in the truck that's cycling or a bad electrical connection that's making the lights flicker. I had a Suburban that was doing some strange things and it ended up being the connector block through the firewall to the fuse panel.

BJ Lexington, KY

 

Thanks WHJCO!