When driving in the dark I noticed my lights (headlights & dash lights) dimming slightly for several seconds and then they would go back to normal. Then I also noticed the A/C fan would change speeds slightly (slow down) at the same time then go back to normal at the same time the lights did. It now happens long enough for me to do a "systems check" and the electrical says “OK”. It used to happen mostly when the truck was cold or merely not warmed up. Now it happens pretty much all the time. I suspect it is happening day and night, and I only notice it at night when the lights are being used.

I recently had to replace my battery because it wouldn't hold a charge (even at the truck was while they were cleaning it with the doors open and the dome lights on) and thought it was a bit peculiar because the truck is not that old and in like new condition.

Because of the cost of an alternator, I don't want to just change it if it’s not the problem but I'm concerned it may ware out my new battery sooner or leave me stranded somewhere.

Any suggestions?

Thanks~
Tim

 

Try cleaning the battery terminals and the wire connections for the battery off. I assume the terminals on the battery are fairly clean since it is new, but the wire connections may have corrosion on them that could be causing the issue.

If you suspect you alternator is going bad, while the engine is idling disconnect either one of the battery cables. If the truck stays running your alternator is fine. Be sure to clean the cable connections and terminals before you do this to make sure that is not the issue.