Okay I have a bouncing volt gauge that has been increasing in frequency until last night the truck looked like an EMS vehicle with the head lights on. Pulled the alternator and took it to a good local shop. They bench tested it and came up with a bad rectifier. Replaced it and re-installed. ($50 instead of $140 plus core charge at Advance Auto.) Lights are brighter but the volt gauge still bounces. Any thoughts? Could it be a issue with battery cables? Kind of a stumper and more annoying then anything else at this point.

This is a great sight........with great people. Spent so many hours reading threads my eyes are crossed.

 

I would bet its the glow plug relay switching on and off. They don't usually do that so I am not sure why it would do that.

 

Have you checked the connector and wires of the upper rear part of the alternator?

 

231k on truck w/ original GP relay. GP's replaced at International dealer around 100k. Been thinking about replacing both again. Concerned with not being able to remove them and getting into a "remove the head's" situation. Ohmed them out this summer and 3 are reading bad.

The plug on the alternator appears tight and has the di-electric grease in it yet. The single wire jumping from the middle of the 3-wire plug is a little loose in it's plug. If I replace the entire plug......is it as simple as cutting it off and weather tight butt connectors to install new one? That would be WAY to easy a fix! lol

 

fire up the truck and wiggle the wire, if the lights flash as you wiggle the wire you have found your culprit

 

The lights flash / gauge bounces at idle and increases frequency as load / rpm increases. I will check the wires though. Maybe wiggling them it will stop...same affect and problem located. Also going to stop at the rebuild shop and let them check the alternator / wiring. One of those places where looking at the shelves I'd guess he has every alternator / generator / starter part ever made.

 

Mine did that and i just started cleaning all the grounds i could find not sure witch one fixed it but it was fixed when i was done