the lights keep flickering!!

[John G]

I am at a complete loss. The lights on my 93 EB just keep flickering. I bought a Haynes repair manual and I did the tests. I added a #6 gauge wire from negative battery terminal to ground. Didn't work. I checked the impeadance between the A and the F terminals on the regulator with an ohm meter. It reads over 5 so that means it is ok. I cleaned the battery terminals and the starter relay terminals. Didn't work. I cleaned the terminals on the alternator. Didn't work. I disconnected the large connector wiring harness from the alternator and the little single wire connector and started the truck up. The lights stopped flickering but of course my volt meter was showing that the battery was discharging. Does that mean the alternator is bad? There are no alternator repair shops around here. Anywhere I bring it the same thing will happen. They will just start replacing things until it stops. They will start with a new alternator, battery, cables, etc... I wish I could figure it out myself because if it is the alternator; it is a really easy job.

 

[dogfriend]

Are the lights just flickering at idle, or at any engine speed?

Also, with everything connected normally, do you get about 13 - 14V at idle?

I think that your test with alternator disconnected means that it is probably the cause. I would try to find one of the auto parts places that can bench test it for you. Usually they can do this at Napa, Autozone, Kragen (Checker on east coast?)

The other problem that might cause something like this would be a bad ground connection, either in the charging system or in the headlight circuit , so I would check all of the grounds to make sure they are ok.

 

[mrboyle]

It sounds like one of the diodes inside the alternator is going out. Your best bet would be replacing the entire alternator with a rebuilt one.

 

[John G]

they flicker at idle. For the first 15-20 minutes after starting up, all the lights flicker all the time and they flicker less the more the rpm's are increased. After around 20 minutes, they only flicker at idle. It probably is the alternator. I just wish there was an exact way to check.

 

[Bill Kemp]

John, most of the auto parts places, at least around here, can & will test the alt on the veh. for free.
Just drive up and ask.
Good luck...