Headlight switch and alternator problems?

I was out yesterday evening and had a problem with the alternator and headlight switch - I think.

Since I finished reassembling the 5 about two years ago, I have noticed that every time I turn on the headlight while the jeep is in motion it will miss one time as if for a split second all the power to the system had been lost. After that it runs fine and the lights work fine.

Coming home last night, I switched on the lights and the alternator light came on and stayed on. The Alt light goes out when the lights are turned off.

It's got a new HL switch and a fairly new alternator.

Any thoughts on what the cause might be? A short or ground issue?

Not sure where to start looking.

 

might be a ground. also, have you tested the output on the alternator?

 

I always ground the alternator using a dedicated wire from the alt to a common ground point. Without it the only chance your alt has to find a ground is through the mounting bolts to the bracket to the block. Lots of places to lose or get a weak ground due to grease, rust corrosion, etc. Worth a try, it's quick and easy to do.

I also ground the starter case directly to battery, ground distributor, front shell, and body. Redundant grounds never hurt, especially on a jeep. Clears up a lot of oddball problems, goofy blinkers, etc.

 

If you are having pblms with your gauges also, the speedo group has lost ground at dash panel or panel ground bad to tub or tub to frame or frame to battery. (or all of these) Symptom on alt light comes on, is due to back feed. Cause---Bad Ground.

 

Thanks guys. You have helped me develop a plan of attack.