Electrical issue

[Sonicman]

I've been noticing that my new head lights and dash gauges will go from reallly bright to dim and back while driving. The heater fan changes speeds at the same time the lights are going from bright to dim.

I know very little about electrical stuff. I do know the battery, starter and alternator all have less than 400 miles on them. I assume the voltage regulator is the original. The truck is a 69 c10 half ton 2wd with a 250 L6.

[VetteVet]

Sounds like a bad ground on the negative battery cable, a poor connection on the positive cable or the regulator is failing. when the battery voltage can't be sensed by the voltage regulator it will cycle between full charge and no charge, causing the lights to go dim and bright.

What lights did you install? If you have the stock alternator you need to upgrade to a higher amperage internally regulated one.

[Sonicman]

I put in the euro style from LMC. I replaced what looked like the original headlights which would just barely light the road. I will clean all the terminals and replace the voltage reg. first. The alternator I got at O'Reily's is the stock replacement. What kind of alt. should I get?

[cdowns]

ground connections from headlight to rad support,rad support to frame,battery to frame,alt to motor,motor to frame// also voltage regulator ground to the rad support
r all very important

[Sonicman]

Thanks. I just rebuilt my engine and rattle canned the engine compartment while the engine was out. I didn't clean any of those areas up like I should have. This my first ever rebuild so I just learned a very valuable lesson........ALWAYS clean your ground connections.

[VetteVet]

You might be able to get by with the system you have if cleaning the connections helps but when you start adding accessories like high wattage lights and cooling fans and stereos, the stock system just won't keep up. Do you have the charging light (idiot) in your dash or the ammeter. If you see the light come on while the engine is running or if the ammeter is flickering then you definitely have charging problems.

Go to the electrical forum and read some old posts about alternator upgrades and you will see how to improve your system. Make a thread if you want and we'll get you some answers. This thread will disappear by the end of the day because so many guys post on this forum yours will be on page two by tomorrow. After you clean your connections, let us know how it worked and if that fixed the problem.