Electrical Question for Dim Headlights
 

Hello Peeps,

Got a question and not sure where to turn.

My headlights are dim, when I rev the motor they get brighter, at idle they go back dim.

I thought it may be a grounding issue so I changed the battery ground and added a better ground to the headlights.

so Im clueless at this point....

Im sure its an easy fix except Im not that knowledgeable about it.

I appreciate it,
John

Re: Electrical Question for Dim Headlights
 

Check battery voltage at idle - sounds like alternator is not putting out at idle.

Re: Electrical Question for Dim Headlights
 

Will.defintely try that...Thanks so much

Re: Electrical Question for Dim Headlights
 

You may want to install a couple of relays up near the voltage regulator / horn relay. Taking power directly from the alternator/generator to the relay will eliminate the long run to the headlight switch and the high beam switch. Do a search for "headlight relay" on this forum - you should find several wiring diagrams for the relays. It made a big difference with my headlights.

Re: Electrical Question for Dim Headlights
 

I remember having that same problem on my truck. After I put the headlight relay harness on, I think that issue went away, but I'm not remembering for certain if that's the case. Since I'm not remembering correctly, maybe that means the relay harness fixed that for me.

If your truck doesn't have a relay harness, definitely add one. They aren't too expensive, easy to install, and well worth the money. The stock headlights in my truck got way brighter with the relays. One of them burned out a couple weeks later, but then I was able to swap to some halogen bulbs which were even better. At the moment, my c10 throws better light than my 95 Dakota. Apparently, Dodge didn't start using headlight relays until some time after 1995, so that'll have to get fixed at some point too :lol:

Re: Electrical Question for Dim Headlights
 

Too many places to lose voltage on the power side of the circuit. Relays should solve that problem

Re: Electrical Question for Dim Headlights
 

For your year truck here is a great thread with great ideas on how to do it along with many links on the subject. http://67-72chevytrucks.com/vboard/s...d.php?t=397695

Re: Electrical Question for Dim Headlights
 

Thanks for the info guys it is greatly appreciated....I will be re-wiring the entire truck in the coming weeks and the relay seems to be the key to headlight function...I think Andy used these on his truck as well so I will definitely be adding these to mine.....brighter headlights are definitely a plus

Re: Electrical Question for Dim Headlights
 

My 75 had that problem. Switching from the 10SI Alternator to a 12SI fixed it. The 12SI puts out about 7 amps more at idle then the 10SI.

If you are still running an externally regulated alternator, swapping to an internal regulated when you do the re-wire might be a good idea. BTW, the internally regulated 10SI and 12SI both use the same connectors.

Re: Electrical Question for Dim Headlights
 

check my FAQS in the threads at the top of the electrical forum page.

Re: Electrical Question for Dim Headlights
 

You have some real good replies here. Also check the battery. A bat. getting weak can cause that also.
George