dim headlights

[85redrunner]

on my way home from work this mornig i noticed my headlights were not working very well, they were very dim and i had to use my brights just so i could see, they were also dim, i dont think its an alt. problem because everything was working fine, foglights interior lights etc.i have hella H4 headlights with 55w/100w bulbs in them and they are usually extremely bright, so if anyone has any ideas of what could be wrong besides the alt. id like to hear them.

[Dobi]

If you're certain its not your alternator, may wanna make sure they are grounded well

[drewbond]

I would check the connections them selfs on the blubs, but I would think it would more likey be the switch or the power going to the switch since both normal and brights are dim.


If you have a multi meter you can save your self some time. With battery disconnect, and headlight switch on, check the resistance between positive battery cable and head light connector, only one will have continuity, then check other head light, then change to brights, do the same, then check resistance between ground connection to battery, and the last wire on the headlight connection. The main goal here is you will find one with higher resistance then the others, and hopfully not all of them.

If that becomes too much of a PITA, you can upgrade the headlights to be controled by relays, then the power for the headlights is not going thru the switch in the cab.

I can make the wiring diagram to do that if you like.

FYI: For every volt lost the lights will be 25% dimmer

[85redrunner]

hey thanks for the replys, i pulled the bulbs out to see how they looked and it turns out they were both fried, i dunno why, anyway i rplaced them and everything is working fine, now i just gotta wait ad see if these ones do the same thing.