[Anthonyott99]

I need help ! I just bought a 2002 gmc Sonoma as a project fir my son , everything was going well until the first time I tried to drive at night , the lights are so dim you can hardly see , I’ve checked fuses and the such , tried to repair all the grounds, well tonight I decided to try to ground all four headlights with they’re own ground , but now one side is bright and the other doesn’t illuminate at all , if I disconnect the grounds on the passenger side then the drivers comes back on , but still dim ! Also I have the drls disabled right now but it’s the same with them , and all 4 headlights are on all the time , the dimmer switch doesn’t change anything ?? Any ideas ??

 

[OpalLacod]

First thing to do is verify you have the right bulbs with the right wattage. Could be as simple as the wrong bulbs. (fingers crossed)

I would imagine someone got under the fuse box in the engine bay and did the "all on high" mod. Basically, you bypass the ground switching for the dims and they stay on all the time. I did this on my Silverado because of the lag my HIDs have powering up. THAT was a terrifying first night run... But all mine are run on independent relays now, so brightness and amperage isn't an issue.

I can see where this mod, if done incorrectly, would lower the output of all the bulbs. I would check around and under the fuse box for any evidence of someone screwing around in it before proceeding. Once you get the bright/dim switch working again (2 bulbs each setting) by reversing whatever was done, then we can work on brightness, if it's still a problem.

 

[Anthonyott99]

Thanks , I will check that first thing and get back to you , I’ve also read there is a ground relay for the headlights under the drivers side dash , will check that also , thought it was weird that I grounded all the plugs and one side got bright and the other side went off !