This may have been covered already but, Just bought a 02 Blazer that has dim left side headlights (low & High beam) so i bought 2 replacement bulbs and installed them and still have 2 dim headlights on the left.......Passenger side works fine and so do the left side marker lights on the same wire harness.
Where do i start looking ?
The conections at the bulbs are secure and i see no damage to the wire loom......help

Just pulled out the airbox and checked the ground and it was good. Would the relay under the hood go bad on 1 side and cause this ?

 

more than likely your relay is bad or there is too much resistance somewhere in your wiring.

 

Ok cool thanks for the info.

 

Looking at the wiring diagram for a 2002 non-zr2:


It doesn't look like there is anything in common between the two left side bulbs that doesn't also get shared with the right side...

 

Added a new ground wire from the low beam and it still dont work right, i just shut the hood because the wife said i shouldnt be out there cussing at it....lol
So i'm going to add a ground to the high beam side and see if it fixes it because the relay was good.

 

Look at the wiring diagram I posted above. You may cause more problems than you originally had by adding grounds into a system as complex as this...

 

ITS FIXED !!!!! lol

Turns out there is another 15 amp fuse for the headlights in the relay box under the hood.
Now i can start adding my touches to the inside and out, My 97 Blazer was quick and it was a 4x4, This thing is a 4x2 and its a damn rocket ship.....

 

I figured it would be something easy and stupid lol at least it always is with my problems. Glad to hear it's fixed though.

 

Now to tint the windows and find a cold air intake

 

where did you find this fuse? close to the master brake cylinder?