Ok so on my 87 Iroc. One of my headlights seemed dimmer then the other. I went and purchased to new headlights and still have the same issue. I tried to adjust it and it didn't help. I am starting to think that it could be a wiring issue. Not really sure why one is brighter then the other. Any help is appreciated. Thanks

 

Check the voltage across the terminals, and then again to ground and compare the difference.

 

Ok so I checked my voltage and compared them and they are both pushing out the same voltage. I'm not sure why there is a difference in brightness.

 

I feel bad for not clearly specifying what I wanted you to do, and most likely the results show it.

Testing should be done with headlights connected to plugs- this helps to see if the problem is related to the load that is applied.

Voltage checks should be across the plug and then again to ground- this helps to see if it is related to grounding applied to the connector.

In my opinion, OEM wiring is a typical cost vs benefit loser. Many OEMs use the lowest gauge of wiring and we get marginal lighting when new. A few years of oxidation/corrosion puts the lighting well below par. SAE spec lighting does not help

One of the first things I do to my vehicles (after seafoam / tuneup / fluids) is to get eCode lamps and throw relays into the wiring harness for the headlamps.

Linked Article: Third Gen Headlight Upgrade

Linked Article: Daniel Stern Lighting- Relays

 

I will try that. I tried it with the headlights disconnected from the plugs. I'll let you know what it is as soon as I get a chance to do it. Thanks for your help

 

check to make sure it has a good ground. ive seen plenty of times one headlight dimmer due to corroded or poor ground connection

 

Both true statements!
I'd also get some DeoxIT to spray on the power and ground straps along with sockets and connectors. It's a highly successful solition that professionals in the electronics field use all the time.
Because my junk was so bad I sprayed a lot of heavy duty electrical contact cleaner in my plugs and sockets. Once they dried out I followed it up with DeoxIT D100.
My headlights, tail lights, turn signals, and side markers were only brighter when brand spanking new. It's kinda spendy and comes in a real small can.
A lot of local places will not have it and some will probably have never heard of it. Too bad for them.