So I had to drive in the rain and of course I lost both low beams within minutes. I pulled them out to see if they were fixable and the previous owner had obviously wrecked it and put it back together poorly (no liners). The cover was off one and a huge whole cut in the other. Both headlights including both ballast were submerged in mud and water. I replaced both headlight assemblies, ballast, and checked all fuses and relays (all good). Only one of the new ballast worked (checked on both HL to make sure all lights worked). Ordered another one plugged it in and it worked. When I plugged both HL in only one low beam would work. I gave it a day and now the working ballast isn't working. Does anyone know what I need to check to see where my issue is???

 

I would bench test the replacement bulbs and ballasts that you purchased to verify everything works. You can do this with a 12v power supply or temporarily rig something up by using the car battery. If the new bulbs and ballasts work, I would check all of the harness connections. Chances are if they were covered or submerged in mud and water, there is likely some loose or bad connection somewhere in there. Get some electronic parts/contact cleaner and clean all of the connections. Also, verify the fuses are good and use a multimeter or test light to confirm power/ground is coming from the main body harness.

 

Definitely give those harness plugs a good cleaning with some electrical contact spray. Be careful which spray you use, the silicone seals in the harness plugs tend to swell up and cause locking issues if you use something aggressive like brake clean, I've also seen electric motor cleaner that is NOT safe for plastics. For this reason, I tend to use MAF cleaner for my electrical plugs. I would also take a close look at the harness and grounds since the fender splash shield was missing on one side. Road debris sling-shot off the tires could have damaged the harness shielding over time. The engine bay grounds are located close to the headlamp areas as well and could have suffered major rust/corrosion without those shields.
Cheers!
-Icer