Tugs

My drivers side headlight on my 89 4x4 pickup is like a real dim dull yellow color when it is on high or low beam. I switched the bulbs same results so I ruled out the bad bulb. Does anyone have any suggestions? The passenger side works fine.

RAD4Runner

Assuming your wiring is OK, a busted fuse on Driver's side would cause that. Side with busted fuse would not go all the way OFF but get dim.
Explained better with a schematic below.

The way Toyota wired it, when you put it in low-beam, some current (pink in schematic below) from good side will flow through the supposedly "unused" high-beam filaments of both bulbs to the filament of the side with busted fuse. Side with busted fuse will have lower voltage across it, so it will light up but dimly.

When you put it in high-beam similar thing happens, but this time "leakage" current will go through the supposedly "unused" low-beam filaments.

The supposedly unused filaments where leakage current flows through would actually glow, too but hard to notice.

Tugs

Thanks I will check tomorrow this sounds like exactly what's happening I will let you know how it turns out.

Tugs

RAD4Runner That was it replaced the fuse and it works now Thanks!

RAD4Runner

Cool, Dude! Glad it was that simple and am happy to help.

My94yota

Very cool, I was going to say a bad ground or something but thats not the first time ive seen power backfeeding like that, good call tho