Headlight Ground-Wire Issues (YAY!)
 

I've got a mysterious problem with my Supra's headlights.
We can't seem to find the ground wire to it. I understand the ground wires are supposed to be marked in white with a black stripe.

More specifically, I have taken my driver side headlight out of its housing and I stare at the headlight plug. The headlihgt plug has three female ports that connect into the bulb, of which I'm guessing one is regular lights hot, bright lights hot, and ground. But which is which? They are all reading hot, no grounds.

The Chilton Manual Diagram isn't being a great help, and we can locate a ground wire for EVERYTHING else in the car BUT the headlights ground.
Can anybody maybe give me more insight into this? Maybe where I can find a better diagram than the Chilton's? Maybe even a physical diagram because we are having trouble locating the headlight ground wire with the logical diagrams out of the Chilton. Thanks bunches.

Ok after studying my repair manuals wiring diagrams ive come up with this..There is no (WHITE and BLACK) wire in that system..There should only be a (RED),(RED and WHITE),and a (RED and LIGHTBLUE)..It is the (solid RED) wire that is your positive..The Other 2 are both grounds while on high beams..When you have on just the low beams then the ground is (RED and WHITE)..But the other may stay energized aswell like a positive..When testing make sure that you are using just the (RED) wire as you source and then check the other 2 as a grounds ..You may also pull the harness apart and make sure that some one hasnt upgraded you headlights to a different plug style like for Halogen lights..They did mine and i would have never found out if i wouldnt have rewired my fog lights..If you still have problems let me know..

Sorta fixed, for now
 

Just wanted to give you a reply, since you were nice to keep up with me ^^.

Finally just gave in and took the supra to a recommended shop around town. THey said that they could not find the ground wires from headlights to harness so they just offered to install a new swith in the supra for 150, with 3 mnth warranty, so I accepted. So I have my lights back! I just need to get them fairly adjusted but the last time I had them adjusted the shop reported that the inside of one of my lights seems warped for whatever reason,a nd it won't quite go in place. I supposed the housing inside the shutter has come a little undone. ANy idea how to fix this instead?

If you can try and get me a pic of the part you are talking about..You can have mine i dont have my headlights in...See my cardomain in my sig and youll see why..If you can get back to me before the 10th ill get it too you as soon as possible..

Oh shoot, sorry I couldn't get back to you in time. I think I'll take the Supra down to the shop first and see if they can fix it this time, and then I'll get back to you though. Thank you so much for your help.

I brought all of my parts up from storage so let me what parts you need..