I have a 1987 Toyota Pickup that I wanted to have brighter headlights in. I found a schematic for a wiring harness that did not look to complicated and went to work and wired up the power relays but had a hard time finding which wire powered the high beams until I found out that my system is a ground switching not power switching system.. I tried wiring the relay ground to the headlight ground but it was not enough of an open circuit and both high and low beams still come on. what can I do to make this work. I need my truck back. Thank you for your time.

 

Put it back to stock!!

Without knowing just what you have done it is impossible to tell you how to fix it.

Do you know what voltage you were getting at the light plug with your stock set up ??

 

My headlights worked but where very dim, stock harness uses wires that do not carry much current. I bought 30 amp relays from NAPA and wired the relay to the hot wire on the original harness the the relay return to the ground path for the headlight. I did the same for my high beam relay, only wired the return to the original high beam ground path. this results in when I turn on my lights, both high and low beams come on. I originally thought that my switch/relay in my steering wheel was bad, cleaned it all up and it tested it sat.

 

My experience with dim headlights is a blown fuse under the hood. I know there are replacement harnesses that can be bought that do the same thing you are wanting to do. I think it is ebay and 4crawler that sell them. Other then that I dont understand elelctrical to be able to help.

 

Excellent decision to correct the flawed stock wiring of the 4Runner/Pickup headlights.

All classic MoreFunners have switched ground headlight circuit.
IF you are not comfortable re-wring. Restore to stock, like Wyoming says, and just buy the conversion harness.

 

http://www.4crawler.com/4x4/CheapTri...shtml#TechInfo

These guys had some snags so read the whole thing.
https://www.yotatech.com/forums/f116...de-low-201388/

 

If it was in stock configuration I could tell the OP how to make it work.

If in fact they have the correct relays not all relays are created equal.

 

Of that I have no doubt wyoming. But you know some types...

They like to see where they're going