Ghost Voltage in Brake light circut

[RockRanger]

93 ranger no cruise.

I am working on swapping in some LED lights for my flat bed and am getting a ghost 7.8 volts to the rear brake light wires only when the ignition is on.

Key off brake lights work fine and no ghost voltage at the brake lights. Turn key on and the rear LED's will dimly light up.

Pulled the harness apart above drivers front tire and the voltage stays on the cab side of the plug. No voltage then in the wire running the length of the frame to the back.

Disconnect the brake switch at the pedal. Have 12V to the always hot side and 7.8V to the side that eventually goes to the the brake lights.

Pulled the harness apart at the large connector going into the cab. Have 7.8V on both sides of it.

Any ideas and does anyone have better wiring diagrams then whats in the back of a Haynes manual?

 

[adsm08]

Did you install the ground-side resistors for the LEDs? That happens because the LEDs don't have the resistance to block bleed-through voltage like incandescents do.

 

[Earl43P]

Yes, I have a lot of the 1993 EVTM schematics in .pdf format.

Send me a Private Message with your e-mail address and I'll send you what I've got.
It's not the whole book, but it is quite a few files.

 

[RockRanger]

Did you install the ground-side resistors for the LEDs? That happens because the LEDs don't have the resistance to block bleed-through voltage like incandescents do.

No I didn't. The voltage is only there when the ignition is turned on. The brake lights work with or without the ignition turned on. To me that means there is something tied to the brake light circuit only when it is hot. I am wondering if something is being fed through the rear wheel ABS system.

I did find that my trailer light harness was defective so I tossed it and am now running a separate amber light for the turn signals.

Yes, I have a lot of the 1993 EVTM schematics in .pdf format.

Send me a Private Message with your e-mail address and I'll send you what I've got.
It's not the whole book, but it is quite a few files.

PM Sent.