Oem high beams always on


New Member
Jun 4, 2023
New York
So I disconnected the headlights at the connector just outside the firewall. The high beam indicator and the fog lamp relay work fine. The low beam and high beam pins have power when they are supposed to. Seems like all is well up to this point.

However, when I plug them back in, it gets weird. With high beams on, everything seems to work but the lights are a bit dim. With low beams on, the lights are also dim, the high beam indicator stays on and the fog light relay still has power. I've checked all the individual wires and they seem fine. The ground wire is solid on both sides. Both lamps are new oem.

What seems to be happening is when using low beams, power travels down the VT/WT wire to the lamps, then crosses the filaments to the high beam side and travels back up the RD/OR wire thus powering the high beam indicator and the fog light relay. And this makes sense except that it is also wrong. The only thing that is not original is the H4 connectors but I don't think there is that much to them.

Maybe there is supposed to be a diode in there somewhere to prevent this. I can't find one and the service manual (8W-50-2,3) doesn't show one. I'm missing something but I can't figure out what it is.
Just a quick update. Seems the previous owner rewired the headlights and switched the ground and low beam wire inside the wire harness................