headlight power all the time? no high beams

[heavymetal]

hey guys, I bought the truck a year ago and I've slowly been working away at the issues it has. I live across the street from work so it hasn't been a big deal yet,but now I have to drive by a cop shop every day and I need my headlights working correctly.

So, in the truck, I turn on the headlights and low beams work. turn on the highs and no indicator on dash and no high beams. tried different bulbs, same thing. Pulled headlights, removed 9004 bulbs and tested plug. Has power on all three with high beams, power on 2 outside terminals on low beams. Has power on all 3 when truck is off??? headlight switch and harness appear to be fine. turn signal switch and wiring appear to be fine.

Why do they have power when the truck is off? is it possible the P.O put the wrong switch in, if he replaced a switch?

 

[ouch1011]

The headlight ground is what is switched on these trucks. The power is constant from the fuse, regardless of key or switch position. If low beams work and high beams don't, odds are the dimmer portion of the turn signal switch is bad.

 

[heavymetal]

I did try another signal switch I have from a previous truck I thought worked, but it is used so...

I spent another yesterday chasing wires, checking connections, ect. Everything looks fine. I fixed a few of these 2nd gens where the issues were right in the back of the turn signal switch plug but not that lucky on this.

I'll try a switch, thanks for the reply.