Hi volvoforums, welcome to my first post! So once upon a time about 5 months ago, I tried wring up a radio to my '91 740 with 271k(current) miles on it. One of the wires sparked to my relays, cause I'm an idiot and did not disconnect the battery first. I have no clue where or which wire it was. Since then, my headlight switch and brake lights don't work. The switch works in position 1, where it cuts on the running lights, tail lights, tag lights and instrument cluster lighting. Position 2 does not work, and registers as position 0, with everything cut off. My brake lights also do not work.

Since then, I have bypassed my headlights by running a wire straight to the high-beam wire to big blue wire running to the headlight switch. So now my high beams cut on when I turn the ignition over. My brake lights have been bypassed by drilling in and installing trailer lights to the plastic assemblies, with a wire ran to the high mount brake light that still works. I don't know why the high mount works and my lowers don't.

Can anyone tell me what I did or what I can do? I've given up on fixing the problem and have just bypassed everything. I've replaced the headlight switch and the Bulb failure sensor, both from junk cars, but was met with the same results. I've also replaced the headlight relay, To my understanding there is just one, but nothing changed.

Before I wired up the headlight bypass, I could pull the high beam switch and it would cut my headlights on until I let it go.

Good luck finding out this brain teaser, my guess is I blew a fusable link somewhere in the dashboard