1981 240D electrical gremlins

[koooop]

Maybe this is a known issue, maybe not.

1981 240D, manual.

When I turn on the headlights the gas gauge sharply pegs to full, the temp gauge pegs out, both of the dash turn signals light up, the high beam indicator lights up. The turn signals do this as well snd when I put the car in reverse. None of this happens if I put on the left side marker right light the right side marker, turn on AC, blower or interior lights.

I had a bad headlight switch replaced a few years ago, it was doing bizarre things. I’m Almost thinking this may be related. To that switch.

Thanks