My 97 Pontiac transport has an electrical problem. How can I self diagnose?

Question

Horn blows fuses, passenger door window & sliding door inoperable, interior lights stay on. Help!

Answer 1

You have a loose or broken ground. Very hard to find yourself. Try and if you can't, take it to an auto electric mechanic.

Answer 2

a poor ground isn't going to make a light stay on.
it isn't going to cause fuses to blow.
it may cause something to not operate at all or be intermittent.

sounds like multiple issues here.

when u blow the horn, the button grounds a the horn relay which grounds the horn. Some cars switch the + lead instead of the ground. Find the horn (may be 2 units), disconnect a wire and try again. if it doesn't blow the fuse either a horn is bad or there is a short to ground past the wire u disconnected.

If it does blow fuse check the horn relay.

the windows mayhave a blown fuse.
the sliding doors may have fuses blown. they may have lost sync, but u usually can still open with internal switch.
or there may be an open wire or bad ground. There may also be a controller problem. My Honda has controllers for everything and they "talk" on a single wire system.

the interior lights have a switch that controls ON, OFF, DOOR.
if the lights are always on make sure it is in the DOOR position. Otherwise look for a defective OFF switch, a defective door switch, or a short to ground on a door switch wiring.