[FireJudge]

1969 GTO Judge. I keep blowing the tail lamp 20A fuse every time I turn on the parking lights. If I pull the headlight switch all the way out my headlights come on but NO tail lights or parking lights. I drove it 2 weeks ago and everything worked. I head to a cruise with the Indy GTO and the North east Indiana GTO club and I have this problem. I tried putting a 30A fuse in and I watched as it got hot and then it blew the 4A instrument panel fuse.
Any help? I assume it is a ground issue but where would I start?

[tigergto]

You can start by never putting a 30A fuse where a 20 is supposed to be. I would eliminate the headlight wiring. Possibly a short somewhere in the parking lights. Start there and look for a bare wire touching another bare wire or metal. Of course you may have caused another problem by using that 30A fuse.

[TedRamAirII]

Take a headlight bulb and wire it in where your fuse goes. now watch that light, glowing? if it is, then follow the harness moving wires and gently shaking the harness until it gets brighter or dimmer, so you can find the short. The brighter is gets the closer you are, and it will not let the smoke out of your wires. You want to mimic vibration like you are driving. Dont move it in big movements or you may temporarily fix it and not be able to find it.

[Squidward]

Based on your description, I'd guess that the headlight switch might be bad. I have what I think is a 69 schematic, but based on this and referencing my 72 guts that are all over my back patio, I think it should be close.

Disconnect the rear lamp harness plug, which should be very close to your fuse block. It's about 2.5 inches wide, 12 pin plug, and should be within 6-8 inches of the fuseblock. You should see a variety of wires in this connector, but specifically brown, light and dark green, white, tan, orange, and yellow.

This should half-split your front and back parking lights. See if your problem is still there. If it is gone, then move back to isolating the tail lights. On 70-72, the rear lamp harness is the junction point of parking light power coming from the headlight switch. It leaves power available to the front when the rear harness is disconnected.

If your problem never went away after disconnecting the rear lamp harness plug, then you can disconnect your forward lamp harness under the hood. Disconnect the battery first before pulling this apart because most of your power runs through the engine harness half of this. On the 72 the bulkhead connector unscrews as 1 piece, then the lamp harness plug slides out and separates from the engine harness. From what I see the 69 is the same configuration. Reconnect the engine harness bulkhead connector and see if your problem still exists. If it is gone, look in your forward lamp harness and bulb sockets for a wiring issue.

If it is still there, then it's pretty much the headlight switch, or some interconnecting wire mess inside your main harness/fuseblock.

Headlight switches are pretty easy to remove/replace. Push in a button on the rear body of the switch, and pull out the shaft. Unscrew the bezel retainer, and disconnect the electrical plug. If its an original, then it might be worth it to just pull the trigger and replace it. Unless you have hideaways, and then it's a bit more painful based on $$$.