Scott's 1967 GMC 1500 pickup

[silver_bullet]

Agreed, I have been watching this on other forums as well, and seem to feel that the unit is of sound construction, the supporting fuel control center seems to be where most of the complaints lie....

[TheSilverBuick]

All I ask is, if it does give you problems, is to see if you can modify the vent and possibly make a change to your vent return to see if it cures it

[Scott Liggett]

I am trying to find a short somewhere in the electrical system. I keep blowing the brake light fuse when I turn on the parking lights, which includes the dash and taillights. All of these go out when the brake fuse blows. I am beginning to think some wire between the light switch and fuse block has melted into another. I just have to find it. It is also not instant. Sometimes it will last for days, sometimes it is instant as soon you you hit the light switch.

[squirrel]

Also check the wiring at the rear of the truck, it's usually a kluge from folks wiring in trailer lights.

[Scott Liggett]

I had to fix the trailer hitch lights wiring when I bought the truck. I checked out my work, didn't see anything that went wrong since then. I will disconnect the rear harness at the firewall plug and check things out. Fiddling with the wiring coming out of the bottom of the fuse block for the dome light has the dash lights going on and off.

[Scott Liggett]

Jim wins the Cupie Doll. It was the tail light harness. Thankfully, not my work was not the problem. The old wiring had cracked and got into another wire. The test when I drive to work tomorrow, bouncing over railroad tracks and dirt roads.

[Scott Liggett]

Looks like I spoke too soon. Got halfway to work and fuse blew again. I will try to find a place I can drive with the tail light harness unplugged and not get into a wreck or deal with cops.

[Beagle]

Chasing that stuff can get frustrating. Maybe a 10 buck Harbor Freight trailer light kit, splice it in up by the cab for a temporary test. They have magnetic ones too for a few bucks more.

[Scott Liggett]

I tried something last night while out running errands. I unplugged the tail light harness and drove with lights on and the fuse blew. I drove home with no taillights at all, but it is all on the busiest business street in town. Plenty of lighting. So, that harness is not the problem. Here is the weird thing, I plugged the harness back in so I would have hazard and turn signals. I live on a dark street and moved the truck from the front driveway to my garage with hazard lights on. When I hit the brakes, the dash lights that were out, started flashing with the flashers. How the dash lights are getting power from the flashers and brake lights is the clue. I believe the problem is under the dash. Probably wires for brakes and dash lights melted together somewhere. Fun stuff.

[SuperBuickGuy]

grounding through a bulb is my guess....

[Deaf Bob]

Grounding thru the pedal?

[JOES66FURY]

grounding through a bulb is my guess....

My guess as well.

[Huskinhano]

Don't rule out the turn signal switch. Usually the brake light circuit goes through that.

[Scott Liggett]

Don't rule out the turn signal switch. Usually the brake light circuit goes through that.

But, the dash lights do not. The problem is the brakes and dash lights wiring shorting out between themselves.

[Huskinhano]

Jim sidetracked me, that's my excuse.