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Old 02-18-2018, 02:38 PM   #7
VetteVet
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Join Date: Jan 2005
Location: Kalamazoo, Michigan
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Re: Lost dash, some, brake and side marker lights

Quote:
Originally Posted by Dwyert4 View Post
Ok,so the 20amp til stop/park dome fuse was blown. Changed it and it fried the second I turned the lights on. So bad switch? Do you have to pull the dash to change it? Just bear with me cause like I said this new to me. And thanks ahead of time.
What you are most likely to find is that you have a short to ground in one of the marker lights or the parking lights. Since the turn signals are working it tends to rule out the parking/turn lights,which leaves the marker lights or the wiring that goes to them. This includes the wiring that goes to the parking lights both front and rear.

Here is how the circuit is powered.
The fuse panel is powered by a hot red wire that is fused by the parking
lights, dome light, and stop light. On the other side of the fuse is an orange wire which carries power to the stop light switch, the dome light, and the headlight switch.

It appears that you are not blowing this fuse until you turn on the headlight switch. When you do that you send power from the orange wire to the brown wire on the switch that carries power to all of the tail, parking and marker lights.

Here is a picture of the fuse panel and in the lower right is the fuse panel with the red wire powering the fuse for the stop/tail lights and the orange wire from the other side of the fuse that goes to the dome light fuse, and the stop light switch, and the headlight switch.

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This is a picture of the headlight switch and the wires that go to it and what they power. You can see that the orange wire powers the brown wire that feeds the parking lights and markers.



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This one shows the orange wire going to the headlight switch in the lower right.

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The wires below it are the tail light and stop light wires going to the back of the truck.

You may have a wire shorted in that harness, or one of the lights powered by the brown wire, which will go to the tail lights, or the license plate light, or the rear markers if the 70 has those. The license plate light is a common place for a short to ground.

You can isolate the front lights from the rear lights by disconnection the harness on the engine side firewall just above and to the left of the distributor. This is the rear light harness and if you disconnect it and then turn on the headlight switch and don't blow a fuse, then the problem is in the rear of the truck or in the harness that runs along the frame.

If you still blow a fuse when you turn on the headlight switch then the short is in the cab or in the front of the truck. the wires that feed the front parking lights are purple and the markers are brown.
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