Dash lights
Cargo Master
Joined: Sep 2005
Posts: 2,954
Likes: 64
With the key on and lights off, unplug one of the dash lights and test that Blue/Red, is it hot?Eric
Fleet Mechanic
Joined: Sep 2016
Posts: 1,459
Likes: 70
From: Southern Maryland
It sounds like you have switched power going to the ground for the lights. When you turn the ignition on the lights are powered on with the reverse polarity of what is normal. When you turn on the head lights you then have 12 V on both sides, which makes the lights go out. There is supposed to be a ground wire on the back of the instrument panel that attaches to the frame, usually at the steering wheel support. Is that wire there and attached to the instrument cluster?
If there are no splices in the main under dash harness, you can't screw up the connections to the headlight switch. There is one hot at all times wire going to the switch and all the other wires are power coming out.
If there are no splices in the main under dash harness, you can't screw up the connections to the headlight switch. There is one hot at all times wire going to the switch and all the other wires are power coming out.
Cargo Master
Joined: Sep 2005
Posts: 2,954
Likes: 64
It sounds like you have switched power going to the ground for the lights. When you turn the ignition on the lights are powered on with the reverse polarity of what is normal. When you turn on the head lights you then have 12 V on both sides, which makes the lights go out. There is supposed to be a ground wire on the back of the instrument panel that attaches to the frame, usually at the steering wheel support. Is that wire there and attached to the instrument cluster?
If there are no splices in the main under dash harness, you can't screw up the connections to the headlight switch. There is one hot at all times wire going to the switch and all the other wires are power coming out.
If there are no splices in the main under dash harness, you can't screw up the connections to the headlight switch. There is one hot at all times wire going to the switch and all the other wires are power coming out.
ALex what are you using for a tester and how is it hooked up? If it's a test light, is it powered or non-powered.
Eric
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5th Wheeling
Joined: Jan 2020
Posts: 40
Likes: 0
Checking for 12 volts.
gonna double check the light wires again it’s been a while since I’ve been back there and now that I keep thinking about it I do recall something different about one of the light bulb wire but not sure
gonna double check the light wires again it’s been a while since I’ve been back there and now that I keep thinking about it I do recall something different about one of the light bulb wire but not sure
Thread Starter
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5th Wheeling
Joined: Jan 2020
Posts: 40
Likes: 0
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Cargo Master
Joined: Sep 2005
Posts: 2,954
Likes: 64
OK with the key off and the 2 amp fuse removed (should be a very short fuse). Turn on the park lights and make sure the rear tail lights are lit. If they are, check one of the fuse contact ends while turning the headlight switch, you should have voltage that starts very low or "0" and goes to 12V as you approach the interior light position. IF the terminal you're on doesn't do that, check the other one. If you don't have voltage at either of them, the light switch is definitely bad, but if that's the case, after you replace the switch there is going to be another issue. We will deal with that after. Let me know what happens.
Cargo Master
Joined: Sep 2005
Posts: 2,954
Likes: 64