High beams don't work, dim interior light
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Elder User
Joined: Apr 2005
Posts: 533
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From: Lindenwold, NJ
High beams don't work, dim interior light
One of my lights went dim. I installed a new light and they were working opposite. One was dim and one was normal. I messed with the harness and have both lights working the same but the low beam is extremely dim and the high beam is normal low beams. Sucks driving on dark roads. Also not sure if its related but the interior light is very dim.
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
You might consider not driving on dark roads without proper lighting.
Did this start at the same time? If you turn the dome light on with the headlight switch vs. opening the doors, does the brightness change?
Thread Starter
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Elder User
Joined: Apr 2005
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From: Lindenwold, NJ
You're saying that the replacement light functioned normally, but the previously-working light became dim with the new light in place?
I'm not sure exactly I just know they were messed up. It's been awhile.
What do you mean by "messed with the harness"? What changed? What specifically did you do?
It has new plugs on both lights and the colors never matched up so I tried switching the wires around.
You might consider not driving on dark roads without proper lighting.
S
Low beams still work. This is my daily driver at the moment:
Did this start at the same time? If you turn the dome light on with the headlight switch vs. opening the doors, does the brightness change?
This I'm not sure of but it did work fine before. The lights on or off does not affect the dome light
I'm not sure exactly I just know they were messed up. It's been awhile.
What do you mean by "messed with the harness"? What changed? What specifically did you do?
It has new plugs on both lights and the colors never matched up so I tried switching the wires around.
You might consider not driving on dark roads without proper lighting.
S
Low beams still work. This is my daily driver at the moment:
Did this start at the same time? If you turn the dome light on with the headlight switch vs. opening the doors, does the brightness change?
This I'm not sure of but it did work fine before. The lights on or off does not affect the dome light
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
That's not what I'm asking. There are two ways to actuate the dome light: turning it on by opening the doors, or turning it on by rotating the headlight switch **** all the way counter-clockwise until it clicks. Is there any difference in brightness levels between the two methods of turning on the dome light?
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Elder User
Joined: Apr 2005
Posts: 533
Likes: 2
From: Lindenwold, NJ
If you've moved wires around beyond the factory configuration, then I have no baseline from which to help you. You need to restore the truck's wiring to the factory configuration. I can help you find a factory wiring diagram and explain the colors to you if that would help.
The only wires I changed around were when I installed new light bulb sockets onto the existing headlight harness on both sides. The colors didn't match so I just hooked it up so they worked. If you can give me a diagram of what wire goes to what prong that would be perfect. It's a 79
That's not what I'm asking. There are two ways to actuate the dome light: turning it on by opening the doors, or turning it on by rotating the headlight switch **** all the way counter-clockwise until it clicks. Is there any difference in brightness levels between the two methods of turning on the dome light?
No difference between the switch or the door actuator
The only wires I changed around were when I installed new light bulb sockets onto the existing headlight harness on both sides. The colors didn't match so I just hooked it up so they worked. If you can give me a diagram of what wire goes to what prong that would be perfect. It's a 79
That's not what I'm asking. There are two ways to actuate the dome light: turning it on by opening the doors, or turning it on by rotating the headlight switch **** all the way counter-clockwise until it clicks. Is there any difference in brightness levels between the two methods of turning on the dome light?
No difference between the switch or the door actuator
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
The entire circuit is shown in the top left. The box on the lower right shows the position of the prongs.
I'd start by pulling off the dome light cover and seeing what voltage you have across the bulb. Then see what the voltage is with the bulb removed, to get an idea of how much is dropping when the circuit is pulling current.
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Elder User
Joined: Apr 2005
Posts: 533
Likes: 2
From: Lindenwold, NJ
Ok I hooked up the headlight harness as the diagram you posted said and they are doing the same thing. The low beams are very dim probably half as bright as they should be and the high beams are from what I can tell normal low beams. They were hooked up wrong so I hoped this fixed the problem but no change.
I took the cover off the interior dome light and just touched it and it brightened up how it should. Maybe it had a bad connection. So that is good.
I took the cover off the interior dome light and just touched it and it brightened up how it should. Maybe it had a bad connection. So that is good.
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Post Fiend
Joined: Apr 2008
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From: Big Sky Country
This is one of those good "bang for your bucks" upgrades...
It's only 30+ bucks, stupid easy to install, and you'll get 30-35% better light output.
Heavy Duty Headlight Harness
It's only 30+ bucks, stupid easy to install, and you'll get 30-35% better light output.
Heavy Duty Headlight Harness
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MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
It's reasonable to believe that you're seeing poor light output because you're dropping too much voltage across the connections out to the bulbs themselves. Possibilities include a failing headlight switch, faulty splices out to your replacement connectors, or gummed up connectors themselves.
If you can get at the terminal to measure the voltage with the terminal still in place, I'd repeat the voltage drop measurement I recommended for your dome light (check the voltage loaded and unloaded) to get a better idea of what's going on.
If you can get at the terminal to measure the voltage with the terminal still in place, I'd repeat the voltage drop measurement I recommended for your dome light (check the voltage loaded and unloaded) to get a better idea of what's going on.
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