Lighting Anomally
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Lighting Anomally
So I removed my fiberglass camper shell today (by myself, it was heavy). I noticed that one of the wires that were coming out from underneath my third brake light had somehow been severed. This wire normally does not exist but had been re-purposed from the middle light socket to connect to the wires that run through that top of the camper shell and to the third brake light at the back of the camper shell. After removing the lens and cleaning everything and reassembling, I noticed that the only way this light will come on is if I open a cab door or twist the headlight **** to turn-on the interior light. I assume that the previous owner had this done so as to connect an interior light inside of the camper shell.
How can I change this so that this light operates like it normally would (red on while headlights are on or brake is applied, white lights on the side on while in reverse)?
How can I change this so that this light operates like it normally would (red on while headlights are on or brake is applied, white lights on the side on while in reverse)?
Postmaster
Joined: Aug 2005
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From: Cleveland, TN
So I removed my fiberglass camper shell today (by myself, it was heavy). I noticed that one of the wires that were coming out from underneath my third brake light had somehow been severed. This wire normally does not exist but had been re-purposed from the middle light socket to connect to the wires that run through that top of the camper shell and to the third brake light at the back of the camper shell. After removing the lens and cleaning everything and reassembling, I noticed that the only way this light will come on is if I open a cab door or twist the headlight **** to turn-on the interior light. I assume that the previous owner had this done so as to connect an interior light inside of the camper shell.
How can I change this so that this light operates like it normally would (red on while headlights are on or brake is applied, white lights on the side on while in reverse)?
How can I change this so that this light operates like it normally would (red on while headlights are on or brake is applied, white lights on the side on while in reverse)?
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So that's the normal function? Why do I see the high mounted third brake lights of other trucks always on while they're just driving? Surely this truck can't be set up so that it only comes on when I open my my door, apply brakes and turn on the interior lights. It would make more sense, to me, if the white lights were to come on when the truck is in reverse and if the red light is always on when the headlights are on.
Is it really set up the other way!?
Is it really set up the other way!?
Tuned
Joined: Jan 2015
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White_97_xlt is correct. The red lens is a brake light, not a running light. It only has one filament (I'm thinking. I switched to LEDs a while back.). A running/brake light would have two filaments.
The white lenses are for illumination in the bed and connect to the interior dome light, they are not for reverse lighting.
The white lenses are for illumination in the bed and connect to the interior dome light, they are not for reverse lighting.
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White_97_xlt is correct. The red lens is a brake light, not a running light. It only has one filament (I'm thinking. I switched to LEDs a while back.). A running/brake light would have two filaments.
The white lenses are for illumination in the bed and connect to the interior dome light, they are not for reverse lighting.
The white lenses are for illumination in the bed and connect to the interior dome light, they are not for reverse lighting.
Lead Driver
Joined: Feb 2013
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From: Roseville, MN
I don't think you should use the Center High Mount Brake Lamp as a running light. If you do, yours will be about the only vehicle in the world to be like that which might tend to confuse people behind you. There might also be issues with legality.
If you are set on doing it, you will need to run another wire from a running light circuit to the brake light, and then you will need to install a dual filament socket and bulb (so it will go on brighter when you hit the brakes).
It also sounds like you have an actual problem. You say that your third brake light goes on with the cargo light rather than with the brakes. That sounds like someone crossed those wires. You need to find the brake light wire in there and get it (and only it) connected to the brake light socket.
As already noted, the white lenses are for a cargo light, not for backup lights. If you want to be unique you could run a wire for backup lights up there. But for me, a cargo light is way too useful to lose and the truck already has backup lights. So I'd stick with it the way it was originally.
If you are set on doing it, you will need to run another wire from a running light circuit to the brake light, and then you will need to install a dual filament socket and bulb (so it will go on brighter when you hit the brakes).
It also sounds like you have an actual problem. You say that your third brake light goes on with the cargo light rather than with the brakes. That sounds like someone crossed those wires. You need to find the brake light wire in there and get it (and only it) connected to the brake light socket.
As already noted, the white lenses are for a cargo light, not for backup lights. If you want to be unique you could run a wire for backup lights up there. But for me, a cargo light is way too useful to lose and the truck already has backup lights. So I'd stick with it the way it was originally.
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Tuned
Joined: Jan 2015
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I didn't change the wiring, only the bulbs.
I have seen newer vehicles that use this light as a running/brake light, but the older ones only use it for a brake light.
If you'd like it to be a running light AND a brake light you'll need a running/brake light socket and a two-filament bulb. Then you'll need to connect the running light side of the socket to a running light circuit. I think the wiring bundle to the rear lights runs inside the driver side of the frame. Identify the running light signal line and tap into it. You can then run a wire through the cab and up to the fixture. Or find a more suitable location to tap into.
I'll recommend not doing this, first, but if you must then use an LED bulb. Melting of the plastic by the standard bulbs is already a common problem with these fixtures and I'd be surprised if your's wasn't already melted. Most are, at least to some degree.
And you might as well change out the white lights for LED's also while you're in there so you never have to open it again.
I have seen newer vehicles that use this light as a running/brake light, but the older ones only use it for a brake light.
If you'd like it to be a running light AND a brake light you'll need a running/brake light socket and a two-filament bulb. Then you'll need to connect the running light side of the socket to a running light circuit. I think the wiring bundle to the rear lights runs inside the driver side of the frame. Identify the running light signal line and tap into it. You can then run a wire through the cab and up to the fixture. Or find a more suitable location to tap into.
I'll recommend not doing this, first, but if you must then use an LED bulb. Melting of the plastic by the standard bulbs is already a common problem with these fixtures and I'd be surprised if your's wasn't already melted. Most are, at least to some degree.
And you might as well change out the white lights for LED's also while you're in there so you never have to open it again.
Fleet Owner
Joined: May 2009
Posts: 21,437
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From: Gilbert, PA
It sounds as though you have a bad ground.
Also, LED bulbs in the taillights will also make the 3rd brake light come on like a running light too
Also. NO newer vehicles use a high mount running light. They are ONLY 3rd brake lights.
The ONLY vehicle that uses I high mount running lamp is the Raptor which has 3 red bulbs as running lights and when the brake is applied they get brighter.
They did this on Raptors only due to they overall vehicle width(86"). DOT states that vehicle over 80" wide need the ICC lights front and back. If you also notice on Raptors, they also have 3 amber lights in the grill for the same reason.
Again the same reason Dually all have cab lights and the 3 red lights typically under the tailgate
Also, LED bulbs in the taillights will also make the 3rd brake light come on like a running light too
Also. NO newer vehicles use a high mount running light. They are ONLY 3rd brake lights.
The ONLY vehicle that uses I high mount running lamp is the Raptor which has 3 red bulbs as running lights and when the brake is applied they get brighter.
They did this on Raptors only due to they overall vehicle width(86"). DOT states that vehicle over 80" wide need the ICC lights front and back. If you also notice on Raptors, they also have 3 amber lights in the grill for the same reason.
Again the same reason Dually all have cab lights and the 3 red lights typically under the tailgate
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