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Reverse lights.

Reverse lights.
J

jafo

Old Time Jeeper
Posts
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Location
Blue Springs, Missouri
Vehicle(s)
1979 CJ7. 304 V8 3 speed.
So I decided to replace the tail lamps today. Bought a set at the local autoparts store. Blazer brand. I only have one new one installed so far on ths drivers side. I had a couple wires backwards. Stock has one green and two white. The new light came with one black for the reverse light and a green and red for the running light and turn signal/brake light. Had a couple wires backwards. The green went to a white wire and red to the stock green wire and the black to the other white wire. My problem is I have the brake light and run light figured out. But I can't get my reverse light to work now. They worked before the light install, but not now. I wonder is I still have wires crossed.

What does it take for the reverse light to work? There is only three wires.
 
Have you checked that you have power going to the wire when in reverse? I usually have ground issues with mine. So I will suggest to make sure all is grounded well.

I recently replaced one with a newer aftermarket tail light. But cannot remember which wire went with which. I remember mixing them up the first couple of times. Let me go out and see if I can tell which connected to which.

Des this help?
17144f92717a032f7652c996a98bcd0f.jpg
 
Last edited:
Looks like mine without the mud, ha ha.

I am going to try to swap the red and green wires tomorrow and then check to see if I'm getting current when in reverse. It was just working earlier today. Only thing I did was wash the jeep and engine compartment then swapped this first tail light.

Where would the ground wire be for the reverse light? In back or by the tranny? I know these light assemblies have to be grounded properly to work. It came with those foam seals for the bolts. I put them between the light case and body. I didn't know where else to put them. Maybe that's not letting the light assembly properly ground.
 
These tail lights ground to the body. I think through the mounting bolts. I have a glass body so I run a dedicated ground from the inside of the light to the frame.
 
Anytime you start messing with wiring you need a good diagram. I use one from www.colorwirimgdiagrams.com On the '79 you have a small harness that runs inside the Jeep body to the back of the Jeep. Inside this harness there is 4 wires. A pink wire that goes to the float in the fuel tank, a white wire that goes to the tail lights and marker lights, a green wire that goes to the stop/turn signals on the right side, a white wire with a black strip that goes to the backup lights, and a green wire with a black stripe that goes to the stop/turn signal to the left side. The side marker lights may also have a blue wire to them instead of the white wire, but only for a short distance. All lights have a separate wire or a part of the housing that goes to ground and is black in most cases. Find where this harness comes out of the body and follow it back to the lights. A lot of times these get cut and somebody else has added different colored wires to this harness. Once in awhile you'll also find an orange wire. This could be for a hardtop. Some hardtops had a dome light in them. The orange wire was the 12 volts got to that. Good luck with you new lights. :chug:
 
Peanut Butter said:
Anytime you start messing with wiring you need a good diagram. I use one from www.colorwirimgdiagrams.com On the '79 you have a small harness that runs inside the Jeep body to the back of the Jeep. Inside this harness there is 4 wires. A pink wire that goes to the float in the fuel tank, a white wire that goes to the tail lights and marker lights, a green wire that goes to the stop/turn signals on the right side, a white wire with a black strip that goes to the backup lights, and a green wire with a black stripe that goes to the stop/turn signal to the left side. The side marker lights may also have a blue wire to them instead of the white wire, but only for a short distance. All lights have a separate wire or a part of the housing that goes to ground and is black in most cases. Find where this harness comes out of the body and follow it back to the lights. A lot of times these get cut and somebody else has added different colored wires to this harness. Once in awhile you'll also find an orange wire. This could be for a hardtop. Some hardtops had a dome light in them. The orange wire was the 12 volts got to that. Good luck with you new lights. :chug:
Click to expand...

Thanks for he info. Will check it out today.
 
Don't depend on the mounting screw to be a good GND.
LG
 
Well in general. I think the light is grounded fine because the brake light, turn signal and runing light works. I'd figure if it wasn't grounded none of it would work. But running q dedicated ground wire probably would be a good idea.
 
The factory ran a dedicated GND.
LG
 
jafo said:
Well in general. I think the light is grounded fine because the brake light, turn signal and runing light works. I'd figure if it wasn't grounded none of it would work. But running q dedicated ground wire probably would be a good idea.
Click to expand...



Looking into the light housing, does the reverse ground on the same metal piece as the tail/brake light? I will try to find a picture of the inside that I took. I am not sure if the both ground to the same metal part, but they may.
 
gr8dain said:
Looking into the light housing, does the reverse ground on the same metal piece as the tail/brake light? I will try to find a picture of the inside that I took. I am not sure if the both ground to the same metal part, but they may.
Click to expand...

I'll have to double check.
 
jafo said:
Is that the wires running through the back of the rear fender well? There is one on each side.
Click to expand...

The GND wire is on a ring terminal and mounted to the inside of the fender.
I recommend a dedicated GND wire for each TL housing.
LG
 
Ok. I went over the wiring in the back. Both new lights are un. Run lights, brake lights and flashers work great. Still no reverse lights. There is nothing wrong with this wiring. I made sure each light is grounded, still no reverse lights either side. So, it's some where else. It has to be back up under the dash area.

Let me ask a question on operation. Should the reverse light come on with or without the ignition on? In my mind they should only operate when the ignition is in the on position. I'm trying to eliminate myself as the problem operation wise. They currently will not work either with ignition on or off.
 
R-light should only come on with IGN in 'run' or accessory position.
LG
 
REMEMBER to always disco the battery POS(+) whenever dealing with the wiring.
LG
 
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