HMMWV Reverse lights

[TurboR1]

I didn't like the round factory style reverse light on the bumper and most lights looked cheesy so I used the blackout light location for driver familiarity and to maintain the military look. While searching I didn't see anyone else with this setup so I figured I'd share. I also added a fog light below like some of the guys I saw on here.

The blackout light has a bulb socket that is the same as the turn signals. Then the the blackout cover lens needs to removed the the main tail light lens cover.

 

[thoner7]

Thisnis a great idea. How exactly would you do it?

 

[mgFray]

First you need to add the reverse switch and get power to it. Lot of the time people will buy a kit (with bracket and switch for the 4L80 or just hte switch for the 3-speed). You split power up at the horn, run it back to the switch, then back to the lights (I went along the main wire harness to the bad with my stuff).

Then I assume for this mod they modified the blackout light lense, and just removed the blackout light power and replaced it with the power from the backup switch.

(You go from the horn because the power is switched the same as it is for the rest of the lighting...)

 

[Myrddin]

First you need to add the reverse switch and get power to it. Lot of the time people will buy a kit (with bracket and switch for the 4L80 or just hte switch for the 3-speed). You split power up at the horn, run it back to the switch, then back to the lights (I went along the main wire harness to the bad with my stuff).

Then I assume for this mod they modified the blackout light lense, and just removed the blackout light power and replaced it with the power from the backup switch. A diagram would be great.

(You go from the horn because the power is switched the same as it is for the rest of the lighting...)

I’m digging this back up from the grave

Question. I am trying to plan this reverse light project now. I bought a fresh 4 speed shifter, and the Black Dog reverse wire harness. I have the LED tail lights with the reverse light built in (installed now). Waiting on the other parts.

The question I have is that I think I need more parts. I need to power the reverse light in both tail lights. Also if I follow the Black Dog install, I think reverse lights will only work in service drive (with head lights and so on). I want the reverse light to work with both day time and night time modes. Not sure I can do that. If I use the horn as a power source, what do I need to hook it up in conjunction with what I have. And how will it work exactly. Only when I switch on the day or night mode?

Any help would be great. I’m just not sure how it will work. And I don’t like the thought of only in night time mode.

 

[mgFray]

The horn power is used because the Horn will run in all “regular driving positions” but not in Blackout (BO) mode in the light selector. So if you want reverse lights even in blackout (or if lights are off) you’ll need to find power from somewhere else. The horn is easy, just find the 24V side, use a Y and run it to the switch. Out of the switch to your new lights whatever they are and ground the lights to the existing lighting grounds in the back.

 

[Mogman]

The horn power is used because the Horn will run in all “regular driving positions” but not in Blackout (BO) mode in the light selector. So if you want reverse lights even in blackout (or if lights are off) you’ll need to find power from somewhere else. The horn is easy, just find the 24V side, use a Y and run it to the switch. Out of the switch to your new lights whatever they are and ground the lights to the existing lighting grounds in the back.

The horn is circuit #26A it is connected to terminal J on the light switch and is not powered except in stop/service drive.

Unless some are different, I just tested the R1 in my shop and the horn does not work with the light switch off.

 

[mgFray]

On mine the horn is on in both modes flipped to the right:

it is NOT on in the BO modes to the left, only to the right.

 

[Myrddin]

The horn power is used because the Horn will run in all “regular driving positions” but not in Blackout (BO) mode in the light selector. So if you want reverse lights even in blackout (or if lights are off) you’ll need to find power from somewhere else. The horn is easy, just find the 24V side, use a Y and run it to the switch. Out of the switch to your new lights whatever they are and ground the lights to the existing lighting grounds in the back.

Do you know if it’s a 14 gauge wire. I just ordered some with 14 gauge male and female connectors as well as the y connector. The black dog harness has two wires at the switch end. If I split the horn to the switch how do I connect the other wire in the black dog harness? Or do I cap it off and just use one lead (sounds right). I think I have the tail lights sorted out too. I just split it agn off the lead I run back (single lead in the black dog harness in this case) and run a wire to each light in the led housing (wire marked R). Does this sound right? If so can you point me to the horn wire? I’ll be going out to the garage later this week to look it over.

 

[Mogman]

On mine the horn is on in both modes flipped to the right: View attachment 928673

it is NOT on in the BO modes to the left, only to the right.

Yes stop/service drive, not hot all the time.

 

[Myrddin]

I’ll go chk this week. How about the location of the packard connection to plug the y into. Without looking, I’m guessing it’s on the steering column or close? I’m sure it will stand out once I put my hands on it. I’m good not having all lights in BO mode. I just care about service drive and stop light.

 

[Mogman]

I’ll go chk this week. How about the location of the packard connection to plug the y into. Without looking, I’m guessing it’s on the steering column or close? I’m sure it will stand out once I put my hands on it. I’m good not having all lights in BO mode. I just care about service drive and stop light.

The wire going to the steering column is the wrong side of the circuit, the horn button grounds the horn completing the circuit.
If you look at the schematic above you are looking for wire tag 467 coming out of the light switch, that powers the turn signals and horn.
Do not forget to fuse the lead you add.

 

[Myrddin]

The wire going to the steering column is the wrong side of the circuit, the horn button grounds the horn completing the circuit.
If you look at the schematic above you are looking for wire tag 467 coming out of the light switch, that powers the turn signals and horn.
Do not forget to fuse the lead you add.

Thanks! That gives me a starting point.

 

[mgFray]

You want power from the horn under the vehicle. Two wires in, one is power and one is ground (switched at the steering wheel as mentioned above)

as for wire gauge, I think the lighting is 14 gauge, while grounds are 12 gauge. But this is completely from memory. I thought I had found the wiring gauge listed in the wiring diagram at the end of the 3rd technical manual, but I just don’t remember.

 

[Myrddin]

You want power from the horn under the vehicle. Two wires in, one is power and one is ground (switched at the steering wheel as mentioned above)

as for wire gauge, I think the lighting is 14 gauge, while grounds are 12 gauge. But this is completely from memory. I thought I had found the wiring gauge listed in the wiring diagram at the end of the 3rd technical manual, but I just don’t remember.

Is it the same wire that goes to the horn? Can’t I just start there and work my way back? I wish I could go look. But I guess once I am able I’ll see where the wire is.

 

[Mogman]

Is it the same wire that goes to the horn? Can’t I just start there and work my way back? I wish I could go look. But I guess once I am able I’ll see where the wire is.

Have you downloaded the TMs including the maint TM with the schematics?
You are looking for wire tag #26 at the horn, #25 goes to the horn switch in the steering wheel.

 

[Mogman]

Is it the same wire that goes to the horn? Can’t I just start there and work my way back? I wish I could go look. But I guess once I am able I’ll see where the wire is.

That wire like just about every wire goes into a harness so you cannot "follow" it.

 

[Myrddin]

Have you downloaded the TMs including the maint TM with the schematics?
You are looking for wire tag #26 at the horn, #25 goes to the horn switch in the steering wheel.

Yeah I have them. I’m just not around the garage. Just trying to get as much info as I can. I’ll see what I can find once I have my hands on it. I’ll be able to look tomorrow I think. Sounds like I may find it under the dash? I’m just unsure where to start. You know how it is when you have half a puzzle. I just don’t have the Humvee with me at the moment. I’ll dig around under the dash for a plug end with a 26 tag on it. I’ll share what I find and the location as well. I’ll also look under the body as well. It would be easier to run if it’s near the shifter.

Edit. The other thing I’m dealing with. When they did the Raptor Liner, they sprayed the wires under the dash. So a lot of the number tags are covered up. I have been blessed big and replacing items as I can. But it’s a bit hard for me to get under the dash. I have had some success scraping the tag and being able to read the numbers. But when they are all grouped up, it’s tough.

More to follow.

 

[Myrddin]

Have you downloaded the TMs including the maint TM with the schematics?
You are looking for wire tag #26 at the horn, #25 goes to the horn switch in the steering wheel.

I couldn’t stand it. So I drove home to look for a few min. I see the horn, however the past owner has installed a new horn, it’s mounted just forward the location of the original (that’s still mounted in its factory spot). To install the new horn, they cut the ends off. And used the typical female electrical connectors. Sounds like your stating I need to I’d the hot wire (I have a meter), and put the Packard connector on, run the wire to the Y connector, then re connect the current horn wire, and run a new wire to the reverse switch, then use the black dog harness to run the wire back to the reverse lights, where I’ll prob use another Y connector to get to each tail light (that has the reverse light inside).

Sound right? I almost wish I didn’t order the harness. But it includes the switch and adapters to make it work. So I guess it’s fine.

Is it normal to bypass the horn?

 

[mgFray]

Normal? Not really, but not unusual.

But yes, Y the power wire and you should be good

 

[Milcommoguy]

I couldn’t stand it. So I drove home to look for a few min. I see the horn, however the past owner has installed a new horn, it’s mounted just forward the location of the original (that’s still mounted in its factory spot). To install the new horn, they cut the ends off. And used the typical female electrical connectors. Sounds like your stating I need to I’d the hot wire (I have a meter), and put the Packard connector on, run the wire to the Y connector, then re connect the current horn wire, and run a new wire to the reverse switch, then use the black dog harness to run the wire back to the reverse lights, where I’ll prob use another Y connector to get to each tail light (that has the reverse light inside).

Sound right? I almost wish I didn’t order the harness. But it includes the switch and adapters to make it work. So I guess it’s fine.

Is it normal to bypass the horn?

Only if one wants to go from a beep beep road runner to honka honka louder horn.

Motorist... Can you hear me now, CAMO