Reverse Light Wire

[Sauce]

I want to add aux reverse lights with a relay triggered by the oem reverse light signal. It doesn’t appear that feature is specifically fused (tell me if I’m wrong) so since I can’t fusetap the relay im planning to tap the wire directly. Does anyone know the wire color for the reverse light? I should have gotten it when I paid for 24 hour access to the service manuals but I didn’t ?

Also, anyone know if there’s enough fuse capacity to tap a couple amps power from that wire or would I be better off just wiring to the relay and using aux power?

assuming I only need to tap one side.

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[Sauce]

Anyone have the details?

 

[ntbruncie]

If you look down by the hitch on the outer side of it you will see a harness you can tap in there. The harness leading up to the tail lights it’s not going to help you, all the wires are black.

 

[Sauce]

Thanks a lot. Looks like I’ll tap the green / brown wire there.

any idea if it’s fused with enough headroom to tap another 2 amps, or should I just play it safe and tap it to a relay and run power separately?

 

[ntbruncie]

The harness comes straight from the BCM. I would run a relay and power.

 

[ShadowDragon24]

Diode Dynamics C1R pods. using the 2 output 7pin trailer harness I did have to modify the harness. the new universal one they came out with a few years that you could tie one wire into the brake to stop the trailer light error wouldnt work. when ever my I would turn on a turn signal I get that side trailer bulb error because the c1r wasnt flashing, except when my foot was on the brake. the error go away.

so I was getting a cap, and as per the ford body builder guide, I tapped the 3rd brake wire at the bcm, and ran wire to back, tried the brake wire in the plug the provided, still didnt work.

I know these 3rd brake modules for trailers take signal from both turn/brake on a trailer. so I cut the other side brake/turn signal, and attached both wires to the brake wire I ran.

Now the trailer plug powers the marker lights, and the reverse, and the bcm 3rd brake circuit powers the led in the 3rd brake I added. the c1r's, and the cap.

If you however put too much current on the 3rd brake circuit for a cap, etc, you'll need to disable the 3rd brake on the truck. or add in a relay

 

[pezdyspensr]

Diode Dynamics C1R pods. using the 2 output 7pin trailer harness I did have to modify the harness. the new universal one they came out with a few years that you could tie one wire into the brake to stop the trailer light error wouldnt work. when ever my I would turn on a turn signal I get that side trailer bulb error because the c1r wasnt flashing, except when my foot was on the brake. the error go away.

so I was getting a cap, and as per the ford body builder guide, I tapped the 3rd brake wire at the bcm, and ran wire to back, tried the brake wire in the plug the provided, still didnt work.

I know these 3rd brake modules for trailers take signal from both turn/brake on a trailer. so I cut the other side brake/turn signal, and attached both wires to the brake wire I ran.

Now the trailer plug powers the marker lights, and the reverse, and the bcm 3rd brake circuit powers the led in the 3rd brake I added. the c1r's, and the cap.

If you however put too much current on the 3rd brake circuit for a cap, etc, you'll need to disable the 3rd brake on the truck. or add in a relay

Pardon me reviving this old thread, but you say you tapped the CHMSL at the BCM.. According to the builders guide, that circuit is already closed in Connector 5. There's also very little additional amperage capacity according to that chart that you could pull before, I assume, getting an error. Did you simply cut and/or splice into the available yellow/gray wire under the dash or is there another way?

 

[ShadowDragon24]

Pardon me reviving this old thread, but you say you tapped the CHMSL at the BCM.. According to the builders guide, that circuit is already closed in Connector 5. There's also very little additional amperage capacity according to that chart that you could pull before, I assume, getting an error. Did you simply cut and/or splice into the available yellow/gray wire under the dash or is there another way?

I added a very low draw led bulb to my 3rd brake light. this puts it on par with the lariat/raptor amperage available. maybe even higher. I spliced into the yellow wire with grey stripe in pin 13 locstion in connector 5, that feeds the 14g wire I got from the engine bay to the rear. that then splits off to the 3rd brake for the cap, and then to the c1r harness module to power the brake function of the c1r's.

If you're adding extra, or going above the 1.55a of the circuit(if you remove the chmsl brake function) you can always add in a relay off the battery, and use the pin 13 connector 5 wire to trigger the relay. like how ford says to do if you use any of the blunt cut keyed ignition, high beam, or marker light trigger wires under the trm/bcm behind the drivers kick panel.

I got the ignition spliced into my diode dynamics dswitch to automatically turn it on and off. the marker light wire on the night mode wire to turn on my backlighting busbar, and turn on the backlighting of the button panel, my dd elite series fog backlighting, and my grill lights. The high beam wire on one of the dswitch's programable trigger wires, that automatically turn on my lower grill cubes, and on longer drives, Ill add in my ss40 bar. but normally I keep that sepperate from the grill/highbeams.

 

[pezdyspensr]

@ShadowDragon24 thanks for the detailed explanation. I've learned a lot on this forum because of folks like you! You say you spliced at the connector. Does that mean you cut the wire and did a 3 way butt connector, or did you do an inline military splice, or are you talking about depinning and repinning the connector?

I love your setup. Noticed you are in Newfoundland. For cutting through some decent fog, I imagine. I'm on the Maine coast and can relate.

My motivation is less glamorous. I have a rare 24 STX with no tow package and no way to tap existing wiring, so I am going the route of the 5G Rangers and tapping off the CHMSL wire to trigger a Red Arc Liberty I purchased (along with their encapsulated diode to avoid backfeed voltage). Also running it off an ignition switched relay so I can avoid being always hot. Just deciding whether to actually cut the CHMSL wire at the BCM or do something more elegant - particularly since I still plan to get a cap with 3rd brake at some point.

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