12v out for 3rd brake light on camper shell?

[Hickory]

I recently picked up a camper shell for my 22 PB and I have been having a hard time finding 12v for the third brake light hookup. I located the wire under the air box but unfortunately it is dead. I double checked on a co-worker's truck (23 5.0) and found that he had voltage on this wire when the brake was pressed so I know I am on the right wire. I have checked all fuses that seem relevant, and everything looks good. I have asked the dealer for help, but they have not been able (or willing) to figure it out.

The only thing I am wondering is if I could have disabled it somehow while messing with Forscan. I did most of the standard adjustments (dingers off, bambi mode, 75th anniversary splash screen). Could any of those have affected my 12v brake wire? Has anyone else had this issue and were you able to resolve it?

Thanks!

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[powerboatr]

Truck has to on or running to power that wire
And when you check it..use a voltmeter and get a good ground on the voltmeter lead or it will not power up
It has something to do with bms and saving power I believe

 

[Hickory]

Truck has to on or running to power that wire
And when you check it..use a voltmeter and get a good ground on the voltmeter lead or it will not power up
It has something to do with bms and saving power I believe

Thanks for your response. I am using a multimeter and grounding to the battery when checking. I checked the same way on my co-worker's truck and got a solid 13.5 volts instantly. I have checked with the truck running, with a trailer hooked up, and in accessory mode. Still no luck unfortunately.

Edit: I guess I haven't tried it with the ICE running, but I would assume that that is not necessary...

 

[powerboatr]

Not sure how just being on the hybrid elect mode affects it...
But on ice trucks..on or running energizes it with brake pedal depressed
Seems dumb a brake light is off if engine is off.
But.....you never know what they were thinking

 

[Hickory]

Yeah, I’ll test it with the engine running but don’t have much faith that’ll be any different. I’m really thinking it’s going to come down to a fuse, cut wire, or Forscan issue.

While researching I came across several threads discussing where to source third brake light power. In most threads there seemed to be a couple PB owners in there who had this same issue as me. I’m hoping maybe one of them figured it out and sees this thread!

 

[powerboatr]

Yep...ford for decades. Put a customer access wire at end of the bed, right near the trailer tow harness for use with toppers etc..guess moving it under hood was smarter ?????

 

[antho]

@Hickory What color is the wire that you have at the air box? @powerboatr Don't you have a topper? Did you wire your 3rd brake light?

 

[powerboatr]

@Hickory What color is the wire that you have at the air box? @powerboatr Don't you have a topper? Did you wire your 3rd brake light?

yes i got mine to work
its a funky color grey with an organgeish strip IIRC and its THIN as spaghetti

 

[Hickory]

@antho my wire is the same color and location as the one @powerboatr posted above.

 

[antho]

Thanks @powerboatr that the GY-OG Brake on/off circuit thats from the BCM. Interestingly enough they moved it for the 2024. I went to look at mine and its in the same location but different wire and it apparently comes from the BCMC. Thats why i was asking. Wasn't sure if the change was 2024 related but @Hickory confirmed its the same as yours while i was typing.

 

[powerboatr]

Thanks @powerboatr that the GY-OG Brake on/off circuit thats from the BCM. Interestingly enough they moved it for the 2024. I went to look at mine and its in the same location but different wire and it apparently comes from the BCMC. Thats why i was asking. Wasn't sure if the change was 2024 related but @Hickory confirmed its the same as yours while i was typing.

laugh

my dealer had no idea it was there and they cut into a rear brake light wire for others..
now they BE EDUCATED ? ?

 

[antho]

@Hickory Have you tried it with the truck running yet? Also, Do you have a trailer brake controller?

 

[Hickory]

@Hickory Have you tried it with the truck running yet? Also, Do you have a trailer brake controller?

Yep, tried it with the truck running, no luck. I have the factory brake controller.

 

[antho]

@Hickory When you get a chance can you see what value you have at the
BCMC 6F0-01-03
@powerboatr If you happen to be around or have the info, can you let me know what you have there too? Should just be 4 bits. Thanks!

I see some trucks with that value enabled and some not. That could be the issue.

 

[powerboatr]

@Hickory When you get a chance can you see what value you have at the
BCMC 6F0-01-03
@powerboatr If you happen to be around or have the info, can you let me know what you have there too? Should just be 4 bits. Thanks!

I see some trucks with that value enabled and some not. That could be the issue.

my asbuilt for 6f0-01-03
6F0-01-03 B001 AB no other characters
i am not sure if its been modified in that area, i have not in forscan

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