Trailer Tow Tail Light Circuit

[rspeers]

My 5th wheel tail light circuit shorted and opened the 20 amp Fuse 28. I replace it with a like fuse but the circuit is dead in the fuse block. Does the computer control these circuits when it senses a faule? I am having to do my travels during daylight hours which is slowing me down. Any thoughts will be appreciated.

2023 3500 Laramie 4x4 diesel

 

[Ozymandias]

Very likely the BCM controls these circuits like it did at the predecessor.
In your case I'd see the next dealer as your truck is under warranty, right?

 

[rspeers]

Yes it is. I have an appointment next friday. Thanks.

 

[Timd32]

Yes the computer controls the output of the 4 relays. LEFT, RIGHT, PARK, BACKUP each have a relay controlled by the BCM.

When the relay is called for it then closes and feeds the fuse power for the circuit.

That fuse 28 is the Backup relay from what I see, so it won't be hot at all times.

Here is the breakout.

LEFT = Fuse 53
RIGHT = Fuse 81
PARK = Fuse 29
BACKUP = Fuse 28

At times this system gets stuff wrong and there are all sorts of diagrams for each vehicle, just giving some more info to do some basic checks.

All are 20A fuses and the relays are identical as well.

Phone won't print this one, not the best screen shot at all....

 

[EzGlider]

Just had this issue with a bumper pull car trailer. Lost F29 for some reason. Tried to swap F28 and it would not work. Verified continuity on F28, also checked the fuse block for F29 and got power. I put a new fuse in to F29 once I could get one and it worked. Not sure why I could not get it to work when swapping.

 

[Timd32]

Just had this issue with a bumper pull car trailer. Lost F29 for some reason. Tried to swap F28 and it would not work. Verified continuity on F28, also checked the fuse block for F29 and got power. I put a new fuse in to F29 once I could get one and it worked. Not sure why I could not get it to work when swapping.

It sounds like a USB connector, try to plug it in upside down, does not work, flip over try right side up, does not work, flip over upside down works.....

Stuffs funny like that, I personally don't know these fuse types .

I don't see the relays listed in the one box.

I found the fuses, have not changed any of those ever.