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High mount brake / cargo light not working

15K views 8 replies 5 participants last post by  slide9595 
#1 · (Edited)
Hi all. I'm new to this site. I have a 2008 f250sd. Which has the issues with the cargo light only not working. The. Brake lights work. I checked all fuses and relays and they are all good. Had to replace the light due to being burned out. Switch to an led light

I checked the voltage at the light. The brake light is getting 12 v. However the cargo is reading .002v. Pics below

I do have other issues that I am current working out. The front dome/map light is burned out and seems to work on one side only if the bulb is in the right position. Pic below both side are like this

I know the cargo light should turn on when the door is open. The key phob is used or the know next to the headlights switch is rotated fully up

Is the wiring to the cargo light tied to the dome/ map light?
 

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#2 ·
Ok. I followed the violet wire to the sjb. I tested it and got no power from the plug sjb out. I hooked a 10 amp fuse to a wire that ran from the batter n touched the wire and the cargo light came on. Pulled the plug off and tested it from the pin holes and the lights lite up. Tested the pins where the wire connects n has no power. Also the fist 4 in a square where the violet wire is don't have power either. This is in the sjb. So I'm thinking I need a new sjb
 
#3 ·
Don't have any of my info with me right now.

The SJB can disable an output if it goes into an over current event, Some times it can be reset and sometimes it can't. Some Code Readers will tell you if it is disabled. I believe it is a "U" code by my old memory.
 
#5 ·
#8 ·
High mount brake light wiring

I hate to bring it by your old thread but do any of you have the wiring schematic for the high mount brake light and possibly one that has the camera mounted in it? I’m trying to retrofit my 2015 super duty lariat to have the 17 high mount brake light with the camera
 
#9 · (Edited by Moderator)
It's not the brake light switch...if the regular brake lights come on when the peddle is pressed. The three lights are all fired off the same switch. Messing with that switch may cause problems for the guy that loans you his switch and for your switch. I was told that switch is a one time install. If you take it out it quits working. - this statement is unverified but may be true.
 
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