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Im going to start this with saying I lack understanding in the world of 12v electronics.
My issue is, i have NO trailer power to my 7 way plug on the back bumper, i have tried testing with a multimeter and a trailer plug tester. I dont know where the ground for the plug is or which fuses to check, can anyone help me out? Thanks.
check your manual for fuse location.& relays...(going from memory here so bear with me it's old & also late)......
You should & need relays installed in the engine fuse panel for the signals & probably other things to work in that 7 wire plug !!
Those trucks if purchased with a tow package came with those items including a small wiring harness (for wiring the brake controller)
came in a plastic bag that was put in the glove box!! It was not uncommon for owners to leave them in the package & never install them !!
(dealers also did not in many cases here in canada install them in their pre delivery)
Do you have a Oem dash installed brake controller....If not what I said above is VERY probable for the relays etc. !!!
Other than that harness there was a relay for L & R signals for sure !! can't remember what else was in that bag but it all had to do with that plug working..
A big thing with the wiring harness @ the 7 wire plug was the ground... It goes back to the frame & probably by now is very corroded @ the frame connection !!
It is usually a black wire & may have or be tied into the grounds for the tail & license plate grounds....all black wires !! check & clean it !!
Good Luck !!
check your manual for fuse location.& relays...(going from memory here so bear with me it's old & also late)......
You should & need relays installed in the engine fuse panel for the signals & probably other things to work in that 7 wire plug !!
Those trucks if purchased with a tow package came with those items including a small wiring harness (for wiring the brake controller)
came in a plastic bag that was put in the glove box!! It was not uncommon for owners to leave them in the package & never install them !!
(dealers also did not in many cases here in canada install them in their pre delivery)
Do you have a Oem dash installed brake controller....If not what I said above is VERY probable for the relays etc. !!!
Other than that harness there was a relay for L & R signals for sure !! can't remember what else was in that bag but it all had to do with that plug working..
A big thing with the wiring harness @ the 7 wire plug was the ground... It goes back to the frame & probably by now is very corroded @ the frame connection !!
It is usually a black wire & may have or be tied into the grounds for the tail & license plate grounds....all black wires !! check & clean it !!
Good Luck !!
I appreciate this response and will look at it all tomorrow when i have light. That was very informative, thanks. By any chance do you know which fuses? When i bought the truck, the glovebox was empty, with no manual.
The two relays in the bag mentioned were for the trailer brake controller and I believe reverse lights (or was it battery charge?) for the trailer itself. Nothing really relevant to the issue at hand.
Not it too long back, we had a similar issue with our company truck. Lights work on another truck, but not our company truck (‘04 Heritage). Reach up into that driver’s side frame rail and clean that ground screw off really nice. Ours was caked in all sorts of dirt, but wiping it down did the job. Might need to drop the spare tire, but it is reachable.
The ground in this example is that white wire beneath the black plug.
Last edited by Johnny Paycheck; Apr 23, 2020 at 10:07 AM.
I appreciate this response and will look at it all tomorrow when i have light. That was very informative, thanks. By any chance do you know which fuses? When i bought the truck, the glovebox was empty, with no manual.
It seems I may have been wrong that there is a separate fuse/relay in that engine fuse box (later years had it)
Download that maual & go into the fuse identification pages ....Chk all fuses !!... then check your plugs again...if no power see below.... (still going from memory so maybe a little off on locations)
If you go under the rear of truck up in the drivers side frame...probably a foot or so ahead of the rear bumper there should be a major harness connection...You can split that & check for power there
Like I said chk the ground wires that goes from the plug /tail/lic. plate etc!!
Trailer Plug/Lights question
