Installed new 7-Pin and now more problems

[Dg2408]

So after taking out the TT for the first time we found that the trailer was not being seen by the brake controller (Tekonsha P3) I have in my truck.

Long story short, both 7-pin connectors on my truck and the trailer were corroded and needed to be swapped out.

I cut the old trailer connector off and rewired the new one in the same sequence as the old one. On my truck I popped the old connector off and plugged in the new one.

The trailer is now seen by the brake controller and the running lights come on trailer but there are no turning indicators and the driver side tail light is illuminated like the brake pedal is being depressed while the passenger side is very dim. The lights do not change when I step on the brake pedal, turn the hazards on or the turning indicators.

Now I'm trying to understand how I went from one extreme to another lol

[Alan24601]

Voltmeter time.

[Bob_C]

Sounds like a bad ground....

[A32Deuce]

X2 on the ground.

[egwilly]

Sounds like you might have a couple wires connected incorrectly to the plug body's wire loom. Or a ground wire issue. But, the other lights work, so...........

Voltmeter is your friend at this point.

[JohnRR]

Agreed with a bad ground quick check for it is to run another external ground wire from the truck to the trailer almost any gauge wire will do as long as it has good connections then recheck your lights.

[Clomok]

Originally Posted by egwilly

Sounds like you might have a couple wires connected incorrectly to the plug body's wire loom. Or a ground wire issue. But, the other lights work, so...........

Voltmeter is your friend at this point.

Attachment 220156

Since everything “works” just on the wrong function, sounds like you hooked up the trailer connection to the wrong spots, especially if the trailer has had the umbilical replaced with a “utility” wire vs the “rv” wire color code, the pin out at the plug is the same, the color is just different

[Rickeoni]

Most of the replacement male connectors use screw terminals, perhaps a stray wire from the treaded loom is contacting a neighboring terminal.

[Dg2408]

Originally Posted by egwilly

Sounds like you might have a couple wires connected incorrectly to the plug body's wire loom. Or a ground wire issue. But, the other lights work, so...........

Voltmeter is your friend at this point.

Attachment 220156

Looking at your picture I can see my wires are setup different.


1. Blue
2. White
3. Black
4. Green
5. Brown
6. Red
7. Yellow

[Dav L]

I would use the wire color as an indicator to get started. I would use a multimeter and run the vehicle through it's paces to determine each wires FUNCTION. Then wire the function to the pins shown in the above graphic.
And wire the trailer for those same pins for the same function.
so, when you put on the right directional, you should see pin 6 pulsate zero to 12+ volts with each blink.

[Dg2408]

Originally Posted by Dav L

I would use the wire color as an indicator to get started. I would use a multimeter and run the vehicle through it's paces to determine each wires FUNCTION. Then wire the function to the pins shown in the above graphic.
And wire the trailer for those same pins for the same function.
so, when you put on the right directional, you should see pin 6 pulsate zero to 12+ volts with each blink.

Will definitely be looking for a you tube video on how to do that. This is all new for me.

[coupevilleDF]

Originally Posted by Dg2408

Looking at your picture I can see my wires are setup different.


1. Blue
2. White
3. Black
4. Green
5. Brown
6. Red
7. Yellow

When I converted from 4 pin to 7 pin connector, the colors were well documented on the purchased cable but they didn't match what I consider to be the industry standard for right, left, etc. With care, I was able to get all lights working, but it took a bit of planning not to screw if up.

[weredoingit]

Originally Posted by JohnRR

Agreed with a bad ground quick check for it is to run another eternal ground wire from the truck to the trailer almost any gauge wire will do as long as it has good connections then recheck your lights.

I use a set of Jumper Cables for this.

[JohnRR]

Originally Posted by weredoingit

I use a set of Jumper Cables for this.

I never heard of a eternal wire but I changed the spelling to external now