Tow bar harness electrical issue

[low ranger]

I fit a lot of the redarc units. I would recommend picking up the trigger wire (the red wire on the redarc unit) from the trailer plug itself & never from the brake light switch. That's red wire on the redarc controller to the red wire in the trailer plug harness.

[Cessa]

I did that first and when the unit didnt work and the voltage was low, i thought that i would get a better contact at the source so removed the wire at the plug and went to the light. This didnt work and hence the reason for this thread. The redarc unit is very straight forward and was starting to think it was the main reason for my issue. So i disconnected it and the fault is still there. Many hours of stuffing around.

[Billnick]

Originally Posted by Cessa

Would you know where the connection of the loom is located? I would think it is on the rear left panel but are there any indications of what it looks like?

Rear left panel on my XJ. Mine is just a long terminal strip.
11.7v, was this with the motor running? If the motor was off and your battery was showing 12.3, then 11.7 would be expected at the end of the skinny loom wiring. I've run a fat wire from the battery down to the rear panel to take care of this.

[cruiserfied]

Sounds like a short in caravan wiring to me.
I would assume the Mopar harness is plugged into the left taillight for brake signal which is why it doesn't operate with trailer plugged in.

[low ranger]

the voltage sent to the magnets by the brake controller will vary according to the situation you are in & it's highly unlikely that it would ever reach 12V. The tow-pro unit is more advanced that the cheaper RH model & will vary the voltage as required. the standard model (RH) is solid stage & set by the operator. Where in the rear loom have you connected the blue wire? Most factory looms have a the blue brake wire exposed at the end awaiting connection as required. The exposed end can short if you connect downstream from it without insulating the end.

[low ranger]

The factory towbar wiring loom is located LH rear corner & also uses an ECM. Completely plug & play. Have the dealer re-test his work, could be a faulty ECM or installation.

[bleetnblurt]

my wj has a little blue wire under the dash near the junction box , it does the so called electric brake , it is not used on mine mine runs a separate loom , which runs two wires to the back (blue and white ) low ranger is correct the connector is located behind the rear quarter inside panel , mine also had a extra earth wire running to the plug , so this tells me that the earth on it is not quite up to strength , by the way did you look at the web site I listed ?
and by some chance you didn't cross the wires back to front ? a diagram on these can look at little funny , mine runs the 12 pin flat plug , and the extra wires for the electric is on the 5 pins and NOT from the braking lights .