Tow wiring not working

[spineb]

I have a ‘22 GCL Overland with the trailer-tow package from the factory.

I am not receiving any signal from the tow wiring, except for constant 12v power on the positive (+) pin located on the 7-pin connector. None of the other pins are getting any signal, nor are any of the pins on the 4-pin connector.

I could have sworn that everything worked fine last summer and I haven’t made any modifications since. I checked the 5 fuses that the owner’s manual mention “towing,” and all are fine.

The only thing left I can think of is that the wiring signals are turned off in the ECU, though I’m not sure how that would affect the constant power that is still working.

Does anyone know of anything else to check before going to the dealer?

 

[MotownBob]

My experince with tow wiring is that it is directly connected to the taillight wiring [brake lights , turn signal, etc] so there would be no reason to involve the ECU. Perhaps a wiring issue back there somewhere, loose connection etc...

This Video explains all the wiring :

https://www.etrailer.com/tv-install-tekonsha-4-pole-trailer-wiring-2023-jeep-grand-cherokee-l-tk39vr.aspx

 

[Juggernaut]

I have a ‘22 GCL Overland with the trailer-tow package from the factory.

I am not receiving any signal from the tow wiring, except for constant 12v power on the positive (+) pin located on the 7-pin connector. None of the other pins are getting any signal, nor are any of the pins on the 4-pin connector.

I could have sworn that everything worked fine last summer and I haven’t made any modifications since. I checked the 5 fuses that the owner’s manual mention “towing,” and all are fine.

The only thing left I can think of is that the wiring signals are turned off in the ECU, though I’m not sure how that would affect the constant power that is still working.

Does anyone know of anything else to check before going to the dealer?

I know I had an issue with a dealer installed harness on a Dodge Durango. I went to go tow a boat and found the taillights in the trailer didn’t work at all. It turned out to be that the harness hadn’t been programmed so even though everything was physically connected properly the truck wouldn’t recognize having a receiver and harness. I had to bring it back in and the programmed it. On a Jeep GCL I had one installed by the dealer and they had a heck of a time installing it ( it took 4 days!!!) They installed it but it couldn’t get it to work. Ended up that there was a faulty wire in the harness so they had to order a new one. Not sure if either of these is your problem or not.

 

[spineb]

I know I had an issue with a dealer installed harness on a Dodge Durango. I went to go tow a boat and found the taillights in the trailer didn’t work at all. It turned out to be that the harness hadn’t been programmed so even though everything was physically connected properly the truck wouldn’t recognize having a receiver and harness. I had to bring it back in and the programmed it. On a Jeep GCL I had one installed by the dealer and they had a heck of a time installing it ( it took 4 days!!!) They installed it but it couldn’t get it to work. Ended up that there was a faulty wire in the harness so they had to order a new one. Not sure if either of these is your problem or not.

Ya, that's what this issue seems to be; the wiring and plug are in place, but the Jeep isn't programmed to send a signal. Guess it's going to be another trip back to the dealer...

 

[RichSNJ]

I have a ‘22 GCL Overland with the trailer-tow package from the factory.

I am not receiving any signal from the tow wiring, except for constant 12v power on the positive (+) pin located on the 7-pin connector. None of the other pins are getting any signal, nor are any of the pins on the 4-pin connector.

I could have sworn that everything worked fine last summer and I haven’t made any modifications since. I checked the 5 fuses that the owner’s manual mention “towing,” and all are fine.

The only thing left I can think of is that the wiring signals are turned off in the ECU, though I’m not sure how that would affect the constant power that is still working.

Does anyone know of anything else to check before going to the dealer?

I once had a problem with my '19 GC where the left turn signal on my trailer wouldn't work. I wound up replacing the entire light assembly on the trailer and it still wouldn't work, so I thought I was going to have to rip out my trailer wiring harness and redo it all. Before I did that I started to look for other options and I probed the Jeep connector and the circuit was dead. I discovered that each of the lines of the factory harness are individually fused. I had a blown fuse on just that circuit which was in the power distribution box under the hood. I assume that the wl's are the same, so I would definitely check the fuses before you go too crazy.

 

[spineb]

I once had a problem with my '19 GC where the left turn signal on my trailer wouldn't work. I wound up replacing the entire light assembly on the trailer and it still wouldn't work, so I thought I was going to have to rip out my trailer wiring harness and redo it all. Before I did that I started to look for other options and I probed the Jeep connector and the circuit was dead. I discovered that each of the lines of the factory harness are individually fused. I had a blown fuse on just that circuit which was in the power distribution box under the hood. I assume that the wl's are the same, so I would definitely check the fuses before you go too crazy.

Thank you. Do you happen to recall roughly where those fuses were located? Were they inline fuses or part of the power distribution blocks? The manual for the '22 lists 5 different fuses related to the "Trailer tow module," but when I checked, all were working.

 

[RichSNJ]

Thank you. Do you happen to recall roughly where those fuses were located? Were they inline fuses or part of the power distribution blocks? The manual for the '22 lists 5 different fuses related to the "Trailer tow module," but when I checked, all were working.

On my '19 the fuse I replaced was under the hood. The wl's may be different though as they've also go the fuse box under the seat for rear end things, so it wouldn't surprise me if they moved it down there. I thin there is a listing in the manual stating what all the fuses are in all three boxes.