Discovered my 4 pin plug was not working when I hooked up my flat trailer. Called the dealer and they said my jeep may have to be programmed to recognize the tow wiring harness? Anybody heard of this before?

 

Undo the driver's side real lamp and see if the connections are connected.

 

Everything is connected. I put a 4 pin tester device into the rear receptacle and there is no power to the plug at the rear of the jeep

 

Do you also have the 7 pin harness installed?

When I added the 7 pin harness to the Jeep, the 4 pin stopped working. I opened up the driver's side rear tail light and rearranged the order of the plugs so they were all in series. That fixed the problem and now both the 7 pin and the 4 pin work.

 

Did you test the connections?

 

Im assuming youre talking about the 2 plugs that plug into the rear tail light assembly. My taillights work perfectly so how would this be a potential problem??

 

Maybe a bad wire harness.

 

Well there's a break in the current somewhere. If the wire harness plugged into the tipm, then I could see how you need to get the computer flashed, but basically you are just tapping into existing wiring with the 4 pin connector harness. If the tail lights work, but there is no power at the 4 pin connector, I'd check at the harness other end, namely the connectors at the tail ligjts.

 

I would check to make sure the ground wire in the connector is actually grounded. Use the continuity function on the multimeter to check continuity between the ground wire in the 4-flat connector and some unpainted thing such as a bolt connected to the chassis.