I have a 2002 4.7 L Durango with a factory tow package and a Reese Controller. Camping this weekend I noticed that the trailer brake lights would not come on... weird. It was just a short trip and anxious to get out to the lake, we made the trip. All other lights worked fine. Got to camp later that day I tried fiddling with the lights and noticed that none of the D's brake lights light up including the top. But if I manually activate the trailer brakes using the switch I get lights both in the D and on the trailer. Thinking it is the stop switch at the pedal I pull it out and ohm test it according to the service manual and it checks out. The FSM mentions that the Combination Flasher has a Brake Light Output in the relay so I replace it... Presto, I now have lower Brake Lights on the D, but they won't turn off. Still no top light, still no trailer brake lights, or power at the plug, and my Trailer Brake Controller is active, locking the trailer brakes.

Any thoughts, I put the old Combination Flasher back in to get home and manually actuated the trailer brakes to get lights when I needed them and all the other lights work normally.

 

do the lights work without the trailer connected? this will tell is if the issue is on the D or on the trailer

 

No they did not...

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Here's what I have so far. I double checked my fuses and # 5 was blown, replaced and I now have left and right brake lights and brake signal at my controller. I get 12V to my Upper lights but all three are burned out to a black/silver color. I still have no power at the trailer plug when brakes are applied on either the left or right trailer wire. Turn signals work.

I also seem to have a short in the White/Tan brake line. Testing resistance from Wh/T to ground gives 0 ohms so far checked at the upper brake lights, the right tail and on both L&R on the trailer plug. I don't think this is normal.


Any thoughts on where the short might be. This may have been what blew my fuse on the D after using the brake controller. I still have the issue that if I plug in my new combination flasher that I got, my brake lights turn and stay on despite what state the pedal is in.

I hate electric problems

 

so the bulbs in the third brakelight housing sound to me like they are burnt out just replace them and be done with it (although you probably came to this conclusion already)

as for the short in the fuse, if it shorted out when you hooked up the trailer id imagine the short is on the trailer

 

Yes, it shorted out while running the trailer, but right now, the trailer is not hooked up and I still have a short somewhere on the wt/tan brake wire. I've disconnected the wires at the rear hatch, now to find where the tow package wiring plugs into the harness.

Still doesn't explain why the brand new combination flasher makes my brake lights come on when plugged in.

 

it connects circuits that are affected by the short, either that or the new combination flasher itself is bad, it most certainly can happen

 

Did you ever resolve the problem of the new combination flasher keeping the brake lights on? I have the same problem on my 2002 Durango.

 

Have some weird stuff happening with my 03. Have two other trucks I use for towing ... Dakota and a Ram. Have 3 trailers. Everything works fine with Dakota and Ram with all trailers on 7 pin connector. When I try to use the Durango and plug any of the trailers to it the first thing that happens when I step on the brake pedal the instrument lights dim as if I had switched on the headlights. Second thing that happens, when I unplug any trailer the rear tailights stay on with the ignition turned off.

Durango is SLT+ with factory tow package.

Hoping someone else has found any weird factory wiring on these trucks and can pass on some knowledge, like where to start?

TIA

Fred

 

on my issue, I replaced the fuse as well as all of the bulbs in the brake system. Took the combination flasher back to napa and put the old one in. everything works perfectly. the only quirk is my wht/tan wire still has a short to ground some where in it.