Started getting TBF & check trailer alerts on the dash and the brake controller lights up 5.0 when NO trailer is attached....and the trailer lights don't work much when there is a trailer attached.
Cleaned out the truck end of the harness with electrical cleaner. Lights worked this time, but am still getting fault alerts when I drive without a trailer attached.

Am going to check all the fuses. If you have any other suggestions please chip in. AND...if I need to replace the controller and or harness, what does the labor hours look like? It's a tough row to hoe when you're paying $100 an hour or more to decide do I just replace it all or will a mechanic spend 10 minutes and find the fault or 3 hours searching for the problem and then still have to pay for the removal and installation of a new harness. Your thoughts are appreciated!

 

Fuses are clean and good....

 

If you have false faults on the trailer brake controller you can send it in to Ed at FICMrepair.com - It'll be about $100 to check and repair your TCB controller. Not at all
hard to pull the module... it pulls out of the dash and there are two plugs to remove on the module to get it out. I sent mine in because I was getting a TCB fault and a dinging sound. Sorry, but I have re-installed it but haven't pulled the RV yet this year. I WAS getting the fault and ding even without the RV connected and no longer do.

 

It may be the controller, but before going that route, go under your truck behind the seven pin and unplug it. Check and clean the connections there, unless you have already done so as that is one of the places which can cause problems. I do not think this is a harness issue.

While you have the seven pin unplugged, leave the portion under the truck unplugged and see if that makes a difference.

Steve

 

I've used the truck hard....9 years in Wyoming, 2 in Alaska and I figured maybe the rain, snow dirt, road solvents and salt etc may have created the issue.....so yesterday I replaced the receptacle.....haven't driven it yet, but have to go to town in a while....if I get the indicators then I'll know it wasn't the plug...lol....I'll advise....thanks for the excellent suggestions.

 

Here was the basis of my suggestion. The controller is not telling you whether or not you have a trailer. All it tells you is whether there is a complete circuit between the brake lead and ground. If anything completes that circuit, you will get a trailer signal or an erratic signal. Thus said, first eliminate the possibility that crud in the plug is completing the circuit. Once you have done that, then think in terms of the controller.

If you disconnect from the seven pin on the truck and then just leave the pigtail to the plug hang, you should have an open circuit (provided it is clean and dry). If the problem goes away, it was the connection at the seven pin. If you still have the problem, then think controller.

Steve

 

Well......within a half mile of driving the check trailer light, TBF light and the 5.0 on the controller started going off intermittently. Drove home and hooked onto my utility trailer...brake/emergency/turn signals all worked, but not the running lights.
I don't need the trailer brakes...I don't haul anything big that the truck brakes can't easily handle and I don't tow very often either. If I pull the brake fuse would that have any effect on the lights? I think I'll just splice into the truck's running light harness and attach that to the new plug....after I test the plug of course...."why aren't you doing that now?" its windy as hell outside...lol...20 gusting 30, so I'll wait till things calm down tomorrow or whenever...supposed to get snow tonight and tomorrow and I'm in no rush. :-)

 

Snow? Man we had 82 degrees yesterday. No the brakes have their own fuse. Pulling it should not affect anything else.

 

Thanks Steve...yeah it's hit and miss here...close to 70 the other day...here's a question for ya regarding the controller...why so many wires and two plugs??? And yet only one wire actually goes to the trailer brakes!

 

ELECTRONICS, FNG. Electronics! Ford's trailer brake controller is also tied into the the truck's braking system. It will actually pulse the trailer's brakes if the truck's anti-skid is actuated.... The ECU in the truck is coupled to the TBC so they need the extra wiring to complete all the circuits together. One of the plugs goes to the trucks own wiring circuit and the 2nd one goes to the 7-way on the bumper.

 

Thanks BP! Yeah, makes sense when you explain it....thanks for your service too....have you had that issue with your 05?

 

One very similar... my controller was occasionally flashing no trailer connected every once in a while - then the prob started happening more frequently. I probed every wire going to the 7-way while someone wiggled them all the way back to the RV brake wires going in to the wheels. I could never find the problem with any of the wires. My 7 way is inside the bed of the truck too, so NO corrosion inside the 7-way plug either. The controller was my last resort so I sent it in over the winter to have them do any repairs. I haven't had the RV hooked up yet this spring so I REALLY don't know if the problems is resolved. I will post the results when I finally get around to trying it out. I think that they simply send a different repaired controller out the same day they get one for repair. It was back to me inside of a week!!!