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Brake Controller failure

7_3_psdman
Explorer
Explorer
I am having an intermittent problem with the braking system from my 2000 Ford truck to my 2009 fifth wheel.
The trailer pigtail has to be plugged in before the Pilot brand brake controller will show a red C otherwise it just shows a red dot.
While towing down the road the brake controller looks like it drops out and quits showing any connection and I lose the brakes and lights on the trailer.
The problem is that I don't know whether it is in the controller or the truck wiring or the trailer wiring.
I have a lot of time to find the problem right now if I knew where to start. I have a meter and a test light.
We hadn't towed the trailer for a few years until we took the last trip about 500 miles from home and I didn't know that I lost brakes until we took the exit off of the big highway. The campground was only a couple of miles off the highway and I noticed that the controller wasn't reading while the wife paid for the site.
Anybody know where to start looking at the problem?
15 REPLIES 15

laknox
Nomad
Nomad
7.3 psdman wrote:
I replaced the pigtail wiring harness on the front of the trailer. I had read the reviews and knew that the Chinese use a different color code for their wiring. I plugged the wiring harness into the truck connection and then used a couple of small jumper wires and figured out the color pattern from the pigtail wires. NO PROBLEM. I think the Chinese wired my trailer too.
I installed a new towing harness on the truck and a new brake controller too.
The whole job cost a little under $140. Not bad when you figure the number of years that I have been towing the fifth wheel around.


Cr@p. The Chinese probably would have done a better job, though the wiring itself may have been suspect. Lots of incentive to do a good job when the alternative is likely a beating, at minimum.

Lyle
2022 GMC Sierra 3500 HD Denali Crew Cab 4x4 Duramax
B&W OEM Companion & Gooseneck Kit
2017 KZ Durango 1500 D277RLT
1936 John Deere Model A
International Flying Farmers 64 Year Member

7_3_psdman
Explorer
Explorer
I replaced the pigtail wiring harness on the front of the trailer. I had read the reviews and knew that the Chinese use a different color code for their wiring. I plugged the wiring harness into the truck connection and then used a couple of small jumper wires and figured out the color pattern from the pigtail wires. NO PROBLEM. I think the Chinese wired my trailer too.
I installed a new towing harness on the truck and a new brake controller too.
The whole job cost a little under $140. Not bad when you figure the number of years that I have been towing the fifth wheel around.

enblethen
Nomad
Nomad
Some trucks have a harness that plugs into the back of the seven pin. The ears come loose that holds it in tight.
Is there another trailer you can plug it into to test the receptacle?

Bud
USAF Retired
Pace Arrow


2003 Chev Ice Road Tracker

7_3_psdman
Explorer
Explorer
I was disappointed that the tow vehicle circuit tester doesn't mimic having the trailer hooked up. The tester showed that there was no power to the backup lights. Everything else works according to the tester and the I double checked with the meter and no power to the center post. The truck itself has backup lights. I checked the fuses and relays under the hood and they all work. I am thinking about buying a tow harness for the truck. But I think I will take the old one off and look at it first to see if a wire came loose.

7_3_psdman
Explorer
Explorer
With this being an intermittent problem I was wondering if I buy one of those 7 blade testers can I leave it plugged in until I see that the numbers drop out on my controller and then go back and read what the tester diagnoses? That is what I have in mind right now.

LadyRVer
Explorer II
Explorer II
I had an intermittent problem with my brake controller showing the now brakes when rolling down the road. Turned out to be the plug on the trailer end.

7_3_psdman
Explorer
Explorer
I made sure that the plug and truck connection were clean and lubed before we towed it home and that the cap was holding the plug in place. The plug has always fit a little loosely in the truck connection.
I have thought about changing the pigtail and the truck connection and or the brake controller but then I think that it might just be a grounding issue or a loose wire that I haven't found yet.
Social distancing is keeping me from trying to tow a different trailer with a seven point plug right now. If I did that and had the same problem at least I would know that it is a problem on the truck end of it.

ppine
Explorer II
Explorer II
The connection with the 7 pin can be loose or corroded. I spray it with lube and plug it in a few times and pull it out. Then the controller works.

laknox
Nomad
Nomad
I added a 2nd 7-pin connector in my truck bed and it's a =very= tight fit to get the trailer plug in far enough for the cap to catch the nub on the plug. If I don't get it all the way in, it doesn't take much for the plug to back out and lose connection. The bumper plug isn't quite so bad, but it can also give me problems if I'm not careful. Given that you haven't towed in a while, make sure the contacts on both plugs are clean.

Lyle
2022 GMC Sierra 3500 HD Denali Crew Cab 4x4 Duramax
B&W OEM Companion & Gooseneck Kit
2017 KZ Durango 1500 D277RLT
1936 John Deere Model A
International Flying Farmers 64 Year Member

Michelle_S
Explorer III
Explorer III
If you are really losing the trailer lites then I would say it's not the controller, but an issue with your wiring between the truck and trailer.
Might be worth replacing the Pig Tail first, and it that does fix the problem consider replacing the receptacle on the truck.
2018 Chevy 3500HD High Country Crew Cab DRW, D/A, 2016 Redwood 39MB, Dual AC, Fireplace, Sleep #Bed, Auto Sat Dish, Stack Washer/Dryer, Auto Level Sys, Disk Brakes, Onan Gen, 17.5" "H" tires, MORryde Pin & IS, Comfort Ride, Dual Awnings, Full Body Paint

jdc1
Explorer II
Explorer II
That problem is usually caused by the connection between the truck and trailer. The spring tension at the plug loses it's tension. I've had to use a screw driver and pry the inside of the connectors enough to get more contact. And, I now use small bungee cords to hold the connector (trailer side) tightly to the truck receptacle.

joelc
Explorer III
Explorer III
This won't solve your problem, but it helped me. Be sure all your connectors are clean and put some dielectric grease on them. This will help with the connection.

7_3_psdman
Explorer
Explorer
Thanks enblethen. Yes! It is working now but that could be because it is an intermittent problem. I didn't have a manual because the controller was in the truck when I bought it used. Thanks again!

enblethen
Nomad
Nomad
Here is manual:Pilot brake controller manual
There is a troubleshooting guide. Looks like you will need to check all the connections starting with power and ground to controller.
Did you try the manual control lever? what happens?

Bud
USAF Retired
Pace Arrow


2003 Chev Ice Road Tracker