We were supposed to leave on our camping trip tonight. As we headed out I noticed the brake controller was showing it didn't think the trailer was attached. However all the light worked including turn signal and brake on the trailer. We stopped at AZ and bought a new one. It was the samething, didn't recognize the trailer was attached. I have never had a problem with my brake controller. What could it be? We are back home till I can get this figured out. Any help would be greatly appreciated. Thanks.
Brake Controller Problem
- Thread starter rtheo1229
- Start date
IllogicTC
Member
- Dec 30, 2013
- 3,452
I've changed your thread title to tell people what they're about to be looking at when they come in here.
Well my first thoughts are out the window since your controller has already worked fine before (first thoughts were hooked up right? Controller bad? But you replaced the controller)
I suspect either wiring heading toward the trailer harness plug, or wiring in the trailer itself. Is this the same trailer you've hauled before, and the controller worked okay? Do you have any people around who also have a trailer that can utilize a controller? If so, you can ask to hook up to theirs just to see if it recognizes it, to help rule out wiring on the truck itself. From there, I'd point to the trailer wiring. With trailers usually getting propped up for weeks or months at a time before moving, sometimes rodents or natural aging or something else could have affected it.
Well my first thoughts are out the window since your controller has already worked fine before (first thoughts were hooked up right? Controller bad? But you replaced the controller)
I suspect either wiring heading toward the trailer harness plug, or wiring in the trailer itself. Is this the same trailer you've hauled before, and the controller worked okay? Do you have any people around who also have a trailer that can utilize a controller? If so, you can ask to hook up to theirs just to see if it recognizes it, to help rule out wiring on the truck itself. From there, I'd point to the trailer wiring. With trailers usually getting propped up for weeks or months at a time before moving, sometimes rodents or natural aging or something else could have affected it.
This is the same trailer I have been towing for about a year now. I took it to Camping World to have it's yearly inspection. Only problem they found was it needed new tires. I put the trailer up on jack stands and took the old ones to the tire place, got new tires, put them back on. The brake controller was working two weeks ago now nothing!
IllogicTC
Member
- Dec 30, 2013
- 3,452
Check these fuses:
Underhood fuse block:
Fuse 4 (10A)
Fuse 32 (30A)
Fuse 19 (30A)
Fuse 50 (10A)
Fuse 51 (10A)
Rear fuse block:
Fuse 42 (10A)
Some of these fuses should have absolutely no bearing on your issue, but may as well run through all the fuses related to the trailer system. It's best to use a multimeter to test the fuse rather than visual inspection unless it looks obviously blown.
If all of these fuses check out, then it's wiring test time. When they do trailer inspection, they hook up a connector and check the lights, right? Do they also do a test of the brake wiring, or do they just look at the brake pads?
You can try inspecting the trailer wire harness wiring. Inspect the plug itself for any corrosion or contacts which are out of place. Inspect the back of the plug for any loose or frayed wiring. On the back, you should see a dark blue wire. This is the wire that runs up to the brake controller you've installed, I do believe. Trace the wire as well as you can and inspect it thoroughly. There is also a white wire coming from the trailer connector plug, that is your ground wire. Also inspect this thoroughly and ensure a good contact, it grounds out on the rear frame crossmember.
I'd still suggest seeing if you have any friends who have a trailer that does the electronic braking deal and ask if you can plug into it. You don't have to haul it or anything, just literally do the plugging in and whatever else is needed to get the controller to try recognizing a trailer is on there. It is a good first-step if such an option is available as you can test all vehicle wiring in one shot. If not, it's time to trace wire
Underhood fuse block:
Fuse 4 (10A)
Fuse 32 (30A)
Fuse 19 (30A)
Fuse 50 (10A)
Fuse 51 (10A)
Rear fuse block:
Fuse 42 (10A)
Some of these fuses should have absolutely no bearing on your issue, but may as well run through all the fuses related to the trailer system. It's best to use a multimeter to test the fuse rather than visual inspection unless it looks obviously blown.
If all of these fuses check out, then it's wiring test time. When they do trailer inspection, they hook up a connector and check the lights, right? Do they also do a test of the brake wiring, or do they just look at the brake pads?
You can try inspecting the trailer wire harness wiring. Inspect the plug itself for any corrosion or contacts which are out of place. Inspect the back of the plug for any loose or frayed wiring. On the back, you should see a dark blue wire. This is the wire that runs up to the brake controller you've installed, I do believe. Trace the wire as well as you can and inspect it thoroughly. There is also a white wire coming from the trailer connector plug, that is your ground wire. Also inspect this thoroughly and ensure a good contact, it grounds out on the rear frame crossmember.
I'd still suggest seeing if you have any friends who have a trailer that does the electronic braking deal and ask if you can plug into it. You don't have to haul it or anything, just literally do the plugging in and whatever else is needed to get the controller to try recognizing a trailer is on there. It is a good first-step if such an option is available as you can test all vehicle wiring in one shot. If not, it's time to trace wire
djthumper
Administrator
I would probably check the wiring under the dash. Especially if you didn't do it yourself and it was not soldered.
djthumper said:
After checking the fuses I did this. I found the brake control wire soldering has come apart. I butt spliced the two wire together and the brake controller still doesn't think the trailer is connected. I checked the voltage at the 7 pin plug and I have voltage there. I'm not sure what else to check.
Where exactly do you have voltage on the 7-pin connector? When you press on the brakes, does the controller put anything on the brake output? (assuming it's a modern Prodigy controller or similar) Those use a PWM signal so your meter might show anything from 1-10V on the DC scale. And it may also show something like 1-6V on the AC scale.
View attachment 33649
My impression is the controller is detecting the trailer brakes by sending a very small current (not a voltage) to the brake pin. If there is nothing connected, the voltage developed by this small test current will go near 12V. If the trailer brakes are connected, the test current sill go through the brake electromagnet that has less than ten Ohm resistance, and develop very little voltage. If the 7-pin connector has voltage on the brake wire, but the trailer brake ground is corroded or disconnected where it splices into the trailer light ground wire, that would also explain your symptoms.
If you have a 5-10 Ohm power resistor in stock, you could clip lead it to the trailer brake and ground pins and simulate the circuit to confirm the controller is working or not. Or as has been noted, try another trailer.
View attachment 33649
My impression is the controller is detecting the trailer brakes by sending a very small current (not a voltage) to the brake pin. If there is nothing connected, the voltage developed by this small test current will go near 12V. If the trailer brakes are connected, the test current sill go through the brake electromagnet that has less than ten Ohm resistance, and develop very little voltage. If the 7-pin connector has voltage on the brake wire, but the trailer brake ground is corroded or disconnected where it splices into the trailer light ground wire, that would also explain your symptoms.
If you have a 5-10 Ohm power resistor in stock, you could clip lead it to the trailer brake and ground pins and simulate the circuit to confirm the controller is working or not. Or as has been noted, try another trailer.
Attachments
The_Roadie said:
Im get ~7VDC across the ground and electric brake pin. However now when I turn the light one they all work but when I press on the brake the brake lights go out. I cannot find any grounding issues. Is it possible the ground wire is broken in the connector wire?
I would connect a battery jumper cable between the vehicle frame or some good ground, and the trailer frame or some good ground.
You can also check with a voltmeter from vehicle to trailer frames and see if you ever see anything other than zero volts. If you do - then there's a ground discontinuity somewhere.
You can also check with a voltmeter from vehicle to trailer frames and see if you ever see anything other than zero volts. If you do - then there's a ground discontinuity somewhere.
The_Roadie said:
That did it. I had a faulty groung wire in my 7 pin wire cable. With the jumper cables connected the brake controller recognized the trailer. With it being Sunday no camper store nearby were open. I took a piece of 16 ga wire and grounded it on the trailer and the Voy. Brake controller still recognizes the trailer. I will stop and pick up a new cable and connect tomorrow. Thank you everyone for your help.
