I Have a 2000 F350 CCLB 7.3. I am supposed to pick up a rental trailer tomorrow so I was installing a brake controller this morning. It looks like the previous owner had one installed but I never have. I'm not sure if it's hooked up right or not. I plugged into the factory harness under the dash and the indicator light didn't come on when I pressed the brakes. I checked the wiring harness under the dash and I have 12v on the positive and 12v on the brake wire when I press the brakes. So it appears I'm getting power to the controller. Everything on the 7 pin harness on the bumper seems correct. Positive 12v, turn signals work, running lights work, when the brake controller is connected the electric brakes pin has 12v and when I depress the brake pedal it drops to 0v. I'm not sure if that is correct or not. If that is correct, I'm wondering if the indicator light only comes on when the trailer is connected and the brakes are applied? If anyone could shed some light on this I would appreciate it. I would call the company for customer support but they aren't open until tomorrow and I was hoping to hash this out today

 

On my Prodigy 3 the light is off until you hit the brakes, then it is lit trailer on or not. So something is amiss there. What brake controller do you have?

 

Tell me what controller you are using as I want to go to the troubleshooting online. What you have is not correct, provided I understand what you are saying.

Steve

 

Forgot to say. If you have an electronic controller like a P3, use the manual slide to test output. You can't use the pedal and get an accurate reading.

Steve

 

I started with a Reese controller from tractor supply. When I had trouble I took it to my buddies 7.3 and plugged it into his and same thing, no light. So I assumed it was a bad controller out of the box. They didn't have anymore of those so I grabbed the next cheapest and that is a tekonsha voyager. I plugged it in and still no light. After I posted this I did some googling and realized that something is definitely wrong. One of the online q&a guys said to cut the blue wire and test it coming out of the controller. I still had 12v with no brakes pressed. I took the controller inside when it started to rain and hooked it up with some leads to a battery. With positive and negatives hooked up, I get 12v at the blue wire. So the only thing I can figure is somehow I won the lottery and randomly grabbed two bad controllers off the shelf or I have some kind of shirt that is frying the controller when I plug it in and causing it to not light up and send 12v to the blue wire. I would think even if there was a short, I would see a brief blink of light on the indicator before it dies

 

So not to be insulting, just asking. You have 12-volt+ on black lead and 12-volt- on white lead to controller?

Steve

 

Correct. Positive on the black wire, negative to the white wire

 

Man, I don't see how that controller is good. I just worked on a Voyager yesterday. If you go online, you can see the YouTube video on what should be happening. Before you plugged these controllers in, did you by chance check the voltage at the plug on your truck and again, not to be insulting, you were plugged into the plug just driver's side of center kind of behind the radio?

It just seems like such a long shot to have two bad controllers out of the box.

Steve

 

Yes the factory harness is what I plugged the store bought 18" wire bundle connector into. Then that wire bundle hooks up to the controller. Before hooking up the controller the bundle seems to test perfectly. Positive 12v, brakes only 12v when pedal is pressed, blue wire 0v. That makes me comfortable that I'm plugged into the right harness not to mention I would think it might be the only one under there that has that shape. I'm assuming the controller is essentially just a fancy switch. If that's the case, can you think of something that might cause it to fail closed and provide 12v to the blue wire?

 

Given the symptoms, the only thing I can surmise is somehow both controllers have a burned out relay internally after they were installed, but I have no idea how that could happen.

How about this. The red lead to the controller should only be hot when the brake pedal is depressed. Wonder if it was? The relays should be in the box under the hood. How do things look there?

 

when I test the red wire at the harness that comes from under the dash, I only have 12v when pedal is depressed. Is that what you mean? I was going to check under the hood but everything seems to be correct on the harness when testing. I'm thinking about grabbing a third controller tomorrow morning and trying it out of the truck with just a battery to see how it tests before I try installing it in the truck. I'll probably also call customer service to see if they can tell me if it would fail closed and cause the blue wire to have voltage

 

I don't know what is going on with the site. I am getting email of the posts, but when I go to the site they are not showing up on my screen.

Anyway, as near as I can tell you have done everything right and I have never seen anything like your situation before. I certainly have seen no light when the controller is powered, but that is when the controller has dies and there is no power down the blue lead in any condition. In the case here it is like the controller is wired wrong internally.

You might simply call tech support and ask em at the manufacturer's. I don't think there is anything you could do to cause this situation and I don't think you did. If the red lead was always hot until you stepped on the pedal, you would have power through the blue lead, but even then it should not burn out anything. The controller would simply think you were stepping on the brakes.

I wish I were there simply to see what is going on with these controllers. It is a lot more interesting than the usual controller questions. If the moderator moves this thread over to the towing forum under "towing: other", I am sure some of the other guys may jump in.

Steve

 

thanks for the help. If somehow I did happen to get two bad controllers, I might burn down tractor supply. j/k I'll update the post with the outcome tomorrow.

 

I don't subscribe to any threads so I don't get the emails but my screen shows new post in thread by x poster at y time and it does not show when I click on the thread. kefrko's 6:18 post is one example.

 

I have a tekonsha voyager and it will only light up with trailer plugged in with good wiring. Light is green to tell you wiring is good and orange/red depending on output when braking.