Trailer Brake Problem/Question

[tractorshopper]

My old brake box stopped lighting up long ago as I haven't towed a trailer with brakes in quite some time. It was a hand-me-down to begin with so after several years and not needing it, I didn't think much more about it.

Now, I have a trailer of my own with brakes and need to take my tractor to my brother's property to do some work. The trailer is wired for my truck with 7 flat pin and all connections are right. I went and bought a new brake controller and while I haven't hooked it to the trailer yet, I do not get a light on it (brake controller indicator light) at all while applying brakes. Should light red for "no trailer attached".

Fuse in fuse box is good. Brand new controller and brand new wiring harness for it. All connections made properly. When I had the trailer hooked up last week, all lights worked properly so I am getting proper power to proper wires at back of the truck. I'm a little perplexed and wondering if my old controller really wasn't the problem after all. Maybe some other possible wiring issue that would only affect the brake wire and not the others or maybe some power issue with getting the power to the controller?

 

[Dr Dave]

check the ground, most new controlers recomend running ground to battery.

 

[George2615]

It may depend on the controller you bought. My controller does not light up until the trailer is plugged in.

 

[radioman]

yup, same here as George2615. Mine doesnt light up till a trailer is hooked up and shows green only when I do "see" my trailer brakes conneection. Turns orange to red when brakes is engaged. How does yours supposed to work?

When I had a problem with controller, it was because of loose connection on truck/trailer plug or one time the wiring harness heated up and crumbled from exhaust heat. I just replaced the wire and moved it away from heat source.

 

[tractorshopper]

yup, same here as George2615. Mine doesnt light up till a trailer is hooked up and shows green only when I do "see" my trailer brakes conneection. Turns orange to red when brakes is engaged. How does yours supposed to work?

When I had a problem with controller, it was because of loose connection on truck/trailer plug or one time the wiring harness heated up and crumbled from exhaust heat. I just replaced the wire and moved it away from heat source.

Ok guys, hoping that's it. I'll hook it up tonight to see, but the paperwork said that it should light red if no trailer connected and brakes depressed unless it was referring to a different model. My old one said E1 whenever I hit the brakes with no trailer connected.

 

[mjw357]

Fuse in fuse box is good.

How do you know this? Looking at it won't always tell. And keep in mind that this circuit can be fed by another bigger circuit that may also be fused. Check your power connections with a test light or multi-meter. Sounds like there may have not been anything wrong with your old brake controller.

 

[Diamondpilot]

Hook the trailer up and check things. If no go get out he volt meter and check for proper voltage. Also, make sure you followed the wiring diagram. On many the black wire is the positive, the white wire is the ground, the blue wire is the brake out wire (to the trailer), and the red wire is the brake signal in wire (from the brake light circuit). Its not as simple as hooking the wires to the same colored wires.

Chris

 

[tractorshopper]

How do you know this? Looking at it won't always tell. And keep in mind that this circuit can be fed by another bigger circuit that may also be fused. Check your power connections with a test light or multi-meter. Sounds like there may have not been anything wrong with your old brake controller.

Fair enough question and point; thanks. I went through every fuse that has anything to do with lighting (both truck and trailer), trailer wiring, trailer brake wiring, brake wiring, brake controllers, etc, and pulled them and checked them and no damage. The one fuse listed for this specifically was one I had to purchase and install originally way back when I bought the truck and I was using a friends trailer and when I first installed the first brake controller. I had to purchase the specific wiring harness for it as well and a specific harness for the 7 pin for my truck and now the new harness for the new brake controller specific for my truck (2006 F-150). None are blown may have been a more accurate way of saying this. I need to buy a test light for sure and work from there. I too am thinking there may not have been a problem with my old controller after all.

I'm also beginning to wonder if there could be an in-line type fuse somewhere between the battery and the break controller harness. Like something external to the normal fuse box whereby I'm not getting power to the controller to begin with.

 

[tractorshopper]

Hook the trailer up and check things. If no go get out he volt meter and check for proper voltage. Also, make sure you followed the wiring diagram. On many the black wire is the positive, the white wire is the ground, the blue wire is the brake out wire (to the trailer), and the red wire is the brake signal in wire (from the brake light circuit). Its not as simple as hooking the wires to the same colored wires.

Chris

Totally agree with you on not hooking same color wires together :laughing:. Am hooking it up to the trailer tonight to test this out. The blue wire from the truck goes to a blue wire on the 7 pin trailer side harness that goes to a red wire to the brakes. All trailer lights and functions work properly and I'm pretty sure this is wired correctly too (I spent a lot of time on this about a month ago). I actually had to make sure the right slots went to the right trailer side slots regardless of color because the truck has one set of colors, the harness part of the trailer has another set of colors (some match, some don't) and the trailer wiring tied to the harness has a different set of colors again. All functions work perfectly and I traced them all out, so the only left over wire is the yellow (on the trailer harness (center pin)) which corresponds to a reverse light from the truck wiring (not to be confused with the yellow turn signal wire on the trailer that I think goes to red on the harness:confused2:. Anyway, I can tell you for certain that I had already made sure the right wires went to the right places.

What started me on this is that when my old controller worked (stopped several years ago), it gave me an E1 message everytime I'd depress the brakes when I did not have a trailer hooked up. New controller indicates that I should get a red light when no trailer hooked up and braking, and I'm not seeing any lights light up on it at all. Do you think there could be another fuse ahead of the contoller somewhere that would not be in the fuse box, but somewhere under the dash or under the hood? That's the only think I can think of right now in my limited understanding.

 

[mjw357]

Do you think there could be another fuse ahead of the contoller somewhere that would not be in the fuse box, but somewhere under the dash or under the hood? That's the only think I can think of right now in my limited understanding.

You might want to get on a Ford truck forum and start snooping there. Sounds like you've got it narrowed down.