I've had this same issue before but with a different truck and different trailer.

We have a new F450 and a new toy hauler. This past weekend, I realized I have very little trailer brakes. I do landscaping and today, I realized I have very little braking power to one of my landscaping trailers as well. I must admit though, I've had trailer wiring issues quite a bit with the brand of trailers I've been using so that could definitely be a coincidence.

I took the 450 to the dealer today to have the 7-pin checked. He hooked up a device to see if there's power. Yes, there was. But honestly, this service guy knew very little about how trailer brakes work and how the Ford trailer braking system functions.

With both the toy hauler and the loaded down landscaping trailer, I have to run the brake controller on 10 just to get a little braking power to the trailers. When I slide the "test" lever over, its only a slight tug from behind. This should easily lock the brakes up but it doesn't even come close.

When I had this issue last year with my '09 F350, another dealer told me that even when I blow a fuse with my braking system, the Fords are designed to have "some" power to the trailer brakes to keep someone from being totally without. That makes sense but I'm not 100% sure its true. I will admit though, I do have "some" braking power to my brakes on my trailers but every fuse I can think of that has anything to do with the trailer braking seems to be fine.

Sooo, has anyone had any similar issue? Is there a better device to measure if the 7-pin is putting out adequate power? I want to be 100% sure its not the truck before we take the toy hauler back to the dealer. The toy hauler dealer is an hour and a half drive. If I drag the camper that far to have the brakes checked and then discover its not a camper issue, I'll not be a happy camper.

 

Not to hard to check with a clamp meter that reads DC amps. Clamp around blue lead to trailer brakes. 10 amps and above, electric is okay, something amiss with mechanical on brakes. Less than that and connection or truck problem.

If you find someone who has the emulator for trailer brakes and knows how to use it, it takes about five minutes to definitively answer your questions. Most RV dealers have the know how and tester, as do many mobile techs. Unfortuanely the built-in Ford system is really lacking when it comes to built-in diagnostics. Almost any after-market brake controller is miles ahead.

Steve

 

I had the same issue's. Started with brakes working pretty well. Then they were working maybe 50% (in a weeks time they decreased about 50%). Then they quit 100%. I found a bad connection in the junction box of the trailer. Got them back to 50%.

Tested the truck's 7 wire socket. All the light terminals worked, but the ground lug and the blue brake wire lug seemed weak. I replaced the entire socket after rigging a alternate ground through a jumper cable from the trailer to the frame of the truck. 10 mph in the driveway proved it was the ground lug of the truck socket, probably shorting to the trailer lug from water leaking in.

Curiously, all this started right after washing the truck. Also, at least on my large trailer, all the connections for everything are done with ordinary wire nuts. After miles of potholes and vibration, they just loosen up once in a while.

I did get a trailer emulator ( $25.00 ), saves a lot of time trying to figure out if the trouble is the truck or the trailer.

Dave

 

Good job. If you take the Ford seven pin apart, you will often find the ground pin in the plug almost completely rusts off on the back side. Water seal on back of plug is weak and grounding pin is in standard low position. It often almost completely rusts off inside female end on truck. May be why the plug is turned 90 degrees on the newer trucks so ground is no longer at the bottom.

As a side note, with braking problems. it is almost always the grounds. One of fastest ways to check at home is run a secondary ground between the truck and trailer so the ground does not depend on the seven pin. Doesn't require much to light lights, takes a good deal more to work the brakes.

I carry a fancier box with a long connector so I can actually sit in the driver's seat and read how much voltage you have at the plug and how many amps pass through the seven pin receiver on the truck to the brakes when the controller is activated, as well as whether all the lights are working without having the trailer hooked up. Very fast and very accurate. Its like having the trailer sitting in my lap with a multimeter spliced in the lines.

I do a lot of dealer deliveries on the lot and you would be amazed how many folks blame the trailer, until I hook up my box and show em what their truck's seven-pin is acutally putting out. Have had brand new trucks come in with bad seven pins on the truck. Unless it is a hack job, I don't see much problem with factory wiring. Usually the ground or the controller.

Steve

 

You can also have someone step on the truck brakes with the trailer connected. Then go to each wheel. Do you hear a buzz? If so then there is power getting there.

That is a quick check. Does not mean there is no problem but it is a start.

do the brakes on the trailer need adjusting?

 

That's what I'm trying to figure out. The Cyclone dealer is an hour and a half drive.

The brakes are the same weakness with my landscaping trailer. I'm strongly thinking its with the truck.

 

Do you have a multimeter for testing?

Steve

 

Second thought.

Hook up your trailer to your truck, and, with a fully charged battery on board your Cyclone, pull the pin on the break-away switch and try to pull the trailer. Your trailer brakes should be fully activated by the break-away and the trailer should be locked in place.

Can you move the trailer? If it is the same with the break-away pin pulled as with the truck, the trailer brakes may need a look-see. If you can not move the trailer when the break-away is activated, it is the truck or the connection to the truck, but you have removed the trailer brakes from the equation.

Do not have the seven-pin hooked up when you pull the breakaway or you may fry something in the truck and be sure to put the break-away pin back in or you will melt your wires with sustained activation.

If you have a multimeter that will read at least 20 amps, so you don't blow the fuse in the meter, you can also take an amp reading and will know if all the magnets are onboard when the brakes are activated.

Steve

 

Great idea with the break-a-way switch. I'll try that this weekend.

That's why you're the master technician and I cut grass.

 

You could just change the 7 wire socket. With your problem transferring from trailer to trailer, seems likely that the truck is the problem. Socket is around $10.00, and is actually a better design. All the wiring just goes through one hole about 5/8" or so, instead of individual holes for each wire. A little dab of silicone after the change, and no water can get in.

Dave

 

P.S.- Lot's of places sell trailer wiring supplies. Might find one close by.

Dave

 

Would always suggest diagnosis before treatment.

Steve