RV Tech,
Have you had any dealings with the Ford IBC? Problems with this unit pop up regularly on the RV forums. I have had intermittent either "Wiring Fault on Trailer" or "Trailer Not Connected" for the past 3 years. Ford has looked at it and declared the unit working; RV techs have looked at the brakes and say they are working. Yet, whenever the techs get the system working, it later fails somewhere down the road.
I have had the magnets checked--I have had both wiring harnesses replaced--and I still have the problem. Right now, I have NO brakes with the message "Trailer Disconnected" immediately after applying the manual lever on the IBC.
I can get the brakes energized by jumping the hot lead to the brake lead; I have power to both plugs on the truck; I have power at the brake line connection in the trailer junction box; but still the brakes don't work.
I really don't want to pop for another IBC only to have the same problem.
I have tried to find/check the grounds--what I have located seem to be ok.
Any ideas?
Thank you,

Joe

 

I would hook it up to a different trailer first so you can see if it's the trailer or truck.

A few years ago I had similar problem and and it ended up being the cord end on the trailer cord, it tested OK but it wouldn't make a good connection all the time. I had this interment problem a couple of years before I found it, I went to a different style of cord end that didn't have the flimsy spring loaded connections.

Denny

 

We also have seen lots of the inside of the truck's 7-way connector corroded on the inside and the ground wire (and others) broken......

 

Thanks for the ideas, but both ends are new and the trailer end looks like the one on the right above. Originally, I had to jiggle the wires in the jct box and/or retighten the wire nuts. That would work temporarily, so I thought I had found the solution. Had the grounds redone, then later the new harness put on.
The trailer has lately had enough braking power to hold it with the manual lever, to test pull the hitch. But going down the road and using the lever, very little drag noticeable.
Yesterday, after having the trailer on a jobsite for a month, hitched up and pulled ahead to test the hitch--no braking at all, and message "Trailer Disconnected"
Right now, I have the underframe connector apart, not sure if there is a problem or not, hard to see it correctly. Going to clean it up good, and try to freshen the contacts, then reassemble with dielectric grease.
By the way, this connector has no rubber boot on it, nor does it seem to have a clip to hold it together. Anyone know if it should have a water cover on it? Or a locking clip?
Does anyone know how the IBC works to know about the electrical connection--because I have gotten 2 messages at different times: Trailer Wiring Fault, and Trailer Disconnected.
Joe

 

Sure, plenty of ideas. First, do not spend another penny until that is done.

Now to state my bias clearly, I do not like the IBC. I think folks make too much out of what it is and start troubleshooting as though they are dealing with a completely different animal. I also do not understand why, if you took your truck and trailer to an RV technician they did not troubleshoot both as it takes only minutes with the proper equipment. If both truck and trailer truly check out independently, it is a connection issue, pure and simple.

Now lets get the trailer out of the way first. Leave your trailer hooked to your truck, but with the seven pin cord unplugged. With a fully charged battery on the trailer, pull out the pin on your break away switch. Next get in your truck and try to pull your trailer. Can you move it? The trailer brakes should be locked or nearly so on your trailer with the pin out, if they are adjusted correctly. If they are working, you are done thinking about the trailer, at least for now, but be sure to put the break-away pin back in or you will melt the wires. They are too light a gage to carry the full amp draw of the brakes for very long.

Now for the truck-to-trailer, I am guessing you are taking your measurements using voltage (which is almost worthless). Do you know how to take an amperage reading through the trailer brake lead at the J-box? Your meter will have to be capable of reading at least 15 amps or you will blow the fuse in the meter. After you answer this, I will go further.

Steve

 

Joe, please stop for a minute. You are making this way too hard. The IBC is looking for a complete circuit and is not finding the resistance from the brake circuit on your trailer. You can test without a trailer by simply going and buying a single magnet like the ones on your trailer and using it on the brake pin and ground of your seven pin on your truck.

Steve

 

Steve,
Thanks for taking the time to clarify several things for me. I never was able to take my trailer with me to a Ford dealer, but they used a tester plugged into the bed plug and hooked up a computer--it showed the IBC to be working correctly. One of the mobile RV techs took the underframe connector apart and cleaned everything and put it back together. He firmly believed the trailer is ok--we drove around and the manual control would lock the brakes. All was ok for a day, then a repeat of the trouble about 300 miles down the road.
The female end of the underframe plug looks clean, and there is plenty of dielectric grease present. When the above teck took the connector apart, he said lots of go bad because the contacts corrode or just move away from each other. I have had the plug wrapped with electricians tape, but the locking clip is broken, so might be wiggling apart?
In the other thread with pics of the plug, what do you do when it looks like that? Ford says the harness is all one piece from engine to bumper and expensive to replace.
Again, thanks for some very logical advice.
Joe

 

Joe,

The reason I am trying to slow you down from buying anything until you know what to buy is because I see so many good parts replaced by both owners and technicians.

Now, from what you are describing, it sure sounds to me like you have a connection that is coming loose or you have feedback from one of the other circuits on your trailer or connection. I think that is why you have gotten two different messages on your display. That means a step-by-step working from the point where you have consistent power. If you can not get it out of the brake pin on your seven-pin on the your truck, you have to verify that you have power on the feed the brake pin from your harness. That means working on the backside of the plug.

I would agree with your RV technician in that I doubt it is a trailer problem, but verifying that takes perhaps 15 minutes at most. I actually have a tester on my truck I can plug into the seven-pin on the trailer and it verifies the trailer circuits without any other connections. The Achilles heel in the truck-trailer hook-up is the seven-pin connection.

Forget the trailer and focus only on the seven-pin. Again I do not know the harness arrangement for your truck, but you can tell easily if it is a one-piece harness just by looking. You can also replace the end on the truck with an aftermarket end. It is just connecting the correct wires to the new receptacle, but do not go there yet. It is premature. Everything for me is empirical, so I have no belief at all in anything I do not test and see with my own eyes. I get told dumb stuff all the time and spend my days working most of the time on things I have never seen before.

You can do this!

Steve

 

repair the easy stuff first. It will save you time and money.

 

Truer words were never spoken.

Steve