Trailer Brake Controller (TBC) says "Trailer Disconnected" ...HELP!
 

Okay, I've done several searches and I am no closer to finding the problem. I know the default answer is "must be a wiring problem with the trailer" and I am not opposed to that answer, but let me tell you what is going on and what I've tried.

I just got my '06 F-250 PSD with factory TBC a few weeks ago. I have had the trailer for about a year and used it regularly with my old truck ('01 Chevy 2500HD with aftermarket trailer brake) without any problems.

I am about to do a cross country trip with my 20' car hauler so I wanted to do some around-town testing just to make sure there were no hidden tranny problems before I get in the middle of nowhere and find them. So, I hook up the trailer to the truck and the lights work, but the TBC does not see the trailer. I do not get any warnings or errors messages... it is no different than if the trailer wasn't plugged in at all. If I use the manual slide, I simply get the mesage "Trailer Disconnected" which goes away after a few seconds.

Here is what I have done to trouble-shoot:

1. Checked all of the trailer-related fuses
2. Crawled under the trailer and briefly checked wiring
3. Found 3 other brake-equipped trailers and tried hooking them up to my truck. Now, with these I did not connect the tongue, just the wiring.
4. Hooked the trailer back to my old truck, worked fine.

I understand that the Ford TBC is more "sophisticated" than the aftermarket unit that I'm comparing to, and the problem could still be with the trailer. However, that would also mean that the 3 other trailers I tested have faulty wiring too.

I am also using an adapter from the small round pin connector (trailer) to the flat pin (truck). However, I use this same adapter on the old truck without any problems, and the brake control wire is located in the same pin connector on both.

I will add one last tidbit, from my searching I have seen that some people have wires disconnected for their TBC from service work being performed to the engine or tranny. Shortly after I got the truck, it went in for warranty work on the PSD and they did close to $4k worth of warranty work (turbo, egr, etc). Could it be possible that the didn't reconnect something under the hood?

Any help would be appreciated because I leave in just over a week and I really would like the security of the trailer brakes for the long haul.

Thanks,
Adam

P.S. Yes, I did say the old truck was a Chevy. I am really not a Ford OR Chevy guy. However, I will say this.... after having 3 Chevy's, driving an F-250 once it made me wonder why I ever bothered with the Chevys at all. I am truly impressed with the overall fit and finish, as well as the ride of the F-250 compared to my old 2500HD.

my 06 F350 does the same thing from time to time,I have found it to be dirty terminals in the trailer plug I insert the plug several times while wiggleing it up and down,then it's good for several months,anyway that is what makes mine work,just a thought.

OK, I have a like but different problem with my F-550. It works as it should when a trailer is hooked up to the rear receiver hitch, however, From time to time when I am pulling a trailer with the use of my BW goose neck hitch I will get the trailer disconnected message. This will usually happen when I first hook up or going down the road and either hit a rough patch of road where the trailer bounces or a big bump. The only thing I have been able to account the message to is the lack of good ground from truck and trailer due to lack of hitch to truck contact during the bounce. However during the disconnect message the trailer brakes will activate and do their job.
Could it be that you need to clean a little dirt and grease off of your trailer coupler and allow a better hitch ground to complete.
And yes I know that if both the trailer and truck wire harness are wired with the ground wire properly attached this problem shouldn't exist. But it also seems that in a high percentage of wire problems on these trucks a poor ground can be found to be at fault.
Good Luck

I rented a trailer, had the same problem it was in the wiring that connects to the truck(in the black connector)the wires where corroded. Cleaned it, reconnected all good.

You shouldn't depend on the hitch (whether 5'er or under bumper) for a ground point!! Insure that the trailer plug is wired correctly... see here.

https://www.ford-trucks.com/forums/59...g-diagram.html

Also look at the rest of these trailer/tow Hints! Good reading.

I guess I should add that I did hit both the truck and trailer connectors with WD-40, even though they both looked good.

GTXgp,
I bought a gooseneck for my 06 f350 sd psd and when I hooked up to the integrated TBC, I got the same indications, erratic running lights, and a completely unreliable braking response. Here is what I found out:
First, and formost, trailer brake systems draw some goodly (sic) amounts of juice and since the juice starts at the negative, runs thru the system and ends up at the positive, the negative supply line needs to be hefty. Unfortunately, I found the trailer connection a week supplier of a solid ground. Also, a lot of trailers make up the lack of a solid ground through the ball connection. Bad Idea!!!
Solution, I drilled a 3/8" hole through the back pillar at the top nearest the top of the bed. This was drilled out of site, out of the way from interference, and right behind the left brake light. After popping the aft-left bed cover cap, I ran a bolt thru the hole with an inch of thread sticking thru to the bed. Then, I ran a six gauge wire down the pillar and grounded in to the frame. Now when I pull my gooseneck, I run a six gauge wire from the gooseneck frame to the bolt in the bed giving me the greatest ground possible.

Second, the integrated brake controller is sensative to different types of brake systems. Are your trailer bakes electric, or electro-hyraulic? Experience shows the integrated brake controller does not like the electro-hydraulic set-up. If you have this, contact etrailer.com and order the voyager brake controller and seperate wiring harness. this will solve the issue for the trailer, although it might not answer your questions about why the IBC isn't compatable with your trailer. If you want pictures, email me. Hope this helps.

An extra ground is not a bad idea.

It is an all electric setup.

Just curious, you say you're using the flat plug on the truck, right?

If this is the case, then this is your problem, the 4-wire flat only has left, right, running lights, and ground. There is no wire for electric brakes in that plug. For that, you must use the 7-way round plug on your truck. Not sure what configuration you have on your trailer, there is a 4,6,or 7-wire plug available in a round configuration. However only the 6 and 7 wire plugs have brakes available. If you were using a 4-way flat on your old truck, then I can't imagine how it ever worked, unless it was a "custom" wiring job.

If you can, either take a picture of the plug on your trailer and post it or at least give us a detailed description of it. My gut feeling is that your best bet is to rewire the trailer with a proper 7-way plug an dthen you won't have any problems at all.

The flat connector does not have brake pins.

Rob

Sorry, not the 4-pin. I know a little better than that :-X18

I guess I should have meant that I am using an adapter from the round-pin style connector to the blade-style that the truck has. I used this same adapter on my previous truck.

I am starting by bringing the truck and trailer to a trailer shop tomorrow for them to check both out and tell me what I'm missing.

let us know what they find. also, let me know if you want pix of the wire, although I doubt you will need it.

Always use the white wire on the trailer side, too. Just bolt it to the frame to ensure a positive ground.

#1) Do your adapter pins match your truck pins? What would it hurt if you cut the 7-round-round off and replaced it with a 7-round-blade?

#2) What kind of brakes?

On my 6 pin to 7 pin adapter, the trailer brake and the 12 volt supply line pins can be reversed. Didn't know about this until I hooked up a buddies trailer and had full brakes all the time. The two pins swapped real eazy and was in the instructions for the adapter and was on my way. If you are not supplying 12v battery power back this could be your problem as it wouldn't apply the power to the brakes as mine did. Sorry, right now I can't tell you wich pins but will try to find it.

Hope this helps.

Well, I guess I shouldn't have doubted the truck to begin with. Apparantly the trailer wiring AND brakes were completely fubar'd. Replaced the wiring, replaced the entire brake units, and everything works just fine now :)