Trailer Brake Controller Issues - Ford Disaster - Solved
06-01-2017, 09:04 AM
#11
If it's in parallel with the brake magnets, you have reduced the resistance the controller sees. The total brake resistance was 3 ohms before the resister was added (trailer magnets are often 6ohms each, so two wired in parallel are 3 ohms at the junction box) and you added another 3 ohm resister, IN PARALLEL with the brakes, you have halved the resistance and doubled the current. You should be reading 1.5 ohms, not 6 ohms.
http://www.electronics-tutorials.ws/resistor/res_4.html
Resisters in parallel have the relationship:
1/R1 + 1/R2 = 1/Rtotal
It sounds like the brakes on your trailer are wired in some kind of series/parallel combination or completely in series, that is making the resistance too high and the controller flake out. If any of them are in series, if you loose one brake, the rest stop working. Wiring isn't always a strong point for trailer builders, so I would have a closer look at how they are actually wired up. Many controllers are less "smart" than the Ford unit and don't care as long as some current flows.
4 trailer brakes, properly wired in parallel, should show 1.5 ohms at the controller.
The updated programming probably allows for a greater range in the allowed resistance which is why the disconnected warning stopped happening.
http://www.electronics-tutorials.ws/resistor/res_4.html
Resisters in parallel have the relationship:
1/R1 + 1/R2 = 1/Rtotal
It sounds like the brakes on your trailer are wired in some kind of series/parallel combination or completely in series, that is making the resistance too high and the controller flake out. If any of them are in series, if you loose one brake, the rest stop working. Wiring isn't always a strong point for trailer builders, so I would have a closer look at how they are actually wired up. Many controllers are less "smart" than the Ford unit and don't care as long as some current flows.
4 trailer brakes, properly wired in parallel, should show 1.5 ohms at the controller.
The updated programming probably allows for a greater range in the allowed resistance which is why the disconnected warning stopped happening.
The second is that most new electric brake magnets are 3.2 ohms alone as a single unit new. Two in parallel is half that so about 1.6 ohms total circuit resistance. The problem is they are electro-magnets and they change resistance pretty drastically when they are activated. It is a common mistake of a tech to try a total resistance with a digital ohm meter for total circuit resistance at the trailer connector (trailer side) and assume that reading means anything other than the circuit is complete for only one magnet. It is fine for gross wiring problems like severed wiring, but it is pretty much useless for a subtle circuit problem like this one.
The resistance test either needs to be done at each magnet individually with the wires unplugged, or even better a voltage drop needs to be done at each magnet with them activated. The advantage of the voltage drop is that it tests the circuit and the magnet all in one test. The disadvantage is that you need electrical access to the wiring at each magnet which requires tampering with trailer wiring near the wheels that should be sealed. Those tests also require a tech that knows what he is doing, and it isn't going to happen for free under an F150 warranty at a dealer.
An 2015+ brake controller with either flash will run single axle electric trailer brakes. I've done it. I could find the problem with the trailer here in less than 10 minutes if I could cut into sealed wires on the trailer (and fix later). The resistor will work fine, as you stated it is just lower resistance maybe similar to a two or three axle trailer.
06-03-2017, 11:51 PM
#12
If it's in parallel with the brake magnets, you have reduced the resistance the controller sees. The total brake resistance was 3 ohms before the resister was added (trailer magnets are often 6ohms each, so two wired in parallel are 3 ohms at the junction box) and you added another 3 ohm resister, IN PARALLEL with the brakes, you have halved the resistance and doubled the current. You should be reading 1.5 ohms, not 6 ohms.
http://www.electronics-tutorials.ws/resistor/res_4.html
Resisters in parallel have the relationship:
1/R1 + 1/R2 = 1/Rtotal
It sounds like the brakes on your trailer are wired in some kind of series/parallel combination or completely in series, that is making the resistance too high and the controller flake out. If any of them are in series, if you loose one brake, the rest stop working. Wiring isn't always a strong point for trailer builders, so I would have a closer look at how they are actually wired up. Many controllers are less "smart" than the Ford unit and don't care as long as some current flows.
4 trailer brakes, properly wired in parallel, should show 1.5 ohms at the controller.
The updated programming probably allows for a greater range in the allowed resistance which is why the disconnected warning stopped happening.
http://www.electronics-tutorials.ws/resistor/res_4.html
Resisters in parallel have the relationship:
1/R1 + 1/R2 = 1/Rtotal
It sounds like the brakes on your trailer are wired in some kind of series/parallel combination or completely in series, that is making the resistance too high and the controller flake out. If any of them are in series, if you loose one brake, the rest stop working. Wiring isn't always a strong point for trailer builders, so I would have a closer look at how they are actually wired up. Many controllers are less "smart" than the Ford unit and don't care as long as some current flows.
4 trailer brakes, properly wired in parallel, should show 1.5 ohms at the controller.
The updated programming probably allows for a greater range in the allowed resistance which is why the disconnected warning stopped happening.
I was a bit confused until I went back and read my original comment and realised I posted it a 6 ohm and not 1.6 ohms. That would be a typo on my part.
***Was going to edit the original post but looks like Admins have that functionality turned off...WTF!
Two problems here. One is that Gonzo stated that he has a single axle trailer, so you can have parallel, or series (without resistor), not both (series parallel).
The second is that most new electric brake magnets are 3.2 ohms alone as a single unit new. Two in parallel is half that so about 1.6 ohms total circuit resistance. The problem is they are electro-magnets and they change resistance pretty drastically when they are activated. It is a common mistake of a tech to try a total resistance with a digital ohm meter for total circuit resistance at the trailer connector (trailer side) and assume that reading means anything other than the circuit is complete for only one magnet. It is fine for gross wiring problems like severed wiring, but it is pretty much useless for a subtle circuit problem like this one.
The resistance test either needs to be done at each magnet individually with the wires unplugged, or even better a voltage drop needs to be done at each magnet with them activated. The advantage of the voltage drop is that it tests the circuit and the magnet all in one test. The disadvantage is that you need electrical access to the wiring at each magnet which requires tampering with trailer wiring near the wheels that should be sealed. Those tests also require a tech that knows what he is doing, and it isn't going to happen for free under an F150 warranty at a dealer.
An 2015+ brake controller with either flash will run single axle electric trailer brakes. I've done it. I could find the problem with the trailer here in less than 10 minutes if I could cut into sealed wires on the trailer (and fix later). The resistor will work fine, as you stated it is just lower resistance maybe similar to a two or three axle trailer.
The second is that most new electric brake magnets are 3.2 ohms alone as a single unit new. Two in parallel is half that so about 1.6 ohms total circuit resistance. The problem is they are electro-magnets and they change resistance pretty drastically when they are activated. It is a common mistake of a tech to try a total resistance with a digital ohm meter for total circuit resistance at the trailer connector (trailer side) and assume that reading means anything other than the circuit is complete for only one magnet. It is fine for gross wiring problems like severed wiring, but it is pretty much useless for a subtle circuit problem like this one.
The resistance test either needs to be done at each magnet individually with the wires unplugged, or even better a voltage drop needs to be done at each magnet with them activated. The advantage of the voltage drop is that it tests the circuit and the magnet all in one test. The disadvantage is that you need electrical access to the wiring at each magnet which requires tampering with trailer wiring near the wheels that should be sealed. Those tests also require a tech that knows what he is doing, and it isn't going to happen for free under an F150 warranty at a dealer.
An 2015+ brake controller with either flash will run single axle electric trailer brakes. I've done it. I could find the problem with the trailer here in less than 10 minutes if I could cut into sealed wires on the trailer (and fix later). The resistor will work fine, as you stated it is just lower resistance maybe similar to a two or three axle trailer.
06-04-2017, 10:12 AM
#13
Could this be the issue I had this past week? I rented a dual axle TT from the base, and the brakes would only work occasionally, and I couldn't get the wheels to lock up at all with the manual control, even with the gain all the way up.
It would work occasionally on the road, especially if I applied the brakes slowly and lightly.
Occasionally it would pulse the brakes as I was slowing.
Other times I would get a fault or no brakes.
I was going to give the Outdoor Rec folks some hell on Monday when I return it, glad I ran into this.
It would work occasionally on the road, especially if I applied the brakes slowly and lightly.
Occasionally it would pulse the brakes as I was slowing.
Other times I would get a fault or no brakes.
I was going to give the Outdoor Rec folks some hell on Monday when I return it, glad I ran into this.
06-07-2017, 07:34 PM
#14
Another possible cause for poor brake detection/operation is the 7-pin connector itself. It is a very poor design with a pigtail that goes between the main wiring harness and the back of the 7-pin connector. Even now that they have flipped the orientation moisture still gets in and results in false trailer disconnects or lack of trailer detection. I've found if I dry it as best as I can and use a contact lubricant that displaces moisture I will be good for a couple to few months. In a pinch I've just dried and reseated the connector a few times to get home.
Edit:
Forgot to mention this is the connection on the backside of the 7-pin connector itself.
Edit:
Forgot to mention this is the connection on the backside of the 7-pin connector itself.
06-14-2017, 09:17 AM
#15
Could this be the issue I had this past week? I rented a dual axle TT from the base, and the brakes would only work occasionally, and I couldn't get the wheels to lock up at all with the manual control, even with the gain all the way up.
It would work occasionally on the road, especially if I applied the brakes slowly and lightly.
Occasionally it would pulse the brakes as I was slowing.
Other times I would get a fault or no brakes.
I was going to give the Outdoor Rec folks some hell on Monday when I return it, glad I ran into this.
It would work occasionally on the road, especially if I applied the brakes slowly and lightly.
Occasionally it would pulse the brakes as I was slowing.
Other times I would get a fault or no brakes.
I was going to give the Outdoor Rec folks some hell on Monday when I return it, glad I ran into this.
Another possible cause for poor brake detection/operation is the 7-pin connector itself. It is a very poor design with a pigtail that goes between the main wiring harness and the back of the 7-pin connector. Even now that they have flipped the orientation moisture still gets in and results in false trailer disconnects or lack of trailer detection. I've found if I dry it as best as I can and use a contact lubricant that displaces moisture I will be good for a couple to few months. In a pinch I've just dried and reseated the connector a few times to get home.
Edit:
Forgot to mention this is the connection on the backside of the 7-pin connector itself.
Edit:
Forgot to mention this is the connection on the backside of the 7-pin connector itself.
07-14-2017, 05:27 AM
#16
Senior Member
I had searched for a braking controller thread and found another, then someone posted this thread link on that thread. I also have a 2015 that I could not get my 18' flat bed trailer to lock the brakes. Then figured out reading the other thread that its the Ford program that won't allow it to lock up like my 2010 or my 2004 or any of the other 7 Ford trucks I've owned.
The engineers are great for driving trains. Not keeping us safe from ourselfs.
The engineers are great for driving trains. Not keeping us safe from ourselfs.
07-17-2017, 08:57 AM
#17
Senior Member
I had searched for a braking controller thread and found another, then someone posted this thread link on that thread. I also have a 2015 that I could not get my 18' flat bed trailer to lock the brakes. Then figured out reading the other thread that its the Ford program that won't allow it to lock up like my 2010 or my 2004 or any of the other 7 Ford trucks I've owned.
01-15-2018, 09:43 AM
#18
Still happening with 2018 models
I have a new 2018 expedition that's never had a trailer connected yet, and I get the same trailer disconnect messages when it snows. I looked in the 4 and 7 wire recepticals and they look obviously unused with diaelectric grease in them. I'm wondering if there's an issue still with the wiring harness being defective.
