OEM Brake Controller XLT install trouble
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Tuned
Joined: Sep 2016
Posts: 347
Likes: 12
OEM Brake Controller XLT install trouble
Hey guys, tried the search but never found a solution. I have a 2017 F-150 XLT that didn’t come with the factory brake controller.
I installed the OEM one without trouble since the harness was already there behind the pocket in its place. I’ve done the 2 FORScan changes and it shows the brake controller as well as all the trailer brake controller functions through the menus.
However, it will not show a trailer connected even after I’ve tried multiple trailers that work fine with my F-250. I can adjust the gain settings, but as I do, the menu shows “No trailer connected”. When I manually squeeze the brake controller, it says the same thing. The trailer lights work fine, it’s just the brake controller part. If I try to drive with the trailer, it applies full trailer brakes when braking regardless of controller setting unless I set the gain to zero. (Then it applies no brakes)
I’ve tried undoing and redoing the FORScan settings, but it doesn’t change. Any idea? Thanks in advance!
I installed the OEM one without trouble since the harness was already there behind the pocket in its place. I’ve done the 2 FORScan changes and it shows the brake controller as well as all the trailer brake controller functions through the menus.
However, it will not show a trailer connected even after I’ve tried multiple trailers that work fine with my F-250. I can adjust the gain settings, but as I do, the menu shows “No trailer connected”. When I manually squeeze the brake controller, it says the same thing. The trailer lights work fine, it’s just the brake controller part. If I try to drive with the trailer, it applies full trailer brakes when braking regardless of controller setting unless I set the gain to zero. (Then it applies no brakes)
I’ve tried undoing and redoing the FORScan settings, but it doesn’t change. Any idea? Thanks in advance!
Tuned
Joined: Jan 2015
Posts: 472
Likes: 153
From: Southeast Wisconsin
Start with checking for the fuses in the main panel for the controller. I also have a '17 XLT and mine was missing one or both fuses, I can't remember which ones specifically. The fuse sizes and positions can be verified in the owners manual. Then I had a short in the brand new trailer wiring which resulted in a blown trailer lighting fuse. If you have the correct fuses in the correct slots, then its time to look at the wiring, starting with the harness connectors up near the spare tire. These connectors are notorious for moisture getting in and causing all sorts of gremlins. Get some dielectric grease and waterproof all the connectors back there. There are 4 or 5 of them if I remember correctly. Once I did all this, I never had another problem.
Thread Starter
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Tuned
Joined: Sep 2016
Posts: 347
Likes: 12
Great reply, thank you. I did check that all the fuses were there, and they all seemed to be in place and not blown. It looks like it’s time to look over the connectors in the back.
Is there a way to trick the truck into believing there is a trailer connected by grounding certain pins in the connector, or do I have to actually have a trailer connected? I’ve seen a lot of discussions on the F250 forum regarding the fact it has a smart controller that will not send current back there unless it senses a certain amount of draw. Is the F150 the same in that respect? My HOA doesn’t allow trailers to be parked for extended periods, so all my trailers are stored at a storage facility. I have seen those test connectors on Amazon to check the lighting, but I don’t know if the truck will also sense a trailer connected with those.
Thanks again!
Is there a way to trick the truck into believing there is a trailer connected by grounding certain pins in the connector, or do I have to actually have a trailer connected? I’ve seen a lot of discussions on the F250 forum regarding the fact it has a smart controller that will not send current back there unless it senses a certain amount of draw. Is the F150 the same in that respect? My HOA doesn’t allow trailers to be parked for extended periods, so all my trailers are stored at a storage facility. I have seen those test connectors on Amazon to check the lighting, but I don’t know if the truck will also sense a trailer connected with those.
Thanks again!
Tuned
Joined: Jan 2015
Posts: 472
Likes: 153
From: Southeast Wisconsin
I believe you are correct that the 150's also have a smart controller that will not send current back there unless it senses a certain amount of draw. And the Super Duty forum is going to have many more threads on this subject than the 150 forum. Another point of concern for these trucks in these situations is the battery. If you are still running the original battery, maybe its not putting out enough voltage to satisfy the system. The consensus seems to be that OEM batteries are on the way out after 3 years and will give you nothing but grief.
I believe your issues will be either the battery and/or moisture in the connectors. Sometimes it bent pins on the trailer plug. Sounds silly, but it doesn't take much of a misalignment of pins to cause a failure. Rarely is it a wiring issue. Except for me. I happened to buy a brand new Sure-Trac trailer with pinched wires and it drove me insane until I took it back to the dealer I bought it from and he tore stuff apart until he found the problem.
EDIT: Are you absolutely sure you bought the correct part number controller? Only way to be sure is verifying the part number is compatible with your VIN. I have seen threads where the wrong part number controller was installed. Ford makes a few different part numbers. Not sure why or what the differences are, but they do. The other thing I read is that the engine and key should be OFF when connecting the trailer to the truck. Do the connection, then start the truck and see if that helps.
One other thing that just occurred to me...I have also heard that some of the newer trailers with all LED lighting don't provide enough current resistance for the truck to recognize that a trailer is even connected. My enclosed trailer is all LED and has too many "bulbs" to count, so I don't have any issues in that regard. My garden trailer has only 4 standard filament bulbs, and no problems there either. But I wonder what would happen if I changed those 4 bulbs to LED. Would my truck sense enough current for a BC to function? I don't know...
I believe your issues will be either the battery and/or moisture in the connectors. Sometimes it bent pins on the trailer plug. Sounds silly, but it doesn't take much of a misalignment of pins to cause a failure. Rarely is it a wiring issue. Except for me. I happened to buy a brand new Sure-Trac trailer with pinched wires and it drove me insane until I took it back to the dealer I bought it from and he tore stuff apart until he found the problem.
EDIT: Are you absolutely sure you bought the correct part number controller? Only way to be sure is verifying the part number is compatible with your VIN. I have seen threads where the wrong part number controller was installed. Ford makes a few different part numbers. Not sure why or what the differences are, but they do. The other thing I read is that the engine and key should be OFF when connecting the trailer to the truck. Do the connection, then start the truck and see if that helps.
One other thing that just occurred to me...I have also heard that some of the newer trailers with all LED lighting don't provide enough current resistance for the truck to recognize that a trailer is even connected. My enclosed trailer is all LED and has too many "bulbs" to count, so I don't have any issues in that regard. My garden trailer has only 4 standard filament bulbs, and no problems there either. But I wonder what would happen if I changed those 4 bulbs to LED. Would my truck sense enough current for a BC to function? I don't know...
Lead Driver
Joined: May 2015
Posts: 5,881
Likes: 359
From: Mts. S. of San Francisco
+1 to checking that you got the right TBC for your model year. There is a sticky at the top of the forum about the change in the TBC for the 2018 model year, so be sure you got the correct one for your truck.
Cross-Country
Joined: May 2019
Posts: 63
Likes: 2
From: BAY CITY, MI
I have a 2018 f150 xlt with the 2.7 Had the backup assist but no trailer brake controller.
I bought one and put it in, and had the dealer enable it.
Hooked up and it worked great.
3 months down the road i hook my trailer up again and the brakes are locked right up. unplug the harness from the truck and you can hear the brakes release.
Took to a trailer place and they thought the 7 way was bad. put a new one one and it was doing the same thing. They told me i have voltage coming back to the plug from somewhere and its turning the brakes on. Any one have this problem??
I have an appointment at the dealer friday, but i am thinking its going to be one of those "its in your trailer problem."
Dont mean to hijack the thread, just have not found any situation similar to this
I bought one and put it in, and had the dealer enable it.
Hooked up and it worked great.
3 months down the road i hook my trailer up again and the brakes are locked right up. unplug the harness from the truck and you can hear the brakes release.
Took to a trailer place and they thought the 7 way was bad. put a new one one and it was doing the same thing. They told me i have voltage coming back to the plug from somewhere and its turning the brakes on. Any one have this problem??
I have an appointment at the dealer friday, but i am thinking its going to be one of those "its in your trailer problem."
Dont mean to hijack the thread, just have not found any situation similar to this
Logistics Pro
Joined: Jan 2010
Posts: 4,100
Likes: 1,635
I have a 2018 f150 xlt with the 2.7 Had the backup assist but no trailer brake controller.
I bought one and put it in, and had the dealer enable it.
Hooked up and it worked great.
3 months down the road i hook my trailer up again and the brakes are locked right up. unplug the harness from the truck and you can hear the brakes release.
Took to a trailer place and they thought the 7 way was bad. put a new one one and it was doing the same thing. They told me i have voltage coming back to the plug from somewhere and its turning the brakes on. Any one have this problem??
I have an appointment at the dealer friday, but i am thinking its going to be one of those "its in your trailer problem."
Dont mean to hijack the thread, just have not found any situation similar to this
I bought one and put it in, and had the dealer enable it.
Hooked up and it worked great.
3 months down the road i hook my trailer up again and the brakes are locked right up. unplug the harness from the truck and you can hear the brakes release.
Took to a trailer place and they thought the 7 way was bad. put a new one one and it was doing the same thing. They told me i have voltage coming back to the plug from somewhere and its turning the brakes on. Any one have this problem??
I have an appointment at the dealer friday, but i am thinking its going to be one of those "its in your trailer problem."
Dont mean to hijack the thread, just have not found any situation similar to this
It is possible there is a problem with the brake controller, could be a wrong part number or just a bad unit. Wiring should all have been there, if you had to splice into any harnesses then there could be an issue there. Or you have a bad wire somewhere in the truck.
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Moderator
Joined: May 2005
Posts: 8,227
Likes: 1,243
From: San Antonio, TX
There was a part number change in 2018 for the brake controllers. Make sure you have the 2018 and up controller and not the 2015-2017 controller. You can't tell by looking at them.
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