Trailer Brakes Not Working

[Matt Jackson]

Ok guys, really hoping for some help on this one.

I have read many trailer brake posts but have not had any luck getting mine to work.

I have a 2014 dodge ram 1500 Slt quad cab. It is however electrically 98% 2020 tradesman. I can go more in to that if needed but don’t want to bore everyone.

The 2020 (tradesman) had no trailer brake controls from factory, I purchased a kit from dodge using the 2020 vin and installed it.
Proceeded to use alfaobd to turn on the 6 options relating to the trailer brake but the trailer brakes do not function. Everything else works fine.
Worth mentioning I have changed out the original 8.4 uconnect to a uconnect 8.4 5 so it has wireless apple carplay, I did this with the infotainment harness. I can see the trailer option in the menu after adding it with alfaobd.

The physical plug that the trailer plugs into at the rear of the truck is original 2014 but everything else is 2020, can’t see this being different between the years as the orientation of the pins are the same.

Trailer brakes functions fine on a buddy’s truck so no trailer issue.

With no trailer plugged in I thought something popped up on the dash when moving the brake slider or pressing the gain buttons but again nothing happens. Checked all the fuses with a tester and all good.

Does anyone have a wiring diagram that I could use to do continuity tests from the back of the truck to the controller wiring?

I used trailer brake control module 68288760AC

Trailer brake switch 68105206ac

I have confirmed that there are no pending fault codes on the engine side or the ABS module (both are 2020 tradesman)

I will attach some pics

 

[GTyankee]

Did they change things around in 2017/18
something about a security cable

 

[04fxdwgi]

That 68288760AC module is the one for a '16 to '24 model years. Mopar # 68092732AF is for the '13 to '14 model years.

I ran into the same problem, except in reverse, trying to get the '14 module to work in a '16. The correct module fixed it.

 

[2003F350]

That 68288760AC module is the one for a '16 to '24 model years. Mopar # 68092732AF is for the '13 to '14 model years.

I ran into the same problem, except in reverse, trying to get the '14 module to work in a '16. The correct module fixed it.

Normally I'd say you're correct, HOWEVER it sounds like he's put a LOT of wiring/computer from a '20 into this '14, so not sure if using the '14 module would fix this or not. It depends on what computer/wiring interactions he's got, and without knowing in detail what he's done it's going to be hard to say if this will fix it.

Though it may not hurt, OP, to try what he's suggesting - it may or may not fix your problem but it's relatively inexpensive.

 

[04fxdwgi]

Normally I'd say you're correct, HOWEVER it sounds like he's put a LOT of wiring/computer from a '20 into this '14, so not sure if using the '14 module would fix this or not. It depends on what computer/wiring interactions he's got, and without knowing in detail what he's done it's going to be hard to say if this will fix it.

Though it may not hurt, OP, to try what he's suggesting - it may or may not fix your problem but it's relatively inexpensive.

There lies the problem. So many variations to original system nearly demands a trial and error approach. One part that is not compliant will doom the whole endeavor and create a huge headache sorting out which part is the offender..

 

[Matt Jackson]

Thanks for the replies, everything electrically is from the 2020 tradesmen truck, every wiring harness, bcm, pcm abs module, engine, trans, transfer box, rf module and keys.

I did have functioning factory trailer brakes in the truck before I did the work and initially put the original TBM and switch back in it, however when they did not work I learned that the modules were different between the years, and the switch a different part number.
That’s when I went to dealer with the tradesmen vin and got the parts for that vin, still nothing.

Am I right in saying that something comes up on the dash when you push the gain buttons or slide, even with no trailer plugged in?

 

[turkeybird56]

Thanks for the replies, everything electrically is from the 2020 tradesmen truck, every wiring harness, bcm, pcm abs module, engine, trans, transfer box, rf module and keys.

I did have functioning factory trailer brakes in the truck before I did the work and initially put the original TBM and switch back in it, however when they did not work I learned that the modules were different between the years, and the switch a different part number.
That’s when I went to dealer with the tradesmen vin and got the parts for that vin, still nothing.

Am I right in saying that something comes up on the dash when you push the gain buttons or slide, even with no trailer plugged in?

YES will display even if no trailer plugged in, or let me clarify: Does this on my 2019 5th Gen RAM. Pics: With trailer adjustments engaged (gain slide/buttons) and display before reverts back to last display selected. (done using slide squeezed together to maximum output, and than released).

 

[Matt Jackson]

YES will display even if no trailer plugged in, or let me clarify: Does this on my 2019 5th Gen RAM. Pics: With trailer adjustments engaged (gain slide/buttons) and display before reverts back to last display selected. (done using slide squeezed together to maximum output, and than released).View attachment 542538View attachment 542539

Yeah I did think something came up when I had them working before doing all the work to the truck. Thanks!

 

[turkeybird56]

Fig

Yeah I did think something came up when I had them working before doing all the work to the truck. Thanks!

Figured 2 pics @ a pic worth 1,000 words U got 2,000 words, LOL. My inane sense of humor.

DA BOIRD.

 

[Matt Jackson]

Electrically all that’s original to the 2014 is

Fuel pump
Dash (gauges)
Airbags
Airbag module
Interior light in headlinining
Wiper motor
Windshield washer pump
Door lock motors
Window motors
Trailer plug that mounts in bumper
Tow haul button
Door switches accept drivers door
Radiator cooling fans

Maybe a couple of things I’m missing but I think that’s it.

 

[turkeybird56]

Electrically all that’s original to the 2014 is

Fuel pump
Dash (gauges)
Airbags
Airbag module
Interior light in headlinining
Wiper motor
Windshield washer pump
Door lock motors
Window motors
Trailer plug that mounts in bumper
Tow haul button
Door switches accept drivers door
Radiator cooling fans

Maybe a couple of things I’m missing but I think that’s it.

Something connected/not connected maybe wrong module, who knows not talking to other modules to enable/display. Electronic troubleshooting on these rolling computers is a PITA (even more so on 5th Gen changes). And since U pulled stuff outta a 20 and put into a 14, OMG, U must be pretty handy. The above thought ref different modules may help, BUT U R way outta my knowledge level. Sorry, no better help than a few pics.

Good Luck.

 

[Matt Jackson]

I’m thinking it could be a module issue as well. I went to a wrecking yard before the dealer to see if I could find the module they suggested for a 2020 and there seemed to be a different module in every truck I found one in, not sure on the year of each truck I looked at though and neither did they.

If it was the plug at the back I should still be getting something on the dash when I move/press the buttons.

It’s my understanding that the TBM talks mainly to the abs module.

Does anyone know the pin out on the connectors to the TBM?

Is there anyone with a 2020 gen 4 with trailer brakes that could confirm which part number is on their module?

 

[04fxdwgi]

As I stated before, 68288760ac is for the '16 to '24 models. It replaces 68288760AA, 68288760AB, 68371679AA

2016-2024 Ram Trailer Tow Module 68288760AC | My Mopar Parts

2016-2024 Ram part # 68288760AC - Trailer Tow Module

www.mymoparparts.com

Also, some have reported that the plugs on the module can fool you into thinking they are latched, when they are not.

You state that the Dash is '14. Does everything else work in it? I believe I recall that the CANbus protocol had changed slightly in the Gen 4's at one point, making the comms incomparable between early vs later years of Gen4's.

 

[Matt Jackson]

As I stated before, 68288760ac is for the '16 to '24 models. It replaces 68288760AA, 68288760AB, 68371679AA

2016-2024 Ram Trailer Tow Module 68288760AC | My Mopar Parts

2016-2024 Ram part # 68288760AC - Trailer Tow Module

www.mymoparparts.com

Also, some have reported that the plugs on the module can fool you into thinking they are latched, when they are not.

You state that the Dash is '14. Does everything else work in it? I believe I recall that the CANbus protocol had changed slightly in the Gen 4's at one point, making the comms incomparable between early vs later years of Gen4's.

Thanks for the reply!

Yep the whole canbus system and wiring in the truck is now 2020 so that module is within the range of the electrical components. It’s only really the body of the truck and chassis that is 2014 along with a few other bits inside the truck.

I did see that post about the plugs not connecting properly so I have triple checked those.

 

[62Blazer]

Even without a wiring diagram you could start probing wires. I would start at the trailer brake module in the dash. Verify you are actually getting power to it. At least one pin should have power to it (would guess 12 volts). Should also have a ground.

Then you should also be able to see some signal coming out of it when you push the brakes on the truck. Check each pin with the brakes released and then pushed and see which one lights up.

 

[Matt Jackson]

Even without a wiring diagram you could start probing wires. I would start at the trailer brake module in the dash. Verify you are actually getting power to it. At least one pin should have power to it (would guess 12 volts). Should also have a ground.

Then you should also be able to see some signal coming out of it when you push the brakes on the truck. Check each pin with the brakes released and then pushed and see which one lights up.

Thanks for the reply.

Yes that was one of the first things I did when I installed the module the dealer told was for the 2020 vin. With the truck running I had the following.

4 pin connector

-14v on red
-Confirmed ground on the black.
-nothing on remaining 2.

10 pin connector

-2v on yellow
-3v on orange (could be red but looks orangey to me)
-nothing on the remaining 8 neither a confirmed ground.

A pin out would be helpful to see if there is meant to be a ground on the 10 pin. No solid black in it though so would assume not…. But you know what they say assumptions

I will attach some pics for reference.

 

[Matt Jackson]

Thanks for the reply.

Yes that was one of the first things I did when I installed the module the dealer told was for the 2020 vin. With the truck running I had the following.

4 pin connector

-14v on red
-Confirmed ground on the black.
-nothing on remaining 2.

10 pin connector

-2v on yellow
-3v on orange (could be red but looks orangey to me)
-nothing on the remaining 8 neither a confirmed ground.

A pin out would be helpful to see if there is meant to be a ground on the 10 pin. No solid black in it though so would assume not…. But you know what they say assumptions

I will attach some pics for reference.

Didn’t try with brake pedal pressed so will update shortly.

 

[Matt Jackson]

Didn’t try with brake pedal pressed so will update shortly.

With the brake pedal pressed with the engine running there was no change on the 10 pin plug but on the 4 pin the green/white got 14v. Odd the way no change on the 10pin with the brake pedal pressed isn’t it? Maybe that’s more from the abs module and other modules when the truck is in drive and in motion?

 

[62Blazer]

Yep, sounds like you are at the point now that a wiring diagram is needed. You might call the local dealership and often they will print you out a few pages from the service manual. I'm guessing there is some type of flow diagram in there that explains the series of events that should happen. I would also expect some sort of variable voltage output based on the gain settings of the controller (how hard they apply the brakes) and it should also be variable based on inertia (the harder you hit the truck brakes, the more power to the trailer brakes).
Not familiar with the factory brake controller and what the 10 pin connector is all about. Most aftermarket brake controllers only have 4 pins connected to the truck...guessing that is what the 4 pin is on your setup:

Battery Voltage power to the controller (which you have)
Ground wire (which you have)
Brake light signal (would suspect this is the battery voltage you get on the green/white when hitting the pedal.....also, if you hit the manual slide button on the brake controller it also triggers the trailer brake lights)
Brake controller signal (this would be the variable voltage going to the trailer brakes)

 

[04fxdwgi]

I have the '13 to '16 ram service manual in PDF, but is probably not what you need, as you converted to '20 wiring.


Have you checked all these fuses?

F53 ATR 20 amp Left Trailer lights
F81 ATR 20 amp Right Trailer lights
F29 FMM 20 amp Trailer Park lights
F28 FMM 20 amp Trailer Back up lights
F30 FMM 30 amp Direct from battery

F11 J Case 30 amp Brake Lever
F87 ATR 10 amp ITBM module