Emergency Breakaway switch Brake Activation

[jstadler]

2017 Montana 3820 FK Legacy model Brake issue

Hi I had my wheels off the ground and was checking things over. I pulled the breakaway for emergency breaking and nothing happened. There is power to the breakaway switch, (12 volts DC) but I can’t tell anything else.

Is there a controller for the management (if so where is it) of the emergency breakaway or is power just sent to the bakes if the switch is activated? I need help troubleshooting this.

Thanks

John

[BB_TX]

How did you determine nothing happened? Every year I would jack one wheel at a time just off the ground, pull the break away pin, and try to spin that wheel. In less than 1/4 turn that wheel would lock up. Put pin back in, lower that wheel, and try the next one.

There is no separate controller. Wired direct to battery.

[mhs4771]

You say you had 12V at the switch, was that at both contacts?

[jstadler]

Originally Posted by BB_TX

How did you determine nothing happened? Every year I would jack one wheel at a time just off the ground, pull the break away pin, and try to spin that wheel. In less than 1/4 turn that wheel would lock up. Put pin back in, lower that wheel, and try the next one.

There is no separate controller. Wired direct to battery.

Thanks that is what I did and no go there is DC on both leads of the breakaway switch so I'll have to trace wires. I did try this while it was connected to the truck and shore power would that make a difference?

[jstadler]

Thanks that is what I did and no go there is DC on both leads of the breakaway switch so I'll have to trace wires. I did try this while it was connected to the truck and shore power would that make a difference?

[Rotnjonny]

In my 2022 with Legacy package, I have disc brakes. The breakaway functions the same, 12DC coming in one side and when you pull the pin, you should have 12DC coming out the other side of the breakway box. The difference is that the 12DC is going back to the disc brake actuator. Which is activating the disc brakes on all wheels. When you pull the pi, you Cana hear the actuator engaging the disc brakes

[jstadler]

Thanks I have 12V DC on both sides of the switch, I'll have to trace that back to see if it's getting to the wheels. I did have the wheels off the ground pulled the pin and nothing, I had the truck connected actuated the brake and gain control knob on a F350 worked as I expected. Something must be disconnected and not sending power back to the brakes. Thanks

[BB_TX]

If it worked thru the truck but not thru the break away switch I would open the electrical junction box on the pin box and make sure the wire from the breakaway switch is connected. It may have come loose.

[rohrmann]

The breakaway switch bypasses any truck connection and of course there is no shore power in a situation where you have a trailer become disconnected while on the road. When the breakaway switch is activated, the battery is directly connected to the brakes, unless there is an open connection between the breakaway switch and the brakes.

[jstadler]

Great advice thanks turns out the cord for the truck was pulled out by the dealer when I purchased it, perhaps the connections are not right or not properly connected. Thanks

[ChuckS]

When testing the emergency brake away switch the truck to RV 7 way plug should be Removed.. doing so prevent possible feedback from the RV battery to the trucks trailer brake control and damage to the trucks trailer brake control

When you pull that brake away pin you are applying direct RV battery power to the wire harness for all four electric brakes.

This is a simple parallel circuit for the brake wiring and with a multimeter you should be able to quickly find the issue ..

A video I put together that may help you with your troubleshooting

https://youtu.be/kpO2KgtzXkE?si=AkYPCXuV8TSTXBhM

[jstadler]

Thank you very much! I hope I did not damage my brake control on the truck it did work when the breakaway was pulled out so I think I am good. John

[jstadler]

HI you are awsom. I have brakes to the trailer from the truck but not as good as it was before I had someone pack the brakes. The pigtail was pulled out by the dealer for the junction box not sure they knew which wire whent were. So I think I have one of two issues, wire not connected to the right wire in the juntion box for the breakaway switch (what color wire on the trailer should the breakaway connect to? Or the tech did not know what wire to connect the breakaway wire to. I do get 12 volts to the breakaway both site but no brake action. Do you think I am on the right track? I just dont know wheh wire on the trailer the bllue breakaway wire should attach to thanks so much for your help;

[ChuckS]

This info may be helpful for you.. something I put together a while back

[jstadler]

Well thanks everyone for all your help. I discovered that my breakaway swith was on all the time and therefor I think my magnets are shot. I don't know if there is a fuse in the like to the braks i.e. blue wire if not then I supect the magnets are burned out. What is odd I still get 1.2 ohms of resitance when measured at the hitch cable but I never see any power that I can measure at the wheels themselves. i'll have to take it in and have someone more advanced then me fix the system... Bummer

[BB_TX]

If you have 12 volts on both sides of the breakaway switch but no 12 volts at the brakes themselves then you have a wiring problem somewhere. Assuming the wiring is done in the standard wiring colors, there should be a blue wire from the 7 pin cord to the junction box. In the junction box that blue wire should connect to another blue wire that goes back to the brakes. At that same connection point, there should be a wire from the breakaway switch connected to those two blue wires so that either the truck or the breakaway switch can actuate the brakes thru the same wire to the axles. So you should have 12 volts at that 3 wire connection if the breakaway switch is actuated.

If you do, then you should find that blue wire going to the a connection point at your first axle and your first set of brakes. If you had 12 volts back in the junction box then you should have 12 volts at that axle. If not, you have a break in the wiring between those two points.

At that axle connection point there should be a wire to both of those brakes and another wire to the second axle with wires then to each brake. And you should have 12 volts at that second axle also.

If you have 12 volts in the junction box but not at the axles I would not worry about the brakes themselves until you solve the 12 volt issue.

[jstadler]

Thanks Bill then if I undestand you right there is one blue wire from the truck and one blue wire that goes to the trailer they should be connected together with one lead of the breakaway switch? I think you are on to something that is not how it's wired today.

Thanks

[BB_TX]

This pic shows it well.

[jstadler]

You are so right the blue wires are not connected getting a new pigtail this one is woren will rewire next weekend.

Thanks for your help!

John