No Brakes!

Robertsmusings · 03-19-2023, 03:08 PM

Brakes in our TT worked well from Tucson to Why, AZ. Even for a panic stop.

3 days later, after hitching up, tested the brakes on leaving camp and nothing. I tested the umbilical cable conductivity and visually inspected the wires to each wheel. No anomalies noted.

With DW squeezing the brake controller paddles my VOM could not detect a signal at the umbilical junction box.

Changed settings on the built-in brake controller this morning and retested. I could feel a VERY slight tug at 10 mph on squeezing the paddles and then a release.

Do I take it to Ford or to a trailer shop? TV is a 2020 F-150.

TitanMike · 03-19-2023, 03:21 PM

Quote:

Originally Posted by Robertsmusings

Brakes in our TT worked well from Tucson to Why, AZ. Even for a panic stop.

3 days later, after hitching up, tested the brakes on leaving camp and nothing. I tested the umbilical cable conductivity and visually inspected the wires to each wheel. No anomalies noted.

With DW squeezing the brake controller paddles my VOM could not detect a signal at the umbilical junction box.

Changed settings on the built-in brake controller this morning and retested. I could feel a VERY slight tug at 10 mph on squeezing the paddles and then a release.

Do I take it to Ford or to a trailer shop? TV is a 2020 F-150.

First thing I'd check would be the contacts both in plug and socket where Umbilical Cord is plugged in.

A quick check of the "trailer side" is to unplug Umbilical cord from truck, pull the breakaway switch cable/plug so trailer brakes are fully energized, and now try to pull the trailer. Should be either impossible or darn difficult. If not on dry pavement the wheels will most likely be locked up if all is OK.

If brakes activate fully then the problem is either in Umbilical cord, connector, or controller. Messing with those will be limited to your skills or desire.

Robertsmusings · 03-19-2023, 04:45 PM

I did check and clean the contacts.

Thanks for suggesting pulling the breakaway pin. I'll try that next.

Reverse_snowbird · 03-19-2023, 05:12 PM

The battery on your trailer is fully charged?

Robertsmusings · 03-19-2023, 05:33 PM

Yes.

Robertsmusings · 03-19-2023, 06:17 PM

With the breakaway pin pulled, the tires rotated easily.

I will be looking for a competent trailer shop in Buckeye, AZ tomorrow.

Thank you

cbty · 03-19-2023, 06:18 PM

I made a tester with an old blower motor and a 7 way round connector. Using only the trailer brake control and ground. It is a great way to visually show someone the vehicle is working.

Mike134 · 03-19-2023, 07:52 PM

when I lost my brakes completely like you did including the break away it was a cheap crimp connector that visually looked good had failed on the heavy blue brake wire under the trailer

TitanMike · 03-19-2023, 08:38 PM

Quote:

Originally Posted by Robertsmusings

With the breakaway pin pulled, the tires rotated easily.

I will be looking for a competent trailer shop in Buckeye, AZ tomorrow.

Thank you

If all wheels turned freely the problem is just in the connection to battery, breakaway switch, or wire from breakaway switch to first connector where brake power branches to each side.

sonofabeacher · 03-20-2023, 07:00 PM

Quote:

Originally Posted by Robertsmusings

Brakes in our TT worked well from Tucson to Why, AZ. Even for a panic stop.

3 days later, after hitching up, tested the brakes on leaving camp and nothing. I tested the umbilical cable conductivity and visually inspected the wires to each wheel. No anomalies noted.

With DW squeezing the brake controller paddles my VOM could not detect a signal at the umbilical junction box.

Changed settings on the built-in brake controller this morning and retested. I could feel a VERY slight tug at 10 mph on squeezing the paddles and then a release.

Do I take it to Ford or to a trailer shop? TV is a 2020 F-150.

Check your owners manual for your tow vehicle. There could be a fuse for trailer/tow brakes. I don't know if Ford has one but I do know Chevy does. It could be under the hood.

Travelers2k · 03-23-2023, 06:45 AM

We had total brake failure because the brake lines were not mounted securely on the axle. Forest river said they should have been tied down with just plastic zip ties. How ridiculous is that. The hydraulic brake lines are metal and they just flop around, eventually causing a snap. Forest River of course doesn't want to pay for repairs. Accident waiting to happen.

curtiscapk · 03-23-2023, 08:34 AM

Quote:

Originally Posted by sonofabeacher

Check your owners manual for your tow vehicle. There could be a fuse for trailer/tow brakes. I don't know if Ford has one but I do know Chevy does. It could be under the hood.

#4 fuse passenger fuse block

https://www.startmycar.com/us/ford/f...o/fusebox/2020

Love this site!

**Mr. Dan** · 03-23-2023, 08:38 AM

Quote:

Originally Posted by Travelers2k

We had total brake failure because the brake lines were not mounted securely on the axle. Forest river said they should have been tied down with just plastic zip ties. How ridiculous is that. The hydraulic brake lines are metal and they just flop around, eventually causing a snap. Forest River of course doesn't want to pay for repairs. Accident waiting to happen.

None of my travel trailers/5th wheels have had hydraulic brakes/lines. Mine have all had electric brakes so just wires.

5picker · 03-23-2023, 10:52 AM

Quote:

Originally Posted by Travelers2k

We had total brake failure because the brake lines were not mounted securely on the axle. Forest river said they should have been tied down with just plastic zip ties. How ridiculous is that. The hydraulic brake lines are metal and they just flop around, eventually causing a snap. Forest River of course doesn't want to pay for repairs. Accident waiting to happen.

What kind of R/V do you have?

Hydraulic brakes with metal lines are rare from the factory on towables.
I see it was your 1st post and you don't have any information in your profile or a signature line.

gw1800 · 03-27-2023, 07:31 PM

Quote:

Originally Posted by Reverse_snowbird

The battery on your trailer is fully charged?

The battery in the trailer has nothing to do with the brakes when hooked up to the truck. It only control the brakes when the breakaway switch is pulled.
No brake power at the junction box on the trailer is either a bad cord, trailer plug or blown fuse in the truck if it has built in trailer brakes. It is possible the cord went bad if plug was pulled by the cord and not the housing.

Robertsmusings · 03-28-2023, 02:43 PM

I retested voltages at the umbilical cable junction box.

Truck disconnected, on shore power, break away cable pin pulled:
Battery: 12.8v
Blue Brake wire: 12.25v
The difference here might be attributed to using frame ground vs battery lug.

Truck connected, on shore power, break away cable pin inserted:
Brake wire: 9.5v
Brake controller is set to maximum.

The voltage at the brake wire zeros when the controller paddles are released and the pin is inserted.

What should the brake controller voltage be? Where should I look next?

Since my prior post we had a different mechanic adjust the trailer brakes so they are tighter.

gw1800 · 03-28-2023, 03:10 PM

Why are you checking while connected to shore power and truck connected? There should be no power on the brake wire while only on shore power.

Robertsmusings · 03-28-2023, 03:47 PM

When the truck is connected to the trailer, the TT and TV batteries are paralleled via the V+ and V- pins. Staying on shore power keeps the TT converter also paralleled keeping the batteries voltage constant.

gw1800 · 03-28-2023, 04:13 PM

Quote:

Originally Posted by Robertsmusings

When the truck is connected to the trailer, the TT and TV batteries are paralleled via the V+ and V- pins. Staying on shore power keeps the TT converter also paralleled keeping the batteries voltage constant.

Battery power yes. Brake power should be not be aqffected. Sounds a though there is something in the trucks controller drawing down the voltage while connected.

The truck should be isolated from the TT power when the key is off so in fact the batteries are not in parallel. That stops the trailer from draining the trucks batteries.

Maybe it's me, but I always pull the trailer plug before hooking up shore power. Too many electronics involved in the truck and trailer.

Robertsmusings · 03-28-2023, 04:37 PM

Normally I do pull the umbilical cable before connecting shore power and only plug it back in after disconnecting.

To test the brake controller the truck requires being in the on position. Parrelling assured me of full power.

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