Recurring Short in Brakes - Troubleshooting Help

[K_M_H]

It's been a while, but we're back and trying to get ready for camping season finally. I've got a break in the weather in Southeastern PA (finally) and I'd like to take some time to look at why our brakes have an intermittent short. I'm 99% sure that somewhere, somehow there's slack wire that rubs. I had one of the brakes fixed, but the shop by us is about $400 apiece to fix them and the wires are considered a "wearable part" under the warranty. We've got a 2022 Wildwood X-Lite 273QBXL with tandem Lippert Axles. I didn't get a good photo of the Axle Serial number the last time I was over at the storage yard, but I will try again the next time I go over. I'm alright with electric in and of itself, but the brakes are a bit difficult for me to diagnose. I can't seem to find the worn point in the wiring that's causing the problem. Any help would be appreciated - especially if you have ideas to keep it from recurring.

Thanks!

 

[D W]

Define "intermittent short" " ?

Here is a Lippert Axle Manual to help you out:

 

[K_M_H]

First, thanks for the manual, that will help with some of the debugging process.

To define "Intermittent Short" - I'm going by the built in Nissan Brake Controller (Tekonsha Prodigy P2) showing the "SH" Error code (Short) from time to time when braking, but not all the time.

I'm 99% sure that the insulation is rubbed somewhere that it doesn't maintain contact with a ground all the time. It may come down to inspecting the wires and locating the damaged section.

 

[TitanMike]

A good starting point might be the 7-pin receptacle on tow vehicle and plug on connecting cable. Especially if the receptacle or plug has screw terminals. Next would be junction box where the umbilical cable joins the trailer wiring.

From there it's a matter of following the brake wires. Sometimes the wires were routed through hollow tube axles and it was common for them to wear through where they entered and exited the axle.

BTW. Make sure the wiring AT the controller is not causing a problem. My old Prodigy P3 had a loose plug/socket on the back that cause intermittent error messages.

 

[davidgle]

I had a 2013 Sabre 5th wheel. The intermittent brakes drove me up a wall. My son in law finally identified my problem and fixed it. If your brake wiring is fed thru the axle tube, you may need to pull it out and use plastic ties to attach it to the outside of the axle tube. this fixed my problem but not until I had purchased a new controller and spent much time & $'s at the repair shop.

 

[Aussieguy]

Before buying anything though check:
7 pin plug AND cord for any corrosion or damage on the vehicle and an the trailer side
it's the easiest place to damage and the connectors (pins) may be corroded and loose connection

Then look at junction box where the 7 pin wiring joins the trailer wiring... may be a loose connection

You can use a multimeter to check continuity
I have a long length of wire with alligator clamps

clamp the the extension wire to the 7 pin brake wire... the other end of the extension is then clamped to one of the multimeter probes

then GO to the individual brakes and read with multi meter if there is continuity (OHMS)



if you suspect bad insulation ... easiest solution is to rewire the brakes
you can simply run the wire along the frame
OUT side of the underbelly
Use good quality wire + splices + marine grade heat shrink

 

[CedarCreekWoody]

Check your 7 pin connector plug (the umbilical cord.) The contacts should squeeze the connector pins on your truck. Sometimes these get sprung and are a loose fit. Use a small flat blade screwdriver and bend them back or replace the umbilical cord.

 

[Larry-NC]

What you really need...

What you REALLY need is an alert right where you are working, that only flashes when the short occurs. Here is how you make one:

• Get a socket for a "BA15" lamp with two leads, like this one.
• Get a tow-vehicle connector like this one.
• Get an 1141 or 1156 lamp bulb like this one.
• Get two 10' pieces of stranded wire, AWG 16 or 18 like this one.
• Connect one end of each wire to the lamp socket leads.
• Connect the other end of one wire to pin 4 (12v charging) on the tow-vehicle connector.
• Connect the other end of the other wire to pin 2 (trailer brakes).
• Disconnect the trailer from your tow vehicle.
• Plug this special connector with the lamp attached onto your trailer cable.

This effectively connects 12 volts from the trailer battery to the brakes THROUGH the 1141 lamp. This low current (limited by the lamp) won't apply the brakes hard, so it can be run for an extended time. The lamp may glow dimly.

But when the short occurs and the cable is grounded, two things happen:

1. No power is applied to the brakes.
2. Full 12 volts is applied to the lamp and it will shine brightly.

So plug this tester in and

• Wiggle the trailer cable at the plug end and watch for a flash.
• Wiggle the trailer cable at the junction box end and watch for a flash.
• Wiggle the cables going to the wheels at various points and watch for a flash.

This is why you need the 10 foot wires: so you could bring the lamp near where you are wiggling the cable.

 

[Bob K4TAX]

Larry, "Larry-NC", has an excellent troubleshooting method.

Bob