5th wheel brake wiring

[tomthyme]

Hello Folks,
We have been wrangling with brake power issues on our 5th wheel for a while now. Most recently, I had an RV service company replace the 7 way pig tail running from the 5th wheel to the bed of my truck. This worked great for 4.5 hours of a 5 hour drive.

After we got back home, I set out to find the problem. I first raised the coach and went to test the breakaway switch, which I have done before. Sadly, the breakaway pin snapped off with 1/2 of it inside the switch mechanism. Ho hum. I then replaced the breakaway switch and confirmed it worked. However, my brakes still didn't work when applying the manual brake controller or pressing on the brake pedal in the truck.

I suspected a connection was bad on the pigtail as that was the most recent change. So, I started with the butt connector installed by the RV tech that mated the pigtail to the 5th wheel.

I noticed that there was a blue power wire from the truck running to the 5th wheel. Good! So I removed the butt connector and soldered the connection. At this same connection point, there was a blue power wire coming from the breakaway switch and teed off of this truck -> RV power wire. I wasn't sure why it was there, but I soldered it on, making a 3 way connection.

I spun the rig tires and hopped in my truck to operate the manual brake controller. Success! The brakes locked up! So, it's all fixed, right?

I lowered the rig, connected it to the hitch, and moved it forward and aft. Using the manual brake controller, the stopping power seemed to diminish after a few uses.

I will raise the rig again and spin the tires manually, then test the controller again, but I'm confused as to why the power would seem to diminish.

A test drive is obviously next to check the inertia braking capacity.

I know the wires at the axles have patches in them too. Now that I am a solder king, I plan to solder (and head shrink) those connections as well to be sure good connections all around.

Should I be thinking of something else? Any other tests I should be running?

Thanks for reading this long post and responding with some ideas.

Travel safely folks!

Tom

[Old-Biscuit]

First..
Need to confirm that the wiring AT each wheel to brake magnets are clean/tight

Secondly..
Adjust each wheel's brakes (when were they last inspected/brake shoes replaced)

Thirdly...
With truck disconnected..pull Emergency Break Away Pin and confirm FULL trailer battery voltage at Each Wheel position

Fourthly....
Confirm truck 7 pin receptacle is getting FULL Voltage via 'brake controller manual lever'

Fifthly...
Confirm trailer plug 7 pin connections are clean/tight