Low Trailer Braking Power [Resolved!]
 

Background:
For the end of the last towing season (2018), I had a low braking power (on Trailer). Moving the manual trailer brake controller (hard) would no longer lock up the brakes.., even on gravel going 5mph!. To trouble-shoot further, I tested the voltage at each trailer wheel (6 wheel in my circumstance). All wires seemed ok and connected to the magnet(s), voltage readings were not even half power (6v) with hard pedal depress. So we hooked up my prior Denali, and she locked up the trailer wheels with no problems.

Dealer visit time!:
I've got a great (listening) dealer and technician relationship. My tech quickly whipped out this tester and I wasn't even lighting up 1/2 of those blue arched lights (on the top display). He quickly went to the cab and noticed the trailer braking dash control-display was already in "High" mode and set to the top of the 10 scale....

https://cimg4.ibsrv.net/gimg/www.for...438efc50bd.jpg
I also personally purchased one of these brake load testers^ as well. I searched high and low incl Fleabay, $126.44 Free Shipping here

Dealer was puzzled so they gave me a loaner and sent me home for the day. The next day they removed and replaced the built-in brake controller, only to find no (difference) or fault with the original one, Tech next went on to examine wires and connections. Being mine is garage kept and not driven in the winter, the undercarriage is clean as the top side, so he was reluctant and saved this for last as he mentioned normally it would be first. Well, it turned out to be the wrong call doing the dash controller first.

Conclusion:
My under bumper 7 pin trailer connector was shorting out (not totally however) on the pin 7. Even though I use the truck bed connector for my trailering, it's still spliced into each other so it has the same (partial short) effect on either plug. There is a Ford - TSB 18-2106 on this connector/receptacle w getting moisture in it and corroding, losing connection and causing the "Trailer not connected" notice, but clearly it can effect other things like brake power to your trailer as well. I never once had the trailer not connected notice btw, and, as soon as I disconnected the coach, it would sense it right away. So anybody with a possible low trailer braking issue you might try this first!

Hope this helps others!
Happy RVing guys :)
KJ & Debbie
YouTube.com/WhereTWOnext?

Wow, thanks for posting. I sure would be concerned with that little brake on the rig you have. Good job getting to the bottom of it.

Glad to hear this was resolved. I put dielectric grease in all my connectors, hoping to prevent problems like this. Like you, mine is garage kept and not driven much in the winter.

They installed a new connector/receptacle but only on the bumper end, the bed receptacle is still the same as he said he could not find any resistance in that plug.or line.

My first in-depth pull will be the end of April to the Smokey Mtns.

It seems strange that the brakes worked fine on your old trailer but not on the new one if a short was causing the problem?
Gary

Old trailer? I've never tested this Ford with my "old trailer".

I think you are mixed up with the testing with my old (Denali) truck which was as said did lock up the brakes.

So only one trailer and as mentioned in the first posting; on the end of the last RV season. Same truck and trailer that's in my signature below...

Yes I misread what you had said. Sorry about that.
Gary

This is getting crazy with all of the different exterior plugs on these trucks corroding. Why is this happening at all? My concern is 5-10 years down the road. I don't want to get stuck replacing wiring harnesses, being on long trips and trailer brakes aren't working, interior electronics acting wacky, etc. There really isnt a fix for poor quality of parts and bad designs.

Good info here. I have the same issue and will ask the dealer to order me a replacement plug. If they won't, it's only a $25 item so I'll just do it myself. Not worth the fight but they are usually pretty good when I diagnose things myself. I always thought it was the way of things with my 2017 vs. my previous 2012 when towing the XLR. However, it became more noticeable when towing my other two trailers. I can tow them with either my SD or the wife's SUV. My truck can barely lock the brakes on either but the Grand Cherokee has to be turned way down to avoid it.

Notwithstanding the trailer connector issue, I was concerned that I couldn't lock up the brakes on my 29' Jayco with the manual slider, even though the trailer seemed to stop fine. Anyways.....while doing wheel bearing maintenance, I did a brake adjustment per the Dexter axle instructions....whoa....what a difference! Brake controller gain is down around 3 from 7 and 8 and the manual slider will now flat spot the tires FWIW

Good tip!
My RV dealer did this back in the Fall of '18 upon my initial complaint. At this troubleshooting time, we were blaming the trailer. So this adjustment may of helped, but with the voltage getting robbed, it might not of been as noticeable as your adjustment did.... but!, I did report to the dealer that it seemed better but it wasn't near enough. Here's a video of what you're talking about...