Electric Brakes Not Working

[Huck]

I have a Tekonsha P3 Trailer Brake Controller 90195. It doesn't display any error with brakes. No matter what load I set, when I pull the lever to employ the trailer brakes, there is little to no braking. The controller is set to electric brakes.

Recently I replaced the hubs and bearings. I don't know if the problem existed before this.

I just attempted to adjust the brakes, but didn't accomplish anything. I couldn't see the adjustment. There does seem to be about the right amount of drag on each wheel.

Added Info:

The brake controller tests for these conditions and there are no messages displayed, so good there.

• Open Ground
• Overload
• Output Shorted
• Power Loss
• No Trailer Connection

There is a troubleshooting screen on the brake controller. Four things are tested and these are the results:

1. Battery: 12.4 v
2. Voltage supplied from stoplight switch with brake pedal depressed: 14.2 v
3. Avg voltage provided to the trailer brakes: When I press the brake pedal it goes to .87, then changes to .3 and then changes to 1.5
4. Current provided to the trailer brakes: 0.0

I wonder if the wheels have to be turning for the current to register?

Could the brakes being out of adjustment result in no trailer brakes?

Ideas?

[WDavidG]

Huck,
I recently had a similar problem and after checking various more complicated possibilities I discovered a bad connection at the electrical plug connecting trailer and TV. Although it looked good on visual inspection cleaning the contacts solved my problem.



Your problem could of course be something else, including out of adjustment brakes as you suggest, bad ground or other issues. But learn from my mistake and eliminate the simple first. There are series of tests you can do to check the circuit from controller to brakes to identify the problem point that the more electrically savvy can suggest to you.



Good luck - I know it's a frustrating distraction.

[John in Michigan]

Huck,

- If there is electrical continuity between the brake controller and the brakes, the Prodigy P3 will display the voltage output to the brakes. In the diagnostic screen, you can also check the amperage output to the brakes.

- If the Prodigy P3 is displaying positive voltage and amperage output to the brakes, but the brakes are not engaging then the brakes may need to be adjusted.

- The brake adjustment nut is accessed through a slot on the backside of the brake plate. Rotate the adjustment nut using a screw driver.

- Check whether the brakes are engaging sufficiently by jacking up the camper and turning each wheel while having someone press the brake pedal (or brake controller override) in the tow vehicle.

[Joe Romas]

Yes but first does the P3 indicate the brakes are connected? If no error is reported your problem is most likely just the adjustment. My Dexter brakes has two slots in each backing plate so make sure your on the correct slot. The proper way to adjust the brakes is to tighten them untill the hub is locked then loosen them untill there's a slight drag.
Also there is a tool called a "brake spoon" made for the job.
Go to a local auto parts store and ask for one.

[Huck]

Originally Posted by John in Michigan

Huck,
- The brake adjustment nut is accessed through a slot on the backside of the brake plate. Rotate the adjustment nut using a screw driver.

I tried that and I couldn't see the adjustment nut. It's hard to get behind the wheel. Parkliner has some bolts with points on them, I think maybe they attach the floor to the chassis, that are like daggers if the trailer was to slip.

- Check whether the brakes are engaging sufficiently by jacking up the camper and turning each wheel while having someone press the brake pedal (or brake controller override) in the tow vehicle.

What I did was set the load to 10 on the brake controller and then engaged the brakes using the lever and it had little if any effect.

I added info from brake controller tests to original post.

[Huck]

Originally Posted by Joe Romas

Yes but first does the P3 indicate the brakes are connected? If no error is reported your problem is most likely just the adjustment. My Dexter brakes has two slots in each backing plate so make sure your on the correct slot. The proper way to adjust the brakes is to tighten them untill the hub is locked then loosen them untill there's a slight drag.
Also there is a tool called a "brake spoon" made for the job.
Go to a local auto parts store and ask for one.

Brakes are connected and controller seems happy.

[mary and bob]

Our Casita has a slot in the brake drum face where the adjusting tool can be inserted to adjust the brakes. Also when I had the drums off to grease the bearings I made notes on which slot in the backing plate to use and which way was tighten and loosen the shoes. Did that for each side. Wrote it down because I knew I wouldn't remember next time.

[John in Michigan]

Huck,

Your updated first post certainly shows a problem. When you engage the brakes even when not moving, the voltage should be much higher. The Tekonsha owner's manual recommends initially setting the power to 6.0 with the engine running. With a single axle trailer, the amperage shown in the diagnostic menu should be at least 6 amps.

EDIT: However, if you are parked apparently the power shown will be low because the sensor inside the P3 will sense that the tow vehicle isn't moving (forgot about this ---- its been a while since I've done any testing). In this case, use manual override switch to achieve max braking power.

[Raz]

I adjust my brakes with the wheel off. It eliminates having to crawl under the trailer and makes things much easier to see. I find an adjusting tool works better than a screw driver. While you can buy one at any parts store for a couple bucks I made one from a piece of scrap bar stock. Don't forget to put the little plastic plug back in the hole when you're done.

As to your brake issue, I'm guessing you have a bad connection. I would clean and tighten all connections and see if that helps.

[Paul O.]

As suggested, I would do the mechanical adjustment first. since my Scamp has high ground clearance, I never thought of taking the wheel off - excellent idea.

Then check the electrical continuity of the brake coils.

After I bought my 2004 Scamp in 2013, only one wheel brake was reliable, the other not completely. It took me a long time to figure it out - the problem was the electromagnet coil was worn and was intermittently shorting to the drum.

I solved the problem by installing new self-adjusting brakes. (Self-adjusting is, actually, a misnomer. They do not self adjust in normal, towing operation, they get only adjusted by applying them while backing up.)

[floyd]

The drag on the brakes may just be the magnet. The shoes may still need adjustment.
Jack up the trailer until the wheel clears the ground, spin it adjust it until you can't spin it. Adjust it back until it spins with a bit of resistance.

[Raspy]

Electric brakes get weaker over time as they wear and get out of adjustment. They can also be weak when brand new, until they break-in, over time. I recently repacked my bearings and the brakes were noticeably weaker afterward, but got better with some use. So, they are temperamental.

Mine are self adjusting too, but that feature doesn't work on any of the four wheels. Backing up while applying them is the traditional way to get them to adjust, but if the adjuster nut is tight on it's threads, it doesn't work.

Finally, I was running my controller on setting 10 (max) and still not getting enough.

So, mid way through our recent trip I adjusted them with a conventional brake spoon and all is well. If you look into the adjuster hole with a flashlight, you'll see the adjuster nut. If you have self adjusting brakes, a little piece or metal is trying to work the ratchet teeth on the adjuster nut. You can see which way it is trying to turn the nut, and then you can turn the nut yourself, with the brake spoon, in that direction. It's tedious, but it definitely works. I adjusted mine twenty clicks tighter on the first wheel before it began to drag. Then I did twenty on each of the others just to keep them even and close, if not perfect. None got tight at that point, but were much closer to being right. A road test confirmed the system was working very well and I had to reduce the controller setting from 10 to 4 to keep them from locking. Even at 4, they are more aggressive than the TV brakes. Just where I like them.

My backing plates have two windows to reach the adjuster through. One can be where you point the light and look in, while the other is where the spoon goes in. Mine had no rubber plugs.

[floyd]

Raspy;
What brand or part number brakes do you have?
I have never seen self adjusters on electric brakes.
I would like to see how its done....


Never mind , I found them,
figgers... I have an appointment next week at Scamp to upgrade to a Zero Axle with 10" brakes.. prolly not self adjusting! shucks.
Oh well 5 minutes every couple of years aint much.
BTW the following video says that they adjust while underway, no mention of reverse. Still it could be...

https://www.youtube.com/watch?v=D1PaT3-QJ3s

[Raspy]

floyd,

Mine are the Dexter brand on the Oliver. I've been told that there is a system that self adjusts while going forward, but I have no idea how it works.

I had the drums off, but was so busy concentrating on the bearings that I didn't think about how the adjusters work, or if they are different than the traditional system that adjusts in reverse with application of the brakes. A little bit on each brake application.

Either way, they don't work. And that doesn't surprise me. The ratchet nut adjuster on self adjusting brakes has always been a place for failure with self adjusters. The threads get corroded or gummed up and they won't work.

I like electric brakes, but these haven't been as good as I had expected. Mine are the 3500 lb axles with 10" brakes. My favorites are the 5200 lb axles with the 12" brakes. Of course, with your Scamp, the bigger ones would be ridiculous overkill. What size do they normally come with from the factory?

I am a big advocate for brakes, and I keep them adjusted to be aggressive enough that I can always feel them working. Because of that, they get more use than most, I suppose. And when they are not right, I know it. There I was at the Oliver Rally, climbing around under the trailer, adjusting the brakes. But it was worth it as they came back to life.

One of the reasons I like the new trailer I ordered (HQ19) is that it has 12" brakes. I've had these before and put a set on a trailer that I switched over from surge brakes to electric. They are sweet.

[Paul O.]

This is from the e-trailer page:
How Do Self-Adjusting Brakes Adjust and Does it Work Going Forward or Reverse

Question:
I remember back in the day when cars had self adjusting drum brakes, the driver had to back the vehicle up for the self adjusters to work. Their was no instructions with these brakes, is that the way these brakes self adjust?
asked by: John H

Expert Reply:

Self-adjusting brakes # AKEBRK-7-SA do not require that you travel in reverse for them to adjust. They can adjust themselves going forward or backward.

Keep in mind that even self-adjusting brakes require 1 initial adjustment. You could just install them and they would eventually adjust out but until that happens you would have weak brakes. Basically if the brake shoes have to move too far before they touch the drums a pulley spins the adjustment wheel which then takes and adjusts the shoes out a bit further. This would happen in forward or reverse.
expert reply by: Michael H

I bought the brakes from them a couple of years ago. I looked at the mechanism and saw how it would adjust by backing up and applying, but did not go beyond that to see how it would work in the normal (forward) application. So the next time I have to take the drums off, I'll take a second look, to satisfy my curiosity.

[floyd]

Originally Posted by Raspy

floyd,

Mine are the Dexter brand on the Oliver. I've been told that there is a system that self adjusts while going forward, but I have no idea how it works.

I had the drums off, but was so busy concentrating on the bearings that I didn't think about how the adjusters work, or if they are different than the traditional system that adjusts in reverse with application of the brakes. A little bit on each brake application.

Either way, they don't work. And that doesn't surprise me. The ratchet nut adjuster on self adjusting brakes has always been a place for failure with self adjusters. The threads get corroded or gummed up and they won't work.

I like electric brakes, but these haven't been as good as I had expected. Mine are the 3500 lb axles with 10" brakes. My favorites are the 5200 lb axles with the 12" brakes. Of course, with your Scamp, the bigger ones would be ridiculous overkill. What size do they normally come with from the factory?

I am a big advocate for brakes, and I keep them adjusted to be aggressive enough that I can always feel them working. Because of that, they get more use than most, I suppose. And when they are not right, I know it. There I was at the Oliver Rally, climbing around under the trailer, adjusting the brakes. But it was worth it as they came back to life.

One of the reasons I like the new trailer I ordered (HQ19) is that it has 12" brakes. I've had these before and put a set on a trailer that I switched over from surge brakes to electric. They are sweet.

My trailer has 7" brakes on a 2200# axle with a 22° up axle.
For years I have advocated for and even lobbied Scamp to go to a 0° axle.
Also I always wanted 10" brakes.
My new truck has a higher receiver height which requires a 10" drop to tow my 13Scamp.
Scamp now provides a bolt on 0° axle with 10" brakes for the 13.
I'm getting one next week which will raise my trailer about 3", better protect all the plumbing underneath, give it a more balanced look with my new truck, and provide better braking.


Ironically I have just recently installed new 7" brakes complete which work better than any 7" brakes I have seen to date... Oh well