Trailer brake voltage

[3930dave]

With the trailer unplugged I checked voltage at the socket and it was 12.5.

Yes I took it back to the dealer with a load on it. They tested the truck and said it was good. Turn the gain down to 3 and pulled it around the gravel parking lot and said it was stopping good. Well that's great but running 60 and hit the brakes it's not. I don't know if I'm expecting too much but I would think a 10 ton running gear would lock up when empty and controller at max gain. I did adjust the brakes and it helped. Maybe the brakes need time to get worn in.
I know on the enclosed trailer I just replaced the brakes and pulled them apart again and maybe half the shoe is in contact with the drum.
Get tired of having to fix things even when new.

I'd check with Tekonsha. An olde-school controller (like I have) is easy to force to maximum output to test with - not sure if the P3 will do that at low speed in auto mode, even at Max gain.

Sometimes you have to outsmart the "smarts" in the box to get it to do what you want.

Anybody else running a P3 ?

Rgds, D.

 

[3930dave]

I have a 99 and a 15 F350. I have an enclosed gooseneck that I just put new brakes on. And I have a new 10 ton gooseneck. Neither of these trailers seem to stop well with either truck. I was checking voltage and at the junction box on the trailers I was getting 9 volts and at the axles 8 volts. Is there that much voltage drop? I can't get the brakes on either to lock up. The 99 truck has a P3 and the 15 has the factory controller.

See what the voltage is on the truck side of the trailer connector doing the above test. Like tcartwri, you may have to upgrade the truck wiring, if the voltage is already low coming into the connector.

I'd also run (just for a stationary test) a good heavy ground from the truck (jumper cables from the battery) and use that as my ground reference when measuring at the trailer.

Hear ya though..... we'd all like to think the point of buying new is that you aren't going to have to fool with it, at least for a long while.....

Rgds, D.

 

[rd_macgregor]

My wife bought a new RAM 1500 this summer and is having nearly identical problems with the factory controller. No matter how the controller is set, there is no way to get any more than a barely-detectable drag from the trailer when the manual controller lever is activated all the way. Took it back to the dealer, who said it was functioning fine. I haven't checked any voltages yet, but hate to think the truck brakes are doing nearly all the work...especially when this is a brand new vehicle. With our old GMC (with after-market controller), it was a delicate business to adjust it so it DIDN'T lock up the trailer brakes...but now, with this truck, that is impossible.

 

[oliver1555]

Check the amperage draw. Each magnet should draw around 2.5 - 3 amps when brakes are fully applied. You have to have large enough wire to handle the amperage. Many trailer manufacturers save money there. Grounding is also a place where many take a shortcut. The grounds should run through the plug on the tow vehicle and to the negative side of the battery if you want flawless braking. Grounding to the frame is a crap shoot. Dexter axle has some good troubleshooting info.
Dexter Axle - Trailer Axles and Running Gear Components - Resource Library

 

[Diamondpilot]

With the trailer unplugged I checked voltage at the socket and it was 12.5. Yes I took it back to the dealer with a load on it. They tested the truck and said it was good. Turn the gain down to 3 and pulled it around the gravel parking lot and said it was stopping good. Well that's great but running 60 and hit the brakes it's not. I don't know if I'm expecting too much but I would think a 10 ton running gear would lock up when empty and controller at max gain. I did adjust the brakes and it helped. Maybe the brakes need time to get worn in. I know on the enclosed trailer I just replaced the brakes and pulled them apart again and maybe half the shoe is in contact with the drum. Get tired of having to fix things even when new.

For the very reasons you described I have converted 2 of my trailers to disc brakes. No comparison!

Chris

 

[Barnbuilder]

To check amperage, do I need to cut a wire and put the meter in the path? Haven't done anything like that since college and that has been a few. I think I need to send the P3 back to Tekonsha. I can put my foot on the brake and the voltage will go up to 3 then back to 0 and start climbing again. Can make for a little pucker factor.

Day I picked the trailer up and got it home.

 

[3930dave]

To check amperage, do I need to cut a wire and put the meter in the path? Haven't done anything like that since college and that has been a few. I think I need to send the P3 back to Tekonsha. I can put my foot on the brake and the voltage will go up to 3 then back to 0 and start climbing again. Can make for a little pucker factor.

Day I picked the trailer up and got it home.

Current will have to be measured in series. I use something like bullet connectors when I have to break into a wire to test like that.

Before cutting into new wiring, I'd try briefly applying 12v directly to that brake control line on the (disconnected) trailer connector, and do a drag test on the trailer. Either use a separate battery, or if GNecks have breakaway switches (?), just pull that.

If you apply 12v to the brake line, and still can't drag the wheels, I'd say it's a trailer issue. On the truck side, I'd focus on getting 12v delivered out of the truck connector (like tcartwri described) before I'd spend time current testing each brake coil - it's a cart/horse issue....... you need full voltage available, before you can get rated current into a load.

For controllers, I'd use something like this for testing at this stage, or forcing full voltage to the control line:

Reese - Brakeman® Compact Brake Control

You may have a buddy with an old idled truck that has one you can borrow, or they shouldn't be big $ to buy new.

My :2cents: Rgds, D.

 

[oliver1555]

To check amperage, do I need to cut a wire and put the meter in the path?

You can open the plug, remove the brake wire, and run power from the plug, through your meter, to the brake wire. Make sure your meter has adequate capacity. Four brakes should show a combined draw upwards of 12 amps with full brake applied.

 

[oldballs]

For the very reasons you described I have converted 2 of my trailers to disc brakes. No comparison!

Chris

Last year I converted my hydraulic surge brakes to electric brakes with the drum/shoe. Now I wish I had gone all the way and converted to disc brakes as well.

Messing with the "star wheel" is a PITA for me. The K-D tool #287 just doesn't fit the star wheel in both directions. If I can't hear/feel the clicks in both directions, I'd just be guessing for each adjustment.

 

[3930dave]

Last year I converted my hydraulic surge brakes to electric brakes with the drum/shoe. Now I wish I had gone all the way and converted to disc brakes as well.

Messing with the "star wheel" is a PITA for me. The K-D tool #287 just doesn't fit the star wheel in both directions. If I can't hear/feel the clicks in both directions, I'd just be guessing for each adjustment.

Haven't tried them yet, but I'd expect that discs on trailer would perform well.

Noticed when I was looking for electric brakes for mine that Dexter makes an auto-adjusting model.

http://dexteraxle.com/i/u/6149609/f/product_flyers/Nev-R-Adjust.pdf

Rgds, D.