Trailer Brakes Locking in Reverse

[TXPGE]

Sorry for another thread over this topic. I just joined the site and have read over a few of the other threads but I am still confused. I have a Dorsey trailer(~04 Model) equipped with a surge braking system and disc brakes. I have an awful time backing the trailer into the barn on a level surface. I took a few pictures of the tongue and wiring for you to look at. I'm assuming the white wire should be connected somewhere on the trailer, but a quick look didn't show me anywhere it could visibly go.

Is it possible to completely disable the surge braking system? I have a large truck and the trailer does have disc brakes so I don't even need it. Right now it is certainly more of a nuisance than helpful. It also makes awful noises when slowing down. I hooked the wiring harness up to my vehicle again yesterday and did not see any reverse lights on the trailer lit up when in reverse. Hopefully that will tell you something. Thanks

[WakeSlayer]

Just a WAG, but I would suggest verifying you have a good ground. The reverse lockout is an electrical switch. This has nothing to do with your lighting ground. This is what happened on my Zieman trailer.

[shag]

I second the ground issue. It usually means u don't have a good ground between trailer and vehicle (I.E. there might be a little surface corrosion on the ball or hitch. I have had this exact thing happen and just hooked my breakaway chains back up and got a good enough ground to release the brakes. Sometimes more prominent with an empty trailer as the weight of the boat pushing on the tongue helps with a ground contact issue.
My .02

[HS]

Slayer is right, the reverse lockout is an electrical switch activated by your tow vehicle's reverse lights. But, as I found, a faulty ground can also hinder the process. Is that loose white wire in your photo the ground wire?

As far as disabling the brake, I can't comment, but for backing purposes, you can use a large C clamp on the trailer tongue fitting it just ahead of that large round pin in the slot that drives the brake piston. The C clamp will prevent the pin from sliding forward as you reverse the trailer into the garage, etc. The trailer mfrs. also make a small tab that fits into the notch, which does the same thing, but they tend to fall out in my experience. DHM sent me a "yard tab" which I used when the issue would arise. A cal to your trailer mfr might get this done -- but I think the brake is a component they buy and yours looks just like the one on my trailer, so maybe you can get one anywhere.

Another thing I recently learned that told me it might not have been a ground wire: if that piston is engaged even a little bit from the last bit of momentum of stopping the vehicle, it will prevent the brake lock-out from activating. This can occur if your are on a down hill slope that makes the trailer want to push into the tow vehicle and thus engage the brake piston. To overcome this, on a level surface, ease the tow vehicle forward just a bit to take the pressure off of the brake piston, then try reverse and see if it backs up. Good luck.

I saw an informative animation of how the e-brake works on the DHM trailer web site before they were became California Trailers. It helped me understand how the brake piston worked, etc.

One more thing: that noise you are hearing might mean that your piston needs to be replaced.

[jmo]

Did you recently buy the boat & trailer (used I assume)? It sounds like you have two issues:

1
A wiring issue that is preventing the reverse solenoid from being activated - make sure your wiring set up is connecting the reverse lights on the tow vehicle to the wire for the solenoid.

2
Second problem could be the brake pads are worn out and hence the "awful noise" you hear is the metal backing on the pad rubbing on the rotor. Jack it up and pull the wheel off to verify the pads look okay. Good news is the brakes seem to work...

As a stop gap measure when you need to back up you should be able to pit a pin or screwdriver into a hole in the front of the actuator to prevent it front being compressed.

[Quinner]

If the trailer is equipped with a reverse lockout solenoid you should have a (5) flat connector, or a wire that is hot when the tow vehicle is shifted into reverse. Hard to tell from the pick? Looks like a 4 flat into the round connector (whatever it is called).

[mdvalant]

Was thinking the same thing Q. I don't think the truck is wired for that option.

[TXPGE]

Thank you for the help so far. Yes I bought the boat used at the end of last summer, so I haven't had much use with it yet. Also a first time owner so please forgive my incompetence on these matters. The wiring harness is a flat four pin into the round adapter for a Chevy truck. I believe the white wire is the ground, but I honestly don't really know. I think a good ground is being achieved because the ball is fairly clean and I always use the safety chains.

Sounds like I may not have the reverse lockout solenoid, so Is my only option to remove and replace the piston assembly?

[Quinner]

Actually Mike I was referring to the trailer as having what appears to be a 4-flat, additionally you can see a loose (white) wire before the flat??

That does not mean the tow vehicle does not also have an issue however I am guessing it has a round 7 pin, which if fully wired would have an auxiliary and/or reverse lead included.

[mdvalant]

Duh, yea sorry Q.

You meant what I knew!

[Quinner]

The wiring harness is a flat four pin into the round adapter for a Chevy truck. I believe the white wire is the ground, but I honestly don't really know. I think a good ground is being achieved because the ball is fairly clean and I always use the safety chains.

Sounds like I may not have the reverse lockout solenoid, so Is my only option to remove and replace the piston assembly?

Would bet that is your problem right there. The trailer would need (5) leads if equipped with a reverse lockout. You need to change out the 4-flat on the trailer to a 5-flat or you could even go to the 7-pin like your truck has. If you go 5 flat you will need the same adapter you have from 7-pin (Chevy Truck) to a 5-Flat, unless the one you have has 5 on it. If you do not have any testing equipment bring it to a trailer shop and they should be able to help you out, should be a relatively simple fix......hopefully!

Good Luck

[Rick]

Brakes from UFP in Vista California

The brakes are made by UFP in Vista California. They can send you a yard tab if you contact them. The reverse lockout wire should be blue and be the 5th wire on the flat connector. You will need a 5 pin to 7 pin adapter or as someone said just wire it to a 7 pin and forget the adapter. Any trailer place even U-Haul should be able to do it for you if you don't feel comfortable.

[HS]

Thank you for the help so far. Yes I bought the boat used at the end of last summer, so I haven't had much use with it yet. Also a first time owner so please forgive my incompetence on these matters. The wiring harness is a flat four pin into the round adapter for a Chevy truck. I believe the white wire is the ground, but I honestly don't really know. I think a good ground is being achieved because the ball is fairly clean and I always use the safety chains.

Sounds like I may not have the reverse lockout solenoid, so Is my only option to remove and replace the piston assembly?

No worries, we were all first time owners at one point, and I wouldn't know this unless I was in your shoes at one point.

I see the flat pin to round converter in the photo. Check the flat pin connector again -- if its a 5 pin, 4 will be arranged as male plugs (or female, I forget) and one (the fifth) will be the opposite. I say this b/c I would be very surprised if the trailer had brakes and no reverse lock-out function.

My 2000 Toyota L/C came with a 4 flat pin harness that we had to change to the flat 5 pin for just this purpose.

A good trailer shop or even a U-haul store (or you if you have the meter tool) should be able to help you determine if the signal is getting from the reverse light to the trailer's lock out solenoid. I would do this before changing the piston -- but do check the piston. Your description of the noise you get under braking reminded me of the loud "clunk!" you can hear when the piston is shot.

[TXPGE]

No worries, we were all first time owners at one point, and I wouldn't know this unless I was in your shoes at one point.

I see the flat pin to round converter in the photo. Check the flat pin connector again -- if its a 5 pin, 4 will be arranged as male plugs (or female, I forget) and one (the fifth) will be the opposite. I say this b/c I would be very surprised if the trailer had brakes and no reverse lock-out function.

My 2000 Toyota L/C came with a 4 flat pin harness that we had to change to the flat 5 pin for just this purpose.

A good trailer shop or even a U-haul store (or you if you have the meter tool) should be able to help you determine if the signal is getting from the reverse light to the trailer's lock out solenoid. I would do this before changing the piston -- but do check the piston. Your description of the noise you get under braking reminded me of the loud "clunk!" you can hear when the piston is shot.

Good call, you made me catch my own error. It actually is a 5 pin! I just counted the 4 male pins and completely neglected the female terminal. I do actually have a meter tool. Could someone explain to me where to check and test the solenoid? It looks to me like all of the wires except for the white one (which I still have no idea what it is for) go to the running and turn signal lights. I'm a bit hesitant to begin disassembling the hitch because it looks like it could be a job. Hopefully I am wrong.

[HS]

Well I might have soundeed smart, but this comes mostly from me watching what the trailer guy did. Work the test meter from the tow vehicle back to the trailer, checking the plug first. If you're already seeing the tail lights, brake lights, turn signals and maybe even a reverse light on the trailer tail lights, then the connection should be good (obviously, you'll need someone to put the tow vehicle in reverse with their foot on the brake for this.) Then with the plug connected, and again in reverse, check for the signal under the tongue of the trailer for where the wire connects to the solenoid. I guess that's the moment of truth to know if the solenoid should be working?