Help...Trailer Brakes Locked Up When Reversing

[trishglxk]

We had a small problem on a boat launch ramp this a.m. We started to reverse down the steep ramp, and the trailer brakes locked up. This was the first time we reversed down a steep incline while towing, and the surge brakes on the trailer locked up. This was not supposed to happen. (We temporarily fixed the problem, but we still have the problem).

 

The trailer we tow has a 5-pin flat connection. Our 2007 Expedition Limited came with just the 4-pin connection--no towing package. The 5th pin in the flat-5 connection controls our trailers surge brakes. So, we brought it into U-Haul, who for $24 put a flat-five adapter on the Expedition. The Expedition actually had the 5th blue wire already in the wiring harness--it just wasn't connected to anything at the rear of the vehicle.

 

I don't believe U-Haul made any wiring connections inside the vehicle. Perhaps they assumed the Blue wire that came with the wiring harness was already properly connected in the front of the vehicle. Did they assume wrong?

 

 

Any help will be appreciated.

 

Thanks, Trish

[derekrice]

I'm a little confused on your post. Do you have surge brakes or electric brakes?

 

Surge brakes have nothing whatsoever to do with the wiring harness on your truck. The pressure exerted on the hitch ball by the forward momentum of the trailer triggers the hydraulic system to apply the brakes. This system will almost never apply itself in reverse.

 

If you have electric brakes on your trailer, then most applications I have seen also include a brake controller mounted near the dash that regulates the brake application. There is usually an adjustment than can be made with a dial so that your brakes don't lock up when you "tap" them.

 

The Expy is pre-wired for this set up, you should have a wire harness in a plastic bag under the floor next to your jack. This will plug in under the dash and the loose wires go to the aftermarket controller.

 

I've had both set ups, electric for a toy hauler and surge for a boat. If you can clarify, maybe I can help.

[trishglxk]

Hi Derek....thanks for offering to help....again.

 

This is a classic case of a little bit of knowledge making me dangerous, but here goes.

Our boat trailer has surge brakes. When we back it up, the braking system senses the pressure on the tongue the same as if you were applying your brakes. The trailer brakes then go on and you can't back up. (If you're reversing slowly on level ground, sometimes there's not enough pressure on the acctuator to cause a problem. We had a problem this weekend attempting to back the boat UP an incline.

 

Something is needed to tell the trailer you are backing up and not stopping. I believe this is done by having a fifth wire in your system attached to the Expedition's backup lights. It keeps the trailer from locking up while you are backing up. We were able to maually neutralize the breaking system with a lockout key that came with our trailor, but you have to get out and put it in place each time you plan to back up. You may also have to tape it in place to keep it where you want it. Not a long-term solution.

 

It sounds like I falsely assumed the blue electric brake wire could be used as this Fifth wire. But the U-Haul guy should have been smarter than me. He did replace the 4-pin connection on the Expedition with a 5-pin connection...But it sounds like whatever wiring is required to make this work was not done, or not done properly.

 

I'm just looking for enough guidance so I can communicate effectively with the tech at U-Haul.

 

Thanks, rish

[derekrice]

Trish:

 

Makes a little more sense now since you were backing up the hill. From this information it sounds like there may be nothing you can do that you haven't already figured out. Surge brakes are generally not associated with anything electronic especially on a boat trailer which is designed to get very wet. The fact that you had to get out to put a pin in to disable the actuator leads me to believe there is no electronic control to disable your surge brakes.

 

Which leads us to the mysterious blue wire. If there is in fact a way to disable your surge brakes electronically I would have to believe you need more than one wire and there would definitely need to be a switch or control in the truck to trigger it. You wouldn't want this to be enabled every time you reverse thus you would need some sort of lockout mechanism, which would pretty much eliminate the truck coming pre-wired to do this for you automatically.

 

Really this is a boat trailer issue and you might get more help on a boating board. Try GoBoatingAmerica.com, there are lots of knowledgeable folks there. Also, if this is a new boat and trailer, I would contact the dealer as they can probably answer the question quickly over the phone. If it's not, find a local boat dealer with a big maintenance operation and take it over there and show it to them.

 

Nothing against U-Haul, but I believe you are correct about them and don't think they are going to be much help to you. Actually, I don't think they should have installed the adapter without asking a few questions. BTW most electric brake controllers run off the 7 pin set up.

 

Good Luck!

 

DJR

[trishglxk]

Thanks, Derek...

Good Advice--thanks for taking the time to post back.

Regards,

Trish

[NLPRacing]

Thanks, Derek...

Good Advice--thanks for taking the time to post back.

Regards,

Trish

 

I used to have a boat trailer with surge brakes and when I backed it up, there was a lever on top of the brakes near the hitch that I would pull that disabled the brakes. There should be some kind of lockout.

[boegey]

I used to have a boat trailer with surge brakes and when I backed it up, there was a lever on top of the brakes near the hitch that I would pull that disabled the brakes. There should be some kind of lockout.

 

Trish,

 

I've been boating most of my life and have had trailers with surge breaks. Some have a lock out feature such as a lever or a pin as you have but not all. My present trailer, an Eagle brand, has no such lock out. Reversing very SLOWLY, with my trailer, will not cause the brakes to engage or at least not enough to prevent backing. I believe the solution to your problem is your lock out pin that you mentioned earlier.

 

Anyway, your surge brakes function exactly as you described. They have no electrical input but are purely mechanical. Of course, some brand new electro-mechanical device may now exist but I doubt it. If your boat is new, talk to the marine dealer that you bought it from for clarification. If you bought used, you could attempt to contact the manufacturer or the person you bought the boat from. Most boaters are happy to help others if you ask. (It speeds up time to launch their boat if the people in front of them know what they are doing - resulting in lots of cooperation.)

 

I guess I'm echoing Derek but suggest the dealer for answers if your boat was bought new.

 

Boegey

[boegey]

Trish,

 

The neighbor came home yesterday with a brand new shiny boat and trailer. His trailer had surge disc brakes and guess what? He had to have a 5-pin harness added to his vehicle as you described. His particular trailer has the reverse lock out pin as does yours. It turns out the fifth wire in the connector taps into the reverse light circuit. When the tow vehicle shifts into reverse, a solenoid on the trailer does the reverse lock out function in place of the pin. If your trailer is like this one, I'd get the five wire flat connector because it would sure be convenient. However, if your trailer is not like this changing the harness is probably a waste of time since converting your trailer would probably be a bigger pain than it is worth. (Or trading your current trailer for a newer one could be considered - although still spendy for a convenience item.)