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Old 01-02-2015, 06:14 PM   #1
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1984 1750 brakes locking!

My brakes lock when in reverse and I have no idea why. Do I need a controller? This is very, very frustrating.
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Old 01-03-2015, 07:11 AM   #2
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My guess the 7 pin is wired wrong. The brake control wire should be on terminal 2 and I'm guessing it is connected to the center terminal that is for the reverse lights. More that once I have seen brake wiring connected to turn signal wires that actually is pretty funny except to the driver every time they make a turn the breaks lockup when the signal flashes! Yes no matter what you need a controller for the breaks they will not work properly with out one.
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Old 01-03-2015, 10:36 AM   #3
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Does it make sense that everything is fine until I go to back it up? I get out and unplug and it backs up fine. I've thought about unhooking the brakes completely as I can hardly feel the camper back there even with a Tacoma. Thanks for the reply!
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Old 01-03-2015, 11:07 AM   #4
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Yes. if the reverse light signal is being sent to the wrong place in this case the trailer brake wiring as soon as you put the vehicle in reverse it applies the brakes. A brake controller varies the voltage to the camper breaking system so that it does not slam on the brakes it is proportional to the the TV breaking so if they are being feed from the reverse light wiring it will apply maximum voltage to the breaks locking them up as soon as you put the truck in reverse.
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Old 01-03-2015, 04:21 PM   #5
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Quote:
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I've thought about unhooking the brakes completely as I can hardly feel the camper back there even with a Tacoma. Thanks for the reply!
Hi Tego,

Your camper has tandem axles does it not? According to the brochure the camper has a 4,200# GVWR which forces a brake requirement in most all states.

The brochure says it is around 2,300# empty, so with some kind of camping gear you are into a trailer weight that needs brakes.

Now the issue is, is the truck wired wrong or the camper? It sounds like what mainah is saying, your brakes are tied into the reverse circuit either completely or in parallel with the normal brake pin in the 7 wire cable.

On your brake controller in the truck, if you press the manual button all the way in and just inch the truck forward a little can you feel the brakes dragging hard? or nothing? Dragging hard is like it is suppose to be with the manual lever on full power. Nothing at all means there is a problem with the normal brake wiring.

After that test, then put it in reverse and try to back up a little. Does it lock up right away? If so this points to a wiring issue.

Somewhere on the camper there is a junction box. Follow the 7 wire cord back to the camper and find out where it goes into that junction box. Open it up. The reverse wire is often a yellow wire in the 7 wire cable. It should be left hanging loose, wire nutted dead ended or taped off. (assuming you have no back up lights on the camper) If by chance the yellow wire is spliced to the heavy blue brake wire in the 7 wire cable, that is your problem.

If your 7 wire outlet on the truck came from the factory, odds are high the issue is in the camper. I would start at that junction box first to prove out it is OK. If someone wired in your 7 wire outlet on the truck, then it is suspect too.

Some of the older campers had back up lights, does yours? It would most likley be a clear section in the red tail light. If so, we could use that as part of the trouble shooting too to see what it is or is not doing. If the back up lights come on when you apply the manual lever on the brake controller, yup there is a wiring issue.

Hope this helps and good luck

John
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Old 01-03-2015, 05:24 PM   #6
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The camper has new lights and they work fine. Yes it's a tandem axle and it had back-up lights originally. I don't have a brake controller. Thanks
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Old 01-04-2015, 06:39 AM   #7
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The Tacoma with a tow package comes with a 7 pin wired for every thing so most likely a "expert" did some trailer end wiring or replaced the socket it really is the only thing that would cause your issue as you say "it does not do it unplugged" Just about any thing factory wired will have a connection to reverse lighting wiring even if the trailer has no lights it also locks out the surge brakes found on most boat trailers so that they don't apply when you try to back the trailer up. Many states (like Maine) put the GVW of a trailer at 1000# beyond that they require brakes the Tacoma manual also states 1000# and up. It will be a lot nicer tow with brakes if your truck came with the tow package there is a harness in a plastic bag that connects to the truck wiring it will have to be wired to a controller then plug into the truck wiring. Open the socket that is on the trailer and remove the wire that is connected to the center post on the socket plug it in a try it. if that cures your problem it needs to be connected to pin #2 that matches the truck wiring for the brakes. Colors on an old trailers over the years are suspect but in theory it should be blue.
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Old 01-04-2015, 08:37 AM   #8
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Quote:
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The camper has new lights and they work fine. Yes it's a tandem axle and it had back-up lights originally. I don't have a brake controller. Thanks
Once you get this reverse lock up issue fixed, it would be best to get a brake controller. There are many reasons why it is good to do this. If you do get one, research it and get a "proportional" type/brand. The Prodigy is a good one and many have them. There are other brands which are good too, just stay away from "timed based" controllers. While they do work, the proportional work better for not a lot more money. In some cases only $10 more.

There is a good thing in all this, in many cases powering the brakes from an alternate source (the reverse lights) other than the brake controller and back feed the brake controller to later burn it out pending what band you have. In your case you missed this expense, but for sure sort out this reverse lock up issue before installing the brake controller.

I agree with mainah, this points to the issue being in the camper wiring. Try that junction box on the end of the 7 wire cable. If the cable had an all molded plug to the cable, then the plug end is good. If the plug is a spliced on plug to a cable, then it might be mixed up in the plug on the wrong pin.

Do you have a wiring diagram of what it is suppose to look like? A standard trailer wiring diagram for a brake axle trailer will work.
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Old 01-04-2015, 09:20 AM   #9
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Brakes

Quote:
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The camper has new lights and they work fine. Yes it's a tandem axle and it had back-up lights originally. I don't have a brake controller. Thanks
I don't understand how these brakes will ever work properly without a brake controler. Unless I'm missing something here.
I wouldn't trust this set up unless it is a pop up trailer.

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Old 01-04-2015, 01:03 PM   #10
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If I unhook the brake wire completely it would be lock-up problem solved, correct? Does anyone think that it originally had back-up lights is the problem? It has a brand new Hopkins plug installed by the previous owner. The brake lights and turn signals work correctly.
By the way, as a New Englander, I won't be camping for at least four months. I'm just trying to solve these issues now rather than be pressed to get it fixed later.
Thanks all for the help.
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Old 01-04-2015, 02:00 PM   #11
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Quote:
Originally Posted by Tego View Post
If I unhook the brake wire completely it would be lock-up problem solved, correct? Does anyone think that it originally had back-up lights is the problem? It has a brand new Hopkins plug installed by the previous owner. The brake lights and turn signals work correctly.
By the way, as a New Englander, I won't be camping for at least four months. I'm just trying to solve these issues now rather than be pressed to get it fixed later.
Thanks all for the help.
It simply sounds like the trailer brake wire was wired to the wrong pin of the trailer 7-way plug. That would be a simple fix, but John is right.. The laws require the use of a trailer brake controller in the tow vehicle. That is a safety device and is required for a reason. No matter how it "Feels" behind the truck, under normal driving conditions. It would be in an emergency situation, that you could be severely hurt, or killed, because the trailer had no operating brakes. Were you to survive a crash and an investigation determine that you had no operating brakes on the trailer, you would be fully liable and in a heap of trouble.

Do yourself a big favor and look at the following diagram:



It sounds as if your trailer's brake wire is in position 7, in the connector on the right side of the picture. If so, remove it and put it in position 2. Get yourself a trailer brake controller and hook it's BLUE wire to position 2, in the connector on the truck. (Left side of the picture.) Whatever you do, don't compromise yours, or anyone else's safety.

This issue can be something as simple as one mis-wired contact, by the previous owner. If your camper doesn't already have backup lights, then the center pin, #7, will be unused.
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Old 01-04-2015, 03:26 PM   #12
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I have a T1700 and tow it with a Tacoma it's is basically the same camper you have you really want trailer brakes and you want all 4 wheels to work you will not stop it in an emergency situation with out them. I know right away if there is only one bad brake magnet out of 4 it’s a completely different world once the trailer brakes work.
In the picture EMD driver posted the center pin marked auxiliary power (pin 7) is for the reverse lights or in most cases they are used to disable boat trailer surge brakes the bottom line that connection is connected to your truck's reverse light circuit at the factory. Now if there are two wires on that terminal one does not belong there if your trailer reverse lights work. That pin only has power when the truck is in reverse. Now here is what a brake controller does, during normal braking it only supplies a low voltage current to the brakes it follows the amount of braking the TV is doing as you find your self in a situation where heaver braking is needed the controller sends more voltage to the trailer brakes making them work harder too. At no point except a full brake lockup with the TV do the brakes receive full voltage. What is happen with yours it is getting a full voltage signal from some where it shouldn't effectively locking them up. There are two types of modern brake controllers a time delay and a proportional one the time delay ones are cheaper and do not work as well. The proportional ones follow the deceleration rate of the TV and IMHO they are far better.
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Old 01-04-2015, 08:51 PM   #13
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Does anyone think that it originally had back-up lights is the problem?

It has a brand new Hopkins plug installed by the previous owner. The brake lights and turn signals work correctly.
To the first question, no. Back up lights are a good thing when they work correctly. Originally having back up lights is not part of the problem.

A brand new Hopkins plug installed. That is now suspect where the problem can be. As Gary and Mainah said, check that plug odds are high the auxiliary wire the the brake wires are not correct. And all the other brake lights, body lights and turn signals may be correct. The actual brake lights on the camper are "not" part of the wheel brake circuit. The brake lights are totally separate from the wheel brake circuit.

This may be an easy fix if the new plug is mixed up. Then go get your new brake controller setup before camping season comes. If you need help with the brake controller, we can help with that too.

Hope this helps

John
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Old 01-05-2015, 06:02 AM   #14
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Every single pin on the factory Toyota socket does some thing they have a specific purpose from charging your camper battery to lighting your camper reverse lights if so equipped. It's like dialing a wrong number if it's connected to the camper wiring incorrectly you will get to talk to some body but not who you really wanted to. If there are no reverse lights absolutely nothing would happen when reverse was selected because there would be no connection on the camper end. Now if some one connected the brake wire to that terminal then some thing would happen, your brakes would lock when you selected reverse in the truck. If the brake wire was connected to the left turn signal terminal the brakes would lockup every time the left turn signal blinked.
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