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Tagged: TRAILER BRAKES LOCKING UP
Pigtail can bite. As I mentioned, it bit me also. That being said, the thing does hang out in the wind, and moves constantly. Metal fatigue is not that unlikely.
My last boat never had this happen. We had this cocker spaniel that about once a year would gnaw the dad gummed pigtail off the trailer. So mine was never more than a year or so old. 🙂 I’ve had to replace my current boat’s pigtail once, as I mentioned. My failure was the ground wire, caught because the lights were flickering going down the highway.
I do not know what is happening, but I post the following, then find a formatting glitch, edit, save, and post disappears. Hopefully this one will work. I modified this somewhat to make it clearer and more organized.
To debug a trailer that locks the wheels when you back up, follow the following steps in order. This gives you the shortest path to a fix, without repeating the same test multiple times, and more importantly, without omitting a step and missing the real issue.
(1) Get a helper. Have them sit in your truck with the ignition turned on (but not cranked to keep noise down). Have them put the truck in reverse while you hold your ear near the reverse lock-out solenoid (it is in the front of the trailer, where you see the brake line come out of the actuator and heads toward the back of the trailer frame.) When you see the back-up lights come on, you should hear a distinct click from the solenoid. I am going to assume this is not the case if you are sure your truck and boat lights are working correctly, AND that your truck backup lights are working. And note, SOME trucks use a different circuit for the trailer backup light power, you might have a fuse inside the truck for this. Don’t forget to check this.
(2) Next, disconnect the wiring harness between the truck and trailer. This test will only use the connector on the truck side (female connector). Take a voltmeter and put the + (red) probe in the socket on the connector that matches up with the blue wire. Put the – (black) probe in the socket on the connector that matches up with the white wire. With the ignition on, truck in reverse, and voltmeter turned to measure DC volts, you should see something in the +12 to +13 voltage range. If not, you have likely located the problem. Until you get 12v between blue wire and ground, the reverse lockout on the trailer will not work. Some trucks have a separate fuse for the trailer connector backup lights. In any case, you have to get this fixed before you go any further.
(3) now re-connect the wiring harness once you get that +12v on the blue wire, and again have your helper turn ignition on (no need to crank truck and make extra noise). Then have him/her put the truck in reverse while you keep your ear close to the solenoid. If you hear it click, everything should work. Let’s assume it does not click.
(4) If you don’t hear the click, look at the blue wire from the solenoid. It should go to the trailer connector. Make sure it wasn’t pinched if you have a swing-away tongue. Also make sure it wasn’t pinched/snagged/frayed/etc between the trailer and truck. As an aside, I had this happen on my previous boat and it turned out to be in the trailer harness. A wire maybe 1′ from the connector had apparently fatigued and broken. So power to the solenoid is key.
(5) Unplug the connector again and you do not need the truck turned on and you can let the helper go for a bit. All tests beyond this point refer to the trailer-side connector, not the one from the truck. You can, assuming you have an ohmmeter, plug one probe in the trailer connector blue wire. Use other probe to the blue wire near the solenoid to see if you have continuity. If you do, then keep that probe in the blue connector and touch the other to the solenoid body. No continuity? Replace the solenoid.
(6) if you have continuity to the solenoid body, take the probe and measure resistance between blue wire on trailer harness and the white ground wire on the harness. Got continuity? Then everything on the trailer seems to be working (the solenoid can still stick, but that is much less common than just having the coil burn out.) If you have continuity, and you are not hearing the solenoid click, it is most likely bad.
(7) If there is no continuity, it may be that you have a bad ground from solenoid to trailer frame. Usually the solenoid grounds through whatever it is attached to. But that’s a lousy ground. I always run a real ground wire (most solenoids have a threaded hole or two you can use) to get a good ground from the solenoid body directly to the trailer harness white wire. Before you quit, you should have connectivity from the blue trailer harness socket to the white trailer harness socket. Once you have that, plus the 12v from the truck, if the trailer brakes still lock up when backing, replace the solenoid.
For this thing to work, you need 12 volts between blue/white wires coming out of truck connector, and you need continuity from the blue to white wires on the trailer harness. If you have all of that and you still can’t back up, you can pretty well bet it is the solenoid. You can always use the reverse lockout key to see if that lets you back up OK. IF so that at least says the rest of the braking hardware seems to be ok…
Good luck…
scrappy% vi brakes
scrappy% cat brakes
To debug a trailer that locks the wheels when you back up, follow the following steps in order. This gives you the shortest path to a fix, without repeating the same test multiple times, and more importantly, without omitting a step and missing the real issue.
(1) Get a helper. Have them sit in your truck with the ignition turned on (but not cranked to keep noise down). Have them put the truck in reverse while you hold your ear near the reverse lock-out solenoid (it is in the front of the trailer, where you see the brake line come out of the actuator and heads toward the back of the trailer frame.) When you see the back-up lights come on, you should hear a distinct click from the solenoid. I am going to assume this is not the case if you are sure your truck and boat lights are working correctly, AND that your truck backup lights are working. And note, SOME trucks use a different circuit for the trailer backup light power, you might have a fuse inside the truck for this. Don’t forget to check this.
(2) Next, disconnect the wiring harness between the truck and trailer. This test will only use the connector on the truck side (female connector). Take a voltmeter and put the + (red) probe in the socket on the connector that matches up with the blue wire. Put the – (black) probe in the socket on the connector that matches up with the white wire. With the ignition on, truck in reverse, and voltmeter turned to measure DC volts, you should see something in the +12 to +13 voltage range. If not, you have likely located the problem. Until you get 12v between blue wire and ground, the reverse lockout on the trailer will not work. Some trucks have a separate fuse for the trailer connector backup lights. In any case, you have to get this fixed before you go any further.
(3) now re-connect the wiring harness once you get that +12v on the blue wire, and again have your helper turn ignition on (no need to crank truck and make extra noise). Then have him/her put the truck in reverse while you keep your ear close to the solenoid. If you hear it click, everything should work. Let’s assume it does not click.
(4) If you don’t hear the click, look at the blue wire from the solenoid. It should go to the trailer connector. Make sure it wasn’t pinched if you have a swing-away tongue. Also make sure it wasn’t pinched/snagged/frayed/etc between the trailer and truck. As an aside, I had this happen on my previous boat and it turned out to be in the trailer harness. A wire maybe 1′ from the connector had apparently fatigued and broken. So power to the solenoid is key.
(5) Unplug the connector again and you do not need the truck turned on and you can let the helper go for a bit. All tests beyond this point refer to the trailer-side connector, not the one from the truck. You can, assuming you have an ohmmeter, plug one probe in the trailer connector blue wire. Use other probe to the blue wire near the solenoid to see if you have continuity. If you do, then keep that probe in the blue connector and touch the other to the solenoid body. No continuity? Replace the solenoid.
(6) if you have continuity to the solenoid body, take the probe and measure resistance between blue wire on trailer harness and the white ground wire on the harness. Got continuity? Then everything on the trailer seems to be working (the solenoid can still stick, but that is much less common than just having the coil burn out.) If you have continuity, and you are not hearing the solenoid click, it is most likely bad.
(7) If there is no continuity, it may be that you have a bad ground from solenoid to trailer frame. Usually the solenoid grounds through whatever it is attached to. But that’s a lousy ground. I always run a real ground wire (most solenoids have a threaded hole or two you can use) to get a good ground from the solenoid body directly to the trailer harness white wire. Before you quit, you should have connectivity from the blue trailer harness socket to the white trailer harness socket. Once you have that, plus the 12v from the truck, if the trailer brakes still lock up when backing, replace the solenoid.
For this thing to work, you need 12 volts between blue/white wires coming out of truck connector, and you need continuity from the blue to white wires on the trailer harness. If you have all of that and you still can’t back up, you can pretty well bet it is the solenoid. You can always use the reverse lockout key to see if that lets you back up OK. IF so that at least says the rest of the braking hardware seems to be ok…
Good luck…
Unlike you to double tap there OT57… must be a new tablet or iPad thingy ma bob.
BCB
I didn’t double tap. Not sure exactly what happened (I actually did it 3-4 times). I would paste text into this window. Then submit. Then looking at it there would be a formatting mistake (no blank line between each step, one or two missing.) I would then edit, fix the change, and hit “save” and suddenly I would not see my post at all, just the same last post as when I started.
In any case, I got it close enough to be readable.
Here’s a test edit. BTW I am using my same MacBook that I have used for the last two years. And I used another MacBook prior to that. Not much of an iPad myself. And while I use an iPhone, I avoid typing on it at all costs. Afraid it will cost me a new phone when I throw old phone through door. 🙂
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