Steve in VA
Well-known Member
- Location
- Natural Bridge Virginia
The battery should be charging off the prime movers. If that lead isn't working, then the battery will drain. The battery should only be of concern when activated by the breakaway switch. I don't believe joining the +/- wires to bypass the battery gains you anything.
?? If the brakes don't work now when activated by the tow vehicle controller, connecting break away wires together will do nothing to fix that issue. The circuit remains open until the break away plug is pulled. Many trailers do not have the 12v charge wire from the 7 way plug wired into the breakaway battery to keep it charged. Too many people wrongly assume the battery will charge from the tow vehicle. Some do, some don't. Neither my gooseneck flatbed, my enclosed car trailer, nor my travel trailer are wired from the factory to charge the break away battery.
Good application for a solar charger?
Jim.ME
Well-known Member
- Location
- central ME
The brakes should work even with a dead battery or even no battery. As Scott 730 posted the battery does not apply the brakes until the pin is pulled from the breakaway switch, closing the contacts to send battery power to the brakes. Do not hook plus and minus wires together, if you need to do anything unhook the wires from the battery and tape the ends up individually.
It sounds like you may need a new battery, but you also need to find the cause of the brakes not working. That is either in your tow vehicle wiring or the trailer wiring.
Hemmjo
Member
NO you cannot do this!! IF your trailer is wired so the tow vehicle can charge the battery, Connection those two wires will provide a short circuit for the tow vehicle charging system. HOPEFULLY there would be a fuse in that circuit to protect the system from that calamity.
greenmech
Well-known Member
- Location
- Lakeville MN
I think he meant the brakes didn't work when the trailer is disconnected and breakaway switch is pulled. I could be wrong tho. Ron MN
Jim.ME
Well-known Member
- Location
- central ME
I interpreted his post as saying the "emergency" battery was dead and he wanted the brakes to work, I don't see that he said he pulled the pin from the breakaway switch. I am assuming his saying emergency brake means breakaway braking applying the trailer brakes.
If his trailer is wired correctly the brakes will work without the breakaway system, he does not need to connect any wires together to bypass the breakaway battery. Just unhook the battery and separately tape the individual battery wire ends up insulating them from contact with each other or anything else to prevent sort circuits in the charging or braking sides of that system. The trailer will have no breakaway braking if this is done.
Of course, we are all assuming this is a correctly wired 7 pole system capable of charging the battery. We have no info on how the "not charging" was determined. what he posted sounds like there is power there; however, the battery is not accepting a charge.
Him saying the battery is not taking a charge indicates to me a bad battery. If there is no charging power going to the battery then it would sound like a wiring problem in either the towing vehicle or trailer. The battery could have gone bad due to lack of charge caused by the lack of use (which should be charging it, if things are wired correctly) he mentioned.
If the battery is not charged/dead the brakes won't apply if the breakaway switch pin is pulled as a test.
If one pulls the pin on the breakaway switch and tries to use that as a parking brake the battery will go flat in a very short time, it is not intended to be a parking brake.
Correctly wired, even with the trailer cable connected to the tow vehicle, the breakaway battery power will apply the trailer brakes when the breakaway switch pin is pulled. The breakaway switch sends power from that battery to the brakes, any time those switch contacts are closed, if working correctly.
Bottom line, no breakaway battery power there is no breakaway (emergency) braking, but the regular braking should work through the brake controller, provided the wiring is correct.
Steve in VA
Well-known Member
- Location
- Natural Bridge Virginia
I totally agree with you and tried to say the same. I recently encountered a trailer with a dead battery. It turned out that the 7 pin round was not connected to route prime mover 12v to maintain the battery. He had been using the trailer successfully for years because the battery was only in the loop when/if the breakaway switch was activated so he was unaware of the dead battery.
Jim.ME
Well-known Member
- Location
- central ME
As I said if your vehicle and trailer are wired correctly the breakaway battery is only intended to apply the brakes if the trailer breaks away from the tow vehicle and the pin gets pulled from the switch. If the regular brakes are not working that battery is not your problem; it is wiring (tow vehicle and/or trailer) and or regular trailer brake system components.
Installing the neighbor's battery should not have made a difference with your regular brakes. That sounds to me like in changing the battery you disturbed something that had lost connection and it got moved and made connection again.
Is this the 7-wire flat blade plug system? Start by confirming the ground circuit wiring is good from the vehicle to trailer ground. The drawing below is typical for a breakaway system on a trailer. You can see removing the battery will have no effect on regular breaking.
OK, so upon thinking about this some more............. IF there is a dead short in the + wire between the breakaway switch and where that wire connects to the main brake wire harness it could cause the brakes to not work with the vehicle brake controller.
My buddy has been charging the 24F battery in his dump trailer with the charging wire from his pickup, and using that battery to also service the breakaway. I asked him if he was disconnected the umbilical before raising the dump, he says no. I asked if he was blowing the fuse in the charging circuit when he did that, yep, why? It was trying to pull power from the truck when the pump motor was running, and poof goes the fuse
Jim.ME
Well-known Member
- Location
- central ME
And it should be blowing fuses in the tow vehicle if that is the case, which he has not mentioned, and why I posted "Bottom line, no breakaway battery power there is no breakaway (emergency) braking, but the regular braking should work through the brake controller, provided the wiring is correct."
Steve in VA
Well-known Member
- Location
- Natural Bridge Virginia
Agree. There appears to be a lot of disparate information.
All trailer brakes aren't wired the same. This is something you should take to a professional until when and if an experienced friend or neighbor finds time to help you with hands on. There's simply too much risk involved attempting this long distance. As you can see from what has been said to this point, what we hear is often not what you said and what you think we said is often not what we meant at all. Us old hands even have trouble understanding. one another sometimes.
When I first got my Fruehauf deckover tilt, all the lights were very erratic, going out, flashing, even kicking the deck would make them all flash on and off. I was tracking down the grounds, all good thru the base frame, but couldn't find a dedicated ground between the base frame and the deck frame- because there wasn't one, except for the tubes that made the pivot- they apparently had depended on the pivot to carry the ground. Probably worked OK when new, but it's a 1968 trailer, and the pivot is a little crusty. I added a 10 ga wire between the frames, poof, no more problems
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