Should Center Pin of Trailer Wiring Carry 12 Volts When Trailer Battery is Connected

Question

Question:

Truck is 2007 F250. Toy hauler trailer has solar. With the battery disconnect OFF I get 13vdc on the trailer pin #4. With the battery disconnect ON I get 13vdc on trailer pin #4 but also get 12.5vdc on the trailer plug center pin #7 which my truck indicates is for backup lamps. Is this normal and/or is this going to backfeed into my truck and cause problems? Worried it might cause truck battery and or alternator problems while plugged in with and without the truck ignition turned on.

asked by: Aaron T

0

Expert Reply:

The center pin of your 7-way really should only have voltage when the reverse lights are on. It's possible the trailer has that circuit also ran as an additional accessory circuit but that's not always the case. It's hard to say if that would be an issue. One easy solution though would be to install the diode part # RM-690 on that circuit of the trailer's wiring. It would prevent the voltage from going back to the tow vehicle.

expert reply by: Jameson C

0

Answer 1

In order to make sure your battery does not backfeed into your 2003 Toyota Land Cruiser all you need to do is add a single diode like the Roadmaster #RM-690. This will install between the trailer battery and 7-Way and only allows power to travel in…

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Answer 2

Yes, you could install the Roadmaster Diodes part #RM-690 on the wiring of a tow vehicle if you wanted to.

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Answer 3

Backlfow preventers are used to prevent water from backfeeding through the water pump and seeping back in to your fresh water tank when hooked to city water. A backflow preventer is also usually installed behind the city water connection to prevent…

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Answer 4

If you wanted to prevent the 12 volt trailer wiring circuit from backfeeding when connected to your trailer's battery you'd have to use a diode like the part #RM-690. This will only allow the current to flow in one direction.

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Answer 5

So I believe one of a couple things has occurred. I would first check to see where they tied the solar panels controller into. This should have been tied directly into the battery itself. They may have connected it before the battery charge…

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Answer 6

For your enclosed box trailer, it is best to let the breakaway battery run the breakaway system and use the accessory battery to power your trailer's interior lights (or other parts). This is the best option because your breakaway battery…

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Answer 7

On a 7-Way trailer connector such as #H20046 the 12 volt wire would connect to any accessory that would need 12 volt power such as a trailer mounted battery or a jack in some cases. You usually do not see them on boat trailers. If you don't…

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Answer 8

Wiring in the parking light diode #RM-690 is easy. All you have to do is locate the wire leading to the parking light bulb. Cut the wire and insert the diode in-line with the wiring. The IN side will be the part of the wire that leads to the front…

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Answer 9

The correct way to fix this would be to install a battery charger like #20011 on each of your break-away systems. This is a reasonably priced option that will prevent the overcharging of your breakaway battery and will also prevent the back feeding…

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Answer 10

The diode #RM-690 can handle up to 120 volts at 24 amps so it should work just fine for your needs provided nothing else exceeds 120 volts at 24 amps. Regarding your picture, most battery chargers or batteries on vehicles say not to ground the…

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Answer 11

If you check out the picture I attached you will see where to install the diodes on your vehicle to install both the Roadmaster InvisiBrake Supplemental Braking System #RM-8700 and the part #HM56304 that you referenced. For a diode kit you would want…

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Answer 12

Since you have connected your Winnebago to both your Jeep and boat trailer and are experiencing the same issue it is likely related to the vehicle wiring on your Winnebago that is the issue. The first thing that I would check would be the vehicle…

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Should Center Pin of Trailer Wiring Carry 12 Volts When Trailer Battery is Connected

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