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Wiring trailer brakes on 91 Ford 150, what is the red wire with green strip.

I getting ready to wire my 91 F150 with a third party electric brake controller.

Under the dash is a factory wiring harness with 3 wires for connecting a factory brake controller. The 3 wires are Red, Blue, (Red with Green strip).

Heavy gauge Red wire has 12 volt when the ignition switch is on. I assume I can use this wire to power my brake controller. Heavy gauge Blue wire. I assume I can use this wire is to carry the current from the brake controller to the trailer brakes. And a small gauge (Red with Green strip) function unknown.

At the rear of the truck is the other end with 4 wires. White, Orange, Blue, (Red with Green strip). Heavy gauge White wire appears to be a ground. Heavy gauge Orange has 12 volts contantly. (switch on and off) Heave gauge Blue come from the front. (trailer brakes I assume) The small gauge (Red with Green strip) function unknown.

Does anyone know what's the function of the (Red wire with Green strip)? It doesn't appear to be energized when the brake pedal is pressed, nor headlight turned on, nor transmission put into reverse.

Reply to
emcook
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Yes, it's the stop and left trun signal.

For a RV with a 7 pole conductor:

!. White ground

  1. Blue Brake
  2. Green Tail, license, and running lights
  3. Black Battery charge
  4. Red Stop and left turn
  5. Brown Stop and right turn
  6. Aux circuit.

The easiest way is to get a Prodigy controller and the Ford connection that just plugs in the harness at the same time.

MM^^

Reply to
invalid unparseable

At the rear of the truck there are 2 connector plugs.

One plug control has the typical 5 way functions, Left turn, Right turn, Stop, Lights, and I think Reverse. Thats where my existing 4 way trailer plug is wired into. Correction, previous owner cut-off the connector and wired in the 4 way trailer plug

Its the 2nd round 4 wire connector that I'm referring to.

White is Ground. Orange is 12 Volts constantly. Blue comes from under the dash (trailer Brakes I assume) And the (Red with Green strip) that also goes to the factory Brake Control plug under the dash.

I wouldn't seem logical to supply a brake control a left turn feed, nor does the wire energize when the brake pedal is pressed.

Factory wir> > Does anyone know what's the function of the (Red wire with Green > > strip)?

Reply to
emcook

Sorry, then. I have no idea.

MM^^

Reply to
invalid unparseable

No it doesn't, but it is very logical to have the controller feed the brake light circuit, so that if the driver moves the lever on the controller, the brakes light come on to warn the following vehicles.

Whitelightning

Reply to
Whitelightning

That would make sense. I hadn't thought about manually activating the controller and it activating the brake lights.

But some thing has to activate the controller.

I w> > At the rear of the truck there are 2 connector plugs.

Reply to
emcook

Doesn't the controller tie into the vehicles hydraulic brake system at the master cylinder?

Whitelightning

Reply to
Whitelightning

disregard question, quick online check shows I am showing my age. But I think I like the older design that tied into the hydraulics better. very little to go wrong with them, and I don't see any way to apply just the trailer brakes on the three or four 'electronic" time delay units I saw.

Whitelightning

Reply to
Whitelightning

My Prodigy controller has a small lever at the front to manually acitvate the trailer brakes.

DJ

Reply to
DJ

You have to tap into those wires for your lights. I recommend running a main power wire (10ga) back here with a fuse up front, and relays for the different functions, that way you cant overload your trucks wiring and if you get a short in the trailer, it only effects the trailer and not the trucks lights as well.

The orange wire with the constant 12V is for the battery backup charge that all trailers with electric trailer brakes are supposed to have.

You are correct on the Blue wire.. Its for when the brakes are actuated..

What is this wires guage (size)? Another thought is that some systems use a feedback design and this wire might be for that.

Hope this helps out some..

Ford Tech

Reply to
Ford Tech

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