Brake controller wiring

[needlenose]

I just installed a brake controller in my truck. The truck has the factory towing package. The brake controller stays on even when the ignition is off.

Is this by design, or did some previous owner kludge the wiring?

 

[gandalf]

"The brake controller stays on even when the ignition is off." How do you mean? How do you determine it's on?


The brake controller in my truck has a little red light which lights up whenever I apply the brakes. That's the only indication I ever get that it is active, that it is alive. Otherwise it just sits there, waiting for me to bang my knee on it. There is no on/off switch.

 

[F350camper]

Mine stays on for a while, but then turns totally off after some period of inactivity.

 

[ironworker40]

The light or the digital readout on your brake controler should light up when you push on the brake pedal or apply the manual slide switch on the brake controler only. Regardless if the truck is on or off. If it is on all the time you have a short

 

[OLDBULL8]

QUOTE// The brake controller stays on even when the ignition is off.//QUOTE
Are you saying there is power to the controller all the time or that the power to the trailer brakes are ON all the time?


The 12VDC power to the Brake controller should be ON all the time, the 12VDC should go thru a quick resetting 12VDC 15 or 20 Amp circuit breaker depending on how many axle brakes it's controlling.

On your 94 if that's what your installing the controller on, it should have a prewired plug in about in the center underneath of the dash. You have to install a relay and fuse, breaker in the proper places.

 

[needlenose]

It's a new Tekonsha P3 so it has a little digital display. When I first plugged it in(no key on) it just woke up and showed the little Tekonsha slash screen and stayed on. The screen shuts off after 15 min, but if I just hop in and hit the brakes(no key in ign) it wakes up and shows the voltage output.

It's just ignorance on my part. Research indicates it is operating as designed. Unfortunately the instructions don't really explain this and I've never run a controller in this truck before. I just assumed there was something wrong with my 23yo truck.

It is an old Ford after all...

 

[laserjock]

Yes. It will be on regardless of key. The older trucks at least have a dedicated line with fusible link for power to it. I haven't got my p3 installed yet. Hadn't thought about that aspect but I'm glad you say it turns the display off eventually.

 

[needlenose]

Does anyone know where the ground wire terminates coming from the factory female 7-way receptacle towards the engine?

Surely it doesn't run all the way to the engine compartment....

 

[franklin2]

Some did. Some of the older trucks had a rear ground wire that went up into the cab and bolted to the metal behind the radio way up in the dash area. Some also had grounds that went up to the front and bolted to the area beside the radiator. Not sure where your year is grounded.

 

[needlenose]

Some of the older trucks had a rear ground wire that went up into the cab and bolted to the metal behind the radio way up in the dash area.

Oh my..... because that's totally necessary.....

I think I'll just nip the wire and ground it directly to the frame. I have 2 large straps from the battery to the frame in the engine compartment. Apparently they also change the color from white to something else inside the conduit somewhere.

 

[Shawn MacAnanny]

I've had a Tekonsha p3 in my last 5 vehicles from 1993-2015s. The display always stays on and will go off after a half hour or so of not being used. It's definitely the best brake controller I've ever used.

I ran power fused from the battery and ground direct as well as new wiring to the rear. If you're towing over 10k it's more than half your braking power and your only braking power if your engine dies in an auto truck.

 

[madpogue]

You wouldn't want your trailer brakes to fail if anything with your ignition switch wiring failed; this is the same reason your brake lights are not dependent on the ignition switch.