2001 Ford F350 brake lights on permanently

skidboot · Posted at Sat Oct 31, 2009 9:46 am

Electrical problem
2001 Ford F350 V8 Two Wheel Drive Automatic 97,000 miles

I noticed the brake lights ( both rears and upper cab lights) on when I shut the truck off after a short trip ( 4 miles) towing an 8,000lb trailer. The power light on my brake controller was also on. I disconnected the brake controller, no change. I removed the fuse for the brake lights, and they remained on. Everything works fine, including the brakes. I made sure the parking brake wasn't on. The only way to get the lights to go off is to disconnect the battery. Last brake job was about 30,000 miles ago. No problems since then

merlin2021 · Posted at Sat Oct 31, 2009 9:58 am

Check the BOO(brake on off) switch on the pedal arm. Unplug it and test switch for proper continuity. An OHM meter will show OL when pedal is in released position, and zero ohms when pressed. If readings differ, replace the switch, if reasdings are OK inpect the wires to the switch.

skidboot · Posted at Sat Oct 31, 2009 10:23 am

I disconnected and removed the BOO switch completely, and the lights are still on!

merlin2021 · Posted at Sat Oct 31, 2009 10:26 am

Something tells me your trailer wiring needs to be looked at, you have a short to power to the brake lights...look there.

skidboot · Posted at Sat Oct 31, 2009 10:38 am

the trailer is not attached to the vehicle at this time

merlin2021 · Posted at Sat Oct 31, 2009 10:49 am

Right, but it does have a connector for the trailer light? And it's wired into your lights? right?

skidboot · Posted at Sat Oct 31, 2009 10:55 am

that's correct

merlin2021 · Posted at Sat Oct 31, 2009 11:07 am

These are the wires that most likey have the short, start there!

skidboot · Posted at Sat Oct 31, 2009 11:21 am

I disconnected the trailer lights/brake connector from the main wiring loom under the bumper and the lights are still on. I can't see any evidence of any obvious problem with the wiring from where it comes out of the loom to the back of the plug for the trailer

merlin2021 · Posted at Sun Nov 01, 2009 9:01 am

On the steering column find the connector for the multifunction switch(wiper and turn), and unplug it, tell me if the lights go out now, if so, replace multifuntion switch.