Stoplights stay on all the time - even after battery switch turned off

[PureMayhem]

I just picked up my first MV this week from San Marcos, TX (1990 M9323A2) . Successfully made it home to Houston but on the way home Dave, who was following behind us in his truck let me know that my brake lights were staying on all the time. When I got home and turned everything off the brake lights continued to stay on. I went ahead and disconnected the batteries until I can get this fixed. When I unplug the brake switch the lights stay on. I haven't checked the resistance on it yet and I haven't checked the battery switch yet but will do that this weekend. I am thinking I may have more than one problem happening at once. I have a short to voltage somewhere and maybe a bad brake switch or a misadjusted brake pedal. Any thoughts?

 

[NDT]

The brake lights stayed on with the 3 lever switch in the off position?

 

[CBR Metalworks]

M932a2 tractor? If so, make sure the trailer brake lever on the right side of the steering column is all the way 'up'. If you typed wrong and have a cargo truck this does not apply.

 

[M1075]

Ditto

 

[PureMayhem]

M932a2 tractor? If so, make sure the trailer brake lever on the right side of the steering column is all the way 'up'. If you typed wrong and have a cargo truck this does not apply.

Yes I fat fingered the type. It is a M923A2 Cargo.

 

[PureMayhem]

The brake lights stayed on with the 3 lever switch in the off position?

Yes all switches are set to off.

 

[NDT]

This is very unusual. I suspect something is wrong with the 3 lever switch. In the off position, all lights are deengergized. The top lever pointing straight up, correct?

 

[PureMayhem]

This is very unusual. I suspect something is wrong with the 3 lever switch. In the off position, all lights are deengergized. The top lever pointing straight up, correct?

That is correct.

 

[juanprado]

more issues than that as with the battery switch off there should be no power period even with the light switch on. Secondarily with the light switch off, there also should be no power.

The stoplight switch is air activated pressure switch on the inside frame driver's side in the vicinity of the fuel tank. Nothing on pedal. When pressure is applied, the switch completes the circuit but it is only hot with battery switch on and light switch set to service drive and brake (don't remember exact wording as I upgraded to LED) and battery switch on

 

[PureMayhem]

I just picked up my first MV this week from San Marcos, TX (1990 M9323A2) . Successfully made it home to Houston but on the way home Dave, who was following behind us in his truck let me know that my brake lights were staying on all the time. When I got home and turned everything off the brake lights continued to stay on. I went ahead and disconnected the batteries until I can get this fixed. When I unplug the brake switch the lights stay on. I haven't checked the resistance on it yet and I haven't checked the battery switch yet but will do that this weekend. I am thinking I may have more than one problem happening at once. I have a short to voltage somewhere and maybe a bad brake switch or a misadjusted brake pedal. Any thoughts?

Update - I finally got back to the truck and took the lenses off the composite lights and it is not the brake light staying on, it is the turn signals both staying on all the time. I unplugged the turn signal switch and the lights went off so now I am thinking the problem is in the flasher because I checked the turn signal switch and it is working correctly. Can anyone tell me if both filaments in the light bulb turn on for the turn signal or for the hazard or both. These bulbs have two filaments and both are lighting.

 

[doghead]

The bulb has dual fillaments for redundancy. They are a one curcuit bulb.

Take it out and you'll see it has one contact, not two

 

[PureMayhem]

I just picked up my first MV this week from San Marcos, TX (1990 M9323A2) . Successfully made it home to Houston but on the way home Dave, who was following behind us in his truck let me know that my brake lights were staying on all the time. When I got home and turned everything off the brake lights continued to stay on. I went ahead and disconnected the batteries until I can get this fixed. When I unplug the brake switch the lights stay on. I haven't checked the resistance on it yet and I haven't checked the battery switch yet but will do that this weekend. I am thinking I may have more than one problem happening at once. I have a short to voltage somewhere and maybe a bad brake switch or a misadjusted brake pedal. Any thoughts?

Update: I borrowed a light switch and turn signal switch from davo727 and the problem was the light switch.The stop/turn lights are working properly.