The truck has been sitting for the last week or so. When I started her up yesterday, the brake light on the dash stayed on.

Brake fluid is OK, the parking brake is fully released, brakes work fine.

Any ideas or suggestions??????

 

Is the ABS light on? Does the speedo work?

Possibly it's the sensor on the rear axel. There is a thread going on this now:
https://www.dieseltruckresource.com/...brake+light+on

 

You can reset the light by a really hard push on the service brake pedal.

 

The ABS light is off and the speedo works. I'm at work now but I'll try and set the service brake to it's maximum this afternoon.

 

Mine's doing the same...about a week ago it started doing it and I could pull up on the parking brake and it would go out...just too lazy to crawl under the dash and check out the switch...now it stays on all the time...