I have a 2002 discovery II and the rear brake lights won't turn off(only when the motor is off are the lights off) they just stay on, always. Even when i push the brake pedal they don't turn brighter or anything they just stay the same. What could the problem be?

 

Remove the driverside tail light and look for water ingress and corrosion in the wire harness and bulb sockets.
It is a common problem on early DII's for that tail light to leak and then have brake light problems.

It could also be a bad brake light switch, does your cruise work?

 

There is a little plastic plunger on the brake light switch. Push in the pedal and make sure it is pulled all of the way out so the pedal pushes it in all of the way. Over time, it can get pushed in by accident.

 

I just had the same problem on my D2. The brake light switch is a normally closed switch and when it fails the brake lights stay on.
There seems to have been a upgrade on the switch, the switch I received from AB was different and included a adapter to match the wiring plug.
I hope this helps.

 

Spike said "It could also be a bad brake light switch, does your cruise work?"

My cruise doesn't work and the brakes won't go off...is this a sure sign that it's a bad brake light switch? I can't see or feel anything wrong with the plunger. Anybody have any cost estimates to get this fixed?

 

http://www.roverparts.com/Parts/XKB000010G.cfm

10 min DIY.
Remove the old one, install the new one.