Brake lights?

I recently purchased a 99 SE7 back in March.  Shortly after I purchased it I noticed the brake lights staying on.  So after looking into the problem, I decided to replace the stop light switch under the dash located on the brake pedal.  Worked fine.  Brake light went out and operated correctly.  However, they are now back on again after a month or two of having the switch in.  Just curious if anyone had any ideas concerning this issue?  What could be causeing this switch to fail?  Just a bad switch?  Any way to track down the problem? 
 
Thanks,
Wm

Low brake fluid will cause the brake light to come on.

I think he's talking about the brake lights at the rear of the truck.

look into the wiring.  I have never had the problem you're having in a disco but I had a similar one in my car along time ago.  Turned out to be a pinched wire at the brake light itself.  good luck!

Thanks for the input.  Yes, I am talking about the brake lights at the rear of the truck.  Sorry for the confusion.  Any additional comments?

Sorry, my bad!

check the plunger attached to the switch. Mine moves and I had to pull it out a little when I got mine. The lights were on all of the time.

Anybody have any input on the opposite happening? I have no brake lights. I have a 2002 SE7 II. All the fuses are good, the lights are good. What and where do I need to check to fix this?
 
 
`J

Check and replace your brake light located on the brake pedal arm.
Mike

Do you mean the brake light switch?  A little black "L" shaped piece with an arm the moves in and out?