Hi I just bought a 98 5.2L Durango I have 2 problems with it. First is the parking brake light is on and I don't know what it could be I know that the parking brake is not on is this a common problem? Second is when I am driving at 100kmh the speedometer moves down to 60kmh and stays there for a bit then jumps back up and then back down for the whole drive. Anyone know what this could be?

 

if the abs light is also on i would start be replacing the speed sensors, one on top of the rear differential and one on the output shaft of the transmission, on the drivers side of the vehicle.

otherwise i would suggest pulling up on the e-brake pedal when you release it to make sure its returning all the way, could also check the switch at the e-brake pedal too a dvm should do the trick

 

also check your brake fluid.. if it is really low that can trigger the brake light to come on...

 

Sounds like you need to replace your rear ABS sensor on top of the differential.