Hello all,

I am driving a 1999 Discovery II with 137,000 miles. Do you guys know why when I press the brake paddle; the differential warning light comes on? It works like a brake light on the dashboard. This happened when I was driving home this afternoon. At the same evening I tried to take the car out, I was unable to shift down from park position. Can you guys tell me what’s wrong and how to fix this problem?

Thanks in advance.
O.C.

 

Wouldn't you have to have foot on brake to shift from park? If brake switch is not behaving as brake switch should, then the interlock might not work as expected. Do brake lights on the rear of the truck work as normal? And by differential light you mean the amber one, not the red brake light (would come on with low fluid and other delights). But I don't know where your wiring is shorted together..

Might want to check fuse 25 in the under dash fuse panel, it also deals with the shift interlock.

 

Are you referring to the CDL light, if so, have you ever engaged it before? If not then there is a short.

 

Here's the electrical diagram for some of that. The brake light switch and the interlock switch are both fed by the same fuse, so that might be a common place to start.

 

Hey, Savannah Buzz and Disco Mike, I wanted to give thanks to both of your advices. I just checked the brake lights and as predicted all three brake lights don’t light up when pressed. In addition, the #25 fuse was blown. I will check out the bulbs too.
Once again, Thanks.
O.C.