I have a 2003 RAM 2500, Quad Cab, 4 X 4, 6 speed manual transmission with an unusal brake light problem. When depressing the brake pedal it takes 3 to 4 seconds before the brake lights actually illuminate. Initially I thought it might be the plunger on the brake light switch under the dash was sticking when the pedal was depressed. I ordered a new Mopar brake switch last week and followed the installation instructions to the letter and still have the same issue. The cruise control does disengage instantly upon depressing the brake pedal.

 

You might check the ground wires, does the third light come on or does it delay like the lights. Knowing that the cruise kicks out would suspect bad grounds,good luck.

 

No the back of cab high third light does not come on. I need to remove the camper shell which is probably "glued" to the pickup bed as it was installed 20+ years ago with I'm sure double sided sticky sealing tape. I will check the bulb, socket, ground and +12 VDC with a V-O-M this weekend. I hope it is one of those items. Thanks for the recommendation.

 

Have the same problem on my truck for years. At one time even suspected the trailer brake controller, so completely disconnect it. Have gone over everything I can think of, but no changes. Hope someone comes up with a solution.

 

you might have a fuse problem