ABS and Skid light on

I bought a new Leer cap, installed at the Leer dealer. On the way home the ABS light and the Skid lights both came on. I thought this is to much of a coincidence. when I shut the truck off and started it back up the lights stayed off for awhile but came back on, this happened each time I shut it off. Took it to my Toyota dealer who said it was the cap wiring, cap guy said we do a couple hundred of these a year, we will look at it. Have not made it back there yet but pulled the tail light and the wiring looks fine. pulled the fuses to the cap lights and the ABS/Skid light doesn't come on.

any one had any similar experience?
Thoughts or ideas?

 

What is a 'Leer cap'?

 

I learned it is best to not assume... I never heard a camper shell being called a cap... but the OP is in Vermont, and stuff from there doesn't surprise me!