Can someone fully explain these? I am quite sure the retarder is the exhaust brake, but what is the ICC, and do they work together?

Thanks, and forgive my ignorance. I have owned two Adventurer's, but this is my first step up to the DP's, and we are loving it.

The ICC switch is for flashing the parking/clearance lights.

It's used when passing another vehicle to thank them when they flash their headlights to let you know it's safe to move in front of them.

It stands for the old Interstate Commerce Commission.

Thanks.....I had no idea. I appreciate the insight.