Practice question

For Michigan CDL air-brake testing, how do you test the trailer service (signal) brake during pre-trip?

Apply the foot brake only
Charge the trailer system, release tractor and trailer parking brakes, then apply the foot valve — confirm the trailer brakes apply and that air pressure does not drop excessively
Pull the parking brake out
Drain the wet tank only

Answer: B — Charge the trailer system, release tractor and trailer parking brakes, then apply the foot valve — confirm the trailer brakes apply and that air pressure does not drop excessively

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