ABS Modulator

The "clicking" noise that is apparent when keying the different trucks on is an ABS modulator valve actuating.  The modulator is an electro-pneumatic control valve that regulates input and output air for the brake canisters in ABS situations and restricts the wheels from locking up.

Part number: 550414 

Model: M-21

Replacement info:

P/N: 802363

Model: M-32