01 Classic abs light

Anyone know the location of ecu diagnostic button for blink codes? If any

 

Might help someone. Located under bunk behind passenger seat . Wabco Meritor switch for blink codes abs light on dash flashes code.

 

Updeat -might help someone in future. Fixed trailer abs light w/ new power cord to ECU $75.00 Got it working. Light stayed on.Had 1 bad sensor wire. Replaced both sensors( first) and then both extension wires $160.00. Wabco website has good info on flash codes.Trailer wheel Codes are opposite each other depending on valve type. Truck- had to replace light itself on dash. Light stayed on. Used button under bunk. Replaced sensor right wheel. Still on . Found broken wire in rear harness to valve and sensors. Replaced rear harness $155.00. Code went away and replaced by right steer sensor gap too wide. Pushed sensor in . Light off. I broke sensor bracket on rear drive. Fragile aluminum. Two 7/8 bolts hold it on. Only $5.00 at Dealer. Bought an extra gonna change out other side w/ new sensor too as PM next brake job.