Continued from previous page

7. Setting of the sensor airgap.
Locate the sensor in its mounting bracket and rotate the propshaft such that the bolthead is adjacent to the sensing face.  
Adjust the airgap to approx 7-8mm.
Turn on the ignition.
Slowly reduce the airgap by rotating the appropriate mounting nut until the led illuminates.
Further reduce the airgap by 1 turn of the mounting nut.
Rotate the propshaft and check that the led illuminates and goes off each time a bolthead passes the sensor face.
Switch off the ignition.

8. Fault finding.
To check if the sender is operating correctly, measure the voltage on the sensor black wire when the propshaft is being rotated slowly with the ignition on.  The voltage should switch between 0 volts and 12 volts as the propshaft rotates

For instructions on calibrating and installing your speedometer to match the signal being generated by this sensor please see the following links:

http://www.caigauge.com/page27.html - for older design (dip-switches through rear case)
http://www.caigauge.com/page28.html - for current design (set via trip switch)