For some very electrically noisy automotive electrical environments, HGM recommends the addition of a surge suppressor the main wire harness on COMPUSHIFT Pro and COMPUSHIFT Sport controllers.
The procedure for installation is as follows:
Remove the top cover for the main connector by unlatching the clips on either side.
Once the top is removed, cut the cable tie at the bottom of the wire bundle to expose the second row of pins from the bottom, immediately above the red and black power and ground wires.
Remove the two plugs from pins immediately above the red and black wires as shown here:
Insert the provided surge suppressor, with the line on the same side as the red wire.
The pins will only go one way, as they each have a small tab on them that is toward the center of the plug.
Press the suppressor firmly into place so that it is fully seated. You will hear a click or double click when the pins are fully in place.
Fully inserted, the suppressor should look like this:
Re-bundle the wires together at the exit of the plug and tie them in place with the provided cable tie.
Trim the end of the tie flush and snap the cover back in place on the connector as shown.