[Tony6275]

Have a 2020 Alterra 570, can't figure out which wire you use to hook up reverse lights. I have read some forums that said to use the red/yellow wire but with mine the test light comes on in park and reverse and goes off in the rest. Don't understand why I have 5 gears and 4 wires. Any help would be greatly appreciated..

 

[mikeexplorer]

This diagram is for the Alterra 500 but its probably the same. I hooked up reverse lights to an Alterra 400 which does not have a park selection so it was easy. As you can see here in Reverse L/W and Gr/G both will be closed and in Park only Gr/G will be closed (common)

Wire colors may be different for your machine

To have reverse lights come on only when selecting reverse take the L/W wire and connect that to a small relay, then tap into the Gr/G wire and connect that to the relay's NO contact. Then the common of the relay would connect to reverse lights.
This will only allow the common to be enabled if L/W AND Gr/G wires are closed.

Mike