My friend is trying to figure out an issue on his wife's new to her 08 500 EFI.

He has a service manual, looking for help on where to start...

When you back up, it quits, but if you hold the reverse over ride in, it backs up fine, full power and AWD.

Also, the needle on the cluster goes from 0 to max then back to zero in a constant cycle.

Would this be a ground issue?

 

Reverse limiter is incorporated into the speedometer. Look at the wiring diagram,shows a green/orange leading from the over ride button to the speedo harness connector. Problem could be in the connector or its wiring or even in the speedo head itself. There's several posts on bypassing the over ride button for 2003 models and later,but don't know if that would solve the problem or not on the 2008.
"The problem with the new style, is that the function button for the Speedo is combined with the override button and it is not as straight forward as the old style Speedo. Doing it this way everything works as it should exactly the way it did before the mod.
You will need to purchase a standard 4 pin, 12v relay, 4 pieces of 16 gauge wire about 8″ long, 4 female crimp on spade connectors (for connection of wires to relay), and 4 wire splice connectors. (they are usually blue and you simply insert the wires and squeeze with pliers, then fold back the protective locking cover)

Open the pod and locate the wiring harness coming from the Speedo.

Relay terminal #30 connect to Polaris brown wire
Relay terminal #87 connect to Polaris wire gray/orange
Relay terminal #86 connect to Polaris wire red/white
Relay terminal #85 connect to Polaris wire purple.

Use dielectric grease at all electrical connections to prevent corrosion in the long run or even better, liquid tape.

To test, simply put it in reverse with the engine running, if the Speedo flashes the word “SLOW” (just like it did before the mod, when you pressed the override button) you did everything correct."

 

Thanks OPT! Will keep you updated.