Hello,

The Volvo neutral safety switch incorporates several functions into one.

1) Electrical connection for the starter (so the car starts only in Park or Neutral)
2) Reverse (back-up) light connection.
3) Tells the engine ECU to increase idle speed when the gear is engaged into Drive (to counteract increased load when transmission is engaged)

When the reverse lights connections fail the starter connections may fail too in the future. Both are in the same switch so both gets the same wear & tear. You may try to start in Neutral if the position in Park fails later on.

I've tried to dismantle it open (yes it could be done) and repair its contacts last time, but my no start problem resurfaces again (at inconvenient time too). And I've got low idle problem with engine shaking when in Drive during stop-go traffic.

In the end its easier to just replace the switch with new and be done with it. This switch has a long life span - about 20 years. Rest assured it is a worthwhile investment.

Regards,
Amarin.