Onan generator only runs with switch held in

stan909 wrote:
Did the OP ever get his fixed ? I wonder.

Yes I got it repaired at an RV dealer that specializes in working on the older classic GMC RV's that also had Onan generators. Total cost was $500.90 for dropping the generator and VR - $260 of that was for the potted electronic voltage regulator (some are charging over $400 for just the VR). Since my generator repair I have diagnosed the same identical problem for two other Roadtrek owners - this costly repair does not appear to be that unusual at all and according to my mechanic the main board with the starter switch (mother board) and VR are common repairs for the Onan. I also discovered that it is possible for you to replace the VR without dropping the generator, but replacing the two VR screws will be very difficult (some replace just one). Another approach I have seen is mounting the new potted VR on the outside of the Onan case - this method would be a much easier repair and could easily save you $500, since some are asking $750 and up to drop the generator and replace the VR.