Jim, (Bellevue, WA)
Since you did not indicate which solenoid was not switching, try the following. If the coach battery is not switching, check for 12-volt DC between the white and brown wires. If the problem is with the chassis solenoid, check for 12-volts between the gray and purple wires. If you have a nominal 12-volts present at these wires but the solenoid is not switching, then there is either a wiring or connection problem, or the solenoid itself is faulty. If you have no voltage at either of those two sets of wires, there is a problem with the switch or control board. If this is the case, turn off the switches and swap the wiring between the two switches, one at a time, being very careful not to mix up the wire positions. Hint: Label each one before removing them. Turn the switches back on and check to see whether the solenoid that wasn't working is functioning now. If so, you have a faulty switch. If the same solenoid still doesn't work, then the solenoid is faulty and needs to be replaced. Any other problem would likely indicate a problem with the control panel itself. Remember to return the switch wiring to their original positions.