Friday October 4, 2024
Electrical Troubleshooting (Firewall Forward)
1.5 Hours

I ordered and received a 12 volt 25-30 amp switching power supply to use to power the plane while I wire it up. So I hooked the battery wires up to it and turned it on to test the contactors. As soon as I enabled the battery contactor by placing a screw driver to ground from the switch terminal, I heard it snap on, but the solenoid in the starter also switched on and started cycling.

I spent quite a while trying to figure out what was going on. I wired up a switch to both contactors so I could turn them on and off individually. It turned out that any time the battery contactor was switched on, power was being applied through my starter contactor to the starter itself. Switching the starter contactor on and off made no difference.

I finally figured out that I must have rotated the lugs on the starter contactor when I attached the big starter wire to it. According to a note on the Van's web store for the starter contactor, if you do that, it can cause the starter to act just how mine was (i.e. always be on). There's no way to really fix it once it rotates, so I ordered a new one.

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