Hunter Pro-C zone 4 not working
I have a Hunter Pro-C, expanded with modules to have 12 zones. 1-3 are wired but those zones never had the heads installed so they have never been run. 4-12 started out running fine. 4 since stopped running. Replaced solenoid, no luck, so investigated the controller. Using a multimeter, when zone 4 activates, it looks like power goes to zones 1-4 (don't have the exact reading). On the other zones 5-12, when they activate only those zones seem to have power. So even on the expansion module with 4, zones 5 and 6 work properly.
Any ideas? Is the main controller just short circuiting those zones? Anything to try?