I have a six zone valve system (rainbird jarheads). Zone 1 does not shut off when zone 2 is on. From reading previous posts I suspect there is a problem with the #1 diaphram. 5 of the 6 are accessible in the green box and alll of those solenoids will click but I can't isolate which one is for zone 1. ( One of the wires from the controller goes underground beyond the green box,I guess to the 6th zone, instead of to the solenoids in the box. I plan to manually turn on zone 1 at the controller and with a volt meter find the #l solenoid. I can then check for a clog or replace the diaphram. Am I on the right track or is there any advice. Thanks.