Two Sprinkler Zones Interlocked: Controller Terminal Fault Confirmed by Wire Swapping

Zones 2&3 run together on an 8-zone system. Wire-swapping tests at controller and solenoid prove controller terminals 2&3 are internally bridged.

Test Results Decoded

• Zone 3 wire on term 2 → both run
• Zone 3 wire on term 3 → neither runs
• Zone 2 wire on term 2 → neither runs
• Zone 2 wire on term 3 → both run
• At solenoid: wires swapped → zones follow wires, not terminals

Conclusion

Controller output drivers for stations 2&3 are shorted together. Valves and field wires are good.

Fix

1. Try cleaning controller board (canned air, soft brush).
2. If no change → replace controller.

Your systematic testing nailed it. Controller is the culprit.