It is easier to remove the solenoids for a thorough check. This serves two purposes as you have an opportunity to clean and ensure all electrical connections are tight when reassembling.
- Firstly check that the contacts inside the solenoid are not stuck, connect a multimeter on the ohms setting between the two large [usually copper] studs. There should be an open circuit i.e. infinite resistance reading.
- Next connect a jumper wire from one of the small terminals to the –ve terminal of your battery. Connect another wire from the other small terminal to the +ve terminal of your battery. The solenoid should click indicating the contacts have met and the solenoid is now “live”.
- Connect the multimeter to the two large studs while the solenoid is “live” and the resistance should read zero [0] Ohms.
We recommend that you replace solenoids in pairs as it is likely that as one is faulty, the other is not that far away from failing. You can then keep the old still functioning solenoid as a spare.