Hey guys I have a 2003 Mustang. Lately I've been having issues with the battery; or so I thought. On random occasions my car wouldn't start, I would attempt to jump it off but no luck. But when I moved the wires it cranked. Now it's happening again, of course I wiggled the wires but it didn't work this time. I tested the battery with my voltmeter and it is charged. When I opened my door I heard a clicking noise coming from under the dash. When I got down there to check it seems the clicking is coming from or near the fuse box. Could this be an ignition relay or switch? Or bad wiring. Also I have no aftermarket electrical items except radio. Thanks

 

In my experience the clicking under the dash is usually a relay opening and closing the circuit because the relay has failed. I would swap out all the relays so that way, you don't continue to have issues because once one relay goes bad that means the clock has run out on the rest of them so it's just a matter of time, especially if they're 16 years old now.