How To Test and Diagnose Relays and Wiring [4 & 5 Pin]
Published at : 23 Dec 2025
Relays and wiring can be a real pain, and the whole process of testing and diagnosing can be daunting. If you simplify it and break it into pieces, it's not all that bad. We show you some simple ways to diagnose a relay and confirm whether it's alive or dead. You'll definitely want a multi-meter, some jumper wires, and a 12-volt source. Let's get started.