Relays

What I've so far with relays is the first thing you ask yourself is "does the relay click"? If the relay doesn't work then you troubleshoot that part of the circuit and find out why. Relays have a solenoid and it's also a load itself. It should act like any other load and have approx 12 volts before the relay and close to zero after it. If you have less than 12 volts before the relay then you troubleshoot the power side of that part of the circuit. If you have more than zero after the solenoid than you troubleshoot the ground side after the relay. The main thing I took away from this was for step one ask myself "Does the relay work"?

Secondly I learned to tell the difference between HRVD's and opens. If it's measurable then it's an HRVD and if it's not then it's an open.