automotive electrical relay tester

[Michael C Henry]

You guys have come through so many time before. I'm working on a lot of trucks that have many of those square plug in relays like the ones I used on my replica. One truck has 5 different part numbered relays and about 24 relays total 12 ad 24 Volt. A coworker has a home made tester that iIve used a lot lately. His tester is a 2 by 2 inch metal enclosure about 4 or 5 inches long. The tester has a 5 blade electrical socket on top, two lights, one push button switch, and it appears to have a self resetting breaker inside the enclosure. Two wires ,one positive and another negative with medium electrical clamps for attaching to a battery terminal or slave recptical for a power source. A good 5 blade relay SPDT would test like this, plug in relay connect power and one light would illuminate, push the button and the first light goes out and the second light illuminaes. 4 blade relays are SPST and would only illuminate the second light when button was pressed. 12 and 24 Volt depending on which relay being tested.
Is there an automotive electrical relay tester produced for comsumers like myself?