Checking relays is relatively easy, but this device makes it even easier and faster. Just be sure the 12-volt battery you are using as a power source is fully charged and has at least 12.8 volts in it.

This saved me a lot of trouble shooting.Relays last 50,000 to 100,000 miles.I had a no spark no crank problem this tool identified 2 bad relays.

I think it does what it's supposed to do. I tested a half dozen relays and they all tested as good. The green light flashed 10 times then stayed on steady on the 11th flash on the 5 pin relays. It would be nice to know if each flash means it is testing a different function or is just flashing to keep you entertained while it's doing its thing. I guess it's just a Pass/Fail tester. A pair of relay puller pliers is a handy thing to have to easily pull tightly packed relays and mini fuses.

This is a huge time saver. I was unaware such a tool exists. Rather than fumbling around clipping a power and ground supply onto the coil side and then resistance checking the switch side, you select 4-pin or 5-pin on the unit, plug the relay into the applicable slot in the board, and simply press the button. It activates the coil and checks continuity on the switch side 10 times in a row. If it detects a failure even 1/10 times, you get a red light to indicate bad relay. If it works on every actuation, you get a green light indicating good relay. This method of testing is more accurate than the old fashioned way because these failures are often intermittent and you might not catch the problem on 1 test.

very easy to use. I consider it very fragile as it is light weight and all plastic but does the job.a must have for your tool box if you do any mechanical work for a very low price