The quickest & easiest way to test a relay is by substitution. It can be bench tested using wires and a test lamp.
Swap the relay with another like relay.
A car relay is a remote control switch that controls electrical components. To see how you should test yours, check your owners manual. Simply swap it with another like relay.
use secondary injection test with pilots connected.
You can test a relay with and without a 9 volt battery. If you apply 9 volts to it and it's sufficient to turn on the relay, the NO switch will close and then have continuity with common. If you don't apply voltage, the NO switch will be open and not have continuity with common. You can use these continuity and resistance checks to test a relay to see if it works.
best way to test a relay is remove it from board, get a 9v square battery and touch the switching terminals on the relay, the relay should click if its working. You can then test resistance through the relay. You can also check the feed to the relay, if theres pwer to the switching terminals on the relay, chances are the switch it ok. If no voltage, switch or wiring.
In order to test the fuel pump relay, you must check that the two control circuit terminals on the relay are not connected, using an ohmmeter. You must also test the power circuit terminals on the relay, in the same way.
Swap it with known good one. Many circuits use the same relay, check the part number on the relay.
Typically, that problem would only be caused by a faulty horn relay or a damaged horn contact switch inside the steering column. A frayed wire that rubs on a metal part of the vehicle. Since the relay is the easiest part to test, remove the relay and replace it with a similar relay FOR TEST PURPOSES ONLY. If the horn works properly with a replacement relay, put the relay you used for testing back and purchase a new horn relay. If the test relay left the horn ON, you probably have a damaged horn contact switch, in which you will need to replace the faulty component.
Type your answer here... you don't... there is no way to test a faulty relay. Just buy a new relay and install it. If the problem is fixed, then the old relay was bad. If the problem still exists with the new relay installed, then the old relay is still good. Most auto parts stores are good for returning products, even electrical parts.
To test a relay, first disconnect it from the circuit and use a multimeter to check for continuity across the relay's contacts when the coil is energized. If the multimeter shows continuity when power is applied to the coil, the relay is functioning properly. You can also listen for a clicking sound when the relay is energized, indicating that the contacts are closing. If there's no continuity or the clicking sound is absent, the relay is likely defective.
Usually there is a relay that is the same next to it, just swap them and try it.