The Electronic Specialties Relay Fuse Buddy, No. 316, is a diagnostic tool that features an on/off relay bypass switch and live current meter. The tester will normally connect at the fuse panel, where most vehicle relays are found. Relay Fuse Buddy has many applications and can assist in determining whether the problem is the relay, the circuit, or the component. It can be used to turn on/off DC motors, fuel injectors and fuel pumps, for example. Adapters are included for six of the most common types of relays, providing wide test coverage. An amp probe is not required.