Checking Glow Plug Relay

Checking Glow Plug Relay

With the glow plug relay installed, disconnect the wire from the stop solenoid on the fuel injection pump, and disconnect the engine temperature sensor. Check voltage between the glow plug wire, where it connects to the bus, and ground. Turn on the ignition and watch the glow plug warning light. When it goes out, there should still be voltage at the glow plug bus wire for approximately five seconds.

Next, turn off the ignition and ground the temperature sensor wire. When the starter is actuated, there should be voltage at the glow plugs bus wire. If the results of either test are not as specified, the relay is faulty and should be replaced.