Rusty I checked the voltage to the relay 12.30 volts. Out of the relay 12.20 and at the glow plug terminal 12.00 volts. The resistance on the glow plugs on the car are coming in at 56.7, 65.8 and one at 17,500 ohms. The 17,500 ohm one had half the glow plug mi... Login to read more.