How do I test glow plugs?
How do I test glow plugs? Testing Glow Plugs in the Engine Grab a multimeter. Set your multimeter to ohms. Find resistance value of your multimeter. Test the voltage of the battery. Locate the glow plugs. Remove the caps or connectors to the glow plugs. Clip the multimeter’s negative lead to a ground point in the engine. How long should glow plug relay stay on? The glow plug relay should stay on for up to two minutes depending on temperature. The wait to start light is not an accurate gauge of weather or not the GPR is on. You can...