How do you test a glow plug without a meter? Maybe take one out at a time and turn the ignition to see if they get hot? Would that be a good test? Eric

Use a test light. Unhook the glow plug wire, connect one lead of the test light to the connector on the glow plug and connect the other wire on the test light to the positive (+) side of the battery. If the light lights, you have continuity and the glow plug should be good. Test the brightness of the light by grounding it first. Since the resistance of a glow plug is very low (about 1 ohm) the light should be almost full brightness when testing the plug.