Checking Wiring

Testing & Repairing Glow Plug System Circuits - Checking Wiring


To check the continuity of the wiring, remove the glow plug relay from the relay panel. There should be continuity (zero ohms resistance) between the fuse/relay panel socket for terminal 87 and the bus bar connection at glow plug No. 1. If not, then there is a break or short in the wire. On Jettas, check the in-line fuse which is in the wire to the bus bar.

Check for continuity between the fuse/relay panel socket for terminal T and ground. There should be continuity at engine coolant temperature below 122°F (50°C), and no continuity when coolant temperature is above that mark. If not, either the temperature sensor or the wire from the temperature sensor is faulty.