I'm confused here then! (That said it doesn;t take much!!)
There is a wire from the resistor on the bulkhead which then connects to the No4 glow plug, there is then another wire from No4 connected to No3. No3 is then connected to No2 and then finally No2 is connected to No1, this is where the wiring stops.
Do the plugs self earth or something then or should No1 glow plug be earthed???
Thks