Glow Plugs
WARNING: This page is about a different car, the 1983 Volkswagen Vanagon, 1983 Volkswagen Rabbit, 1983 Volkswagen Quantum, 1983 Volkswagen Pickup, and 1983 Volkswagen Jetta. However, it is still accessible from the selected car via links, so may be relevant.
During cold starts, glow plugs are used to preheat swirl chambers. When current is applied, glow plugs become red hot. A temperature sensor connected to a time circuit in glow plug relay controls pre-heating time.
To start a cold engine on all models, pull out cold start knob to left of steering column. Turn ignition switch to glow plug position (No. 2). When light goes out, crank the engine. At below freezing temperatures, depress accelerator pedal while cranking. About 2 minutes after engine starts, push cold start knob in fully.