glow plug timer

hi fellas i have a little problem my glow plugs only power up for about 3 seconds , any ideas why this is so ,cheers

Start by checking the glow plug fuses and continuity of each glow plug.

It's more then likely a problem with the engine temperature sensor, make sure it is still connected and the wires aren't broken at the sender.

Have you had water inside the vehicle recently?

hi mate thanks for your reply haven't had any water in the cab, have checked fuses and glow plugs all ok, and the temp sender is that the one on the water neck , and could you tell me what the brass fitting does on the inlet manifold has two heat shielded wires coming off it ,cheers

The temp sender for the glow plug circuit is the one with two wires the other one beside it with the single wire is for the temperature gauge.

The fitting in the inlet manifold with the two wires is a resistor for stage two of the glow plugs.

Stage one the glow plugs get full battery voltage.

Stage two the voltage to the glow plugs is reduced by the resistor.

The resistor is mounted in the manifold to help keep it cool (it can get very hot) and I also think to help heat up the air in the inlet manifold.