Not Sure mine doesnt seem to have one 2004 HDI but the handbook shows there is.
I had this problem and it was broken solder on the timing circuit board for the glow plugs
The glow plug relay unit is attached to the battery housing on the 405
you need to check your glow plug relay it is most likely going out you can jumper it to see if the glow plug light will come back on to start engine
under the air filter box
Why are you illiterate.
The glow plug relay is the 'black box' unit fixed to the side of the coolant header tank (LHS engine bay as you look at it).
The glow-plugs are located under the valve covers. There is a single wire that comes out of each injector harness that powers each glow-plug. Disconnect the single wire from the glow plug. Connect the gator clip of a test light to a positive and probe the glow plug terminal with the test light. If test light does not come on the glow plug is bad.
This test will determine what glow plugs are working. ( It will not determine a partially burnt plug ). Disconnect the glow plug wires at the plugs .( You must unplug all of them for this test to work ) Connect a test light to the positive terminal of the battery. Touch the electrical connector at the end of the glow plug with the test light. If the light goes on the glow plug is working. Make sure you touch only the electrical connector on the plug. If you touch any other part (metal) of the plug the test light will light giving you a false reading.
as far as i know C3's don't have a glow plug light or only use it when it is very cold i.e below freezing
You can actually check the glow plugs with a common test light unplug the wire feeding power to the glow plug and connect the alligater clip the hot post of your battery and touch the tip of the glow plug with tester if the light comes on the plug is good also if you have 3 of 4 burned out the glow plug system will not function properly
From memory It's located very near the battery on on the bulkhead Mike 2
right next to the batter, should be attached at the back end of it