Foton 254: Ignition switch and glow plug question

[D0TC0M]

I'm trying to fix all the wiring from the previous owner and I'm at the ignition switch. The ignition switch has 5 wires connected to it. White(large), White/Black(small), Red(large),Red/Black(small), and Red/White(small).

The ignition switch has 5 positions,

OFF
ACC
ON
H(spring return)
ST(spring return)

In the schematic it shows only 4 wires being used. It seems the H wire isn't being used.

The Accessories are connected to the ACC wires
Glow plugs are connected to the ON teminal
Starter relay is connected to the ST terminal.

When turning the ignition switch pass the ON position the H terminal becomes live first and then if you keep turning the key to the end of its travel the ST terminal becomes live.
Is it normal for the glow plugs which are connected to the ON terminal be all the time even after the engine is running? I would have thought that the glow plugs would be connected to the the H terminal and when you would turn the key you would turn and hold the key in H position than once the glow plugs are given a chance to heat up you would turn the key to ST (start) position to start the tractor, Once started you would release the key to the ON position and the starter and glow plugs would turn off. Is this not normal operation or should the glow plugs always have power going to them?

 

[doxford jim]

The glow plugs are powered for just a short time. After the engine is started and running (when the key returns to ON) the glow plugs should be off.
Only on other vehicles - trucks, pickups etc., do the plugs stay on for a short time and are then switched off by a timer or temperature sensor (on my F250 the glow plugs cycle until a certain temperature is achieved, then they are switched).
I very much doubt that your tractor glow plugs will automatically cycle - they appear to be basically, manually operated. From what you say in your post, the glow plugs are powered at H and ST - that sounds about right. Turn the key to H and hold for say 15 secs. to give the plugs time to heat up and then turn the switch to start. Once the engine is running the key is returned to ON and the power to the glow plugs will/should be OFF.

 

[D0TC0M]

ok after tracing out the wires. Friggin chinese can't use the same color wire from start to finish. The glow plugs are connected to the H terminal of the switch which is the first contact to close as you turn it pass the ON position. You can hold it in this position to let the glow plugs warm up then continue turning the ignition switch to the start position to engage the starter.

The ignition switch is wired as follows,

OFF -OFF
ACC - Not used
ON - Accessories Relay
H(spring return) - Glow Plugs Relay
ST(spring return) - Starter Relay

It now makes more sense is seems to be properly wired.

 

[doxford jim]

yep, you will get pretty good with Chinglese by the time you get it all sorted out:cool2: and you will be able to help others in a similar situation as yerself.