Glow plug puzzle

[RayW]

Can someone please explain the following to me:

With the glow plug on my Otto glowing, if I disconnect either the positive or negative glow plug driver lead from the 12 volt battery then re-connect it, the plug does not light up again. If, on the other hand, with the driver leads connected to the battery, I disconnect either the positive lead from the plug, or the earth (ground) lead from the body of the engine, then reconnect, the plug starts to glow again.
I am sure there is a logical explanation, but I just can't figure out what it is at the moment. All suggestions gratefully received!

[Admiral_dk]

It must be the electronic part of the driver, that shuts down when you remove a lead and because it is still connected to the power it stays that way - and when you remove the power to the unit and reconnects it, it starts from scratch again (a bit like resetting the computer).

I believe the fact that it stays off even when connected to the power supply, is done to protect the battery from being discarded (destroying it) 

Best wishes

Per

[RayW]

Thanks Per. The driver seems to be working again correctly today. I am not sure why it was doing strange things yesterday.

Ray

[Noitoen]

Low battery cut out? Check out the voltage.