I bought an 86 f250 yesterday and need to figure out if my gp's are working or at least trying to work.When I turn the key to start the glow plugs the gp light flashes briefly but only for maybe 2 seconds my questions
1 , when working properly does the gp light stay on solid while they are warming and if so for how long? Or does the light flash on and off while they are warming?

Do I need to depress the throttle at all for cold morning statrts?

The ign switch is VERY hard to turn when it's cold out, any how to's on replacing it, wondering if it's the actual column switch or the electrical switch at the bottom of the column, seems like this was a common issue with these trucks?
truck does not have tilt steering , I read where switch replacement was easy on the tilt steering column.

Thanks for any help...

 

The light should stay on for about 5-10 seconds then shut off. And yeah do half throttle.

 

The rod that actuated the switch on mine wore out the switch and would make it hard to turn to start. I put in a pushbutton and solved it.