Glow plug light immediately turns off after about half a sec

Hey everyone, first post here on this forum. I have a 95 super custom limited, and when I turn my ignition on to warm up the glow plugs, the light flashes for less than a second and turns off. I'm worried that my glow plugs aren't actually getting up to temperature as I think I have been having some rough starts in the mornings? It's my first diesel so I'm not terribly familiar with them. Has anyone ran into this issue before? Any help is greatly appreciated!

Some info here: https://www.youtube.com/watch?v=JN0SrqGyWgg&ab_channel=nathansharma87

Not sure why he says the older models, he means 95s - but it'll be worth trying the long cycle thing to see if it's the same as his 97. And if it isn't, you could try cycling the glow plugs without turning the engine over a few times to see if that helps?

I'll give that a watch after work! And thank you!

Do not worry the glow plugs are on for about 90 seconds if you turn on ignition but do not start engine you will hear relay click to off after 90 sec , I run on veg oil mix it starts well but runs rough after heaters turn off , perfect when up to temp.

My 98 Glow plug light only stays on for a second or two also, I stripped the plugs and timed them individually, they all took 15 seconds before going off. I now turn the ignition to position one, count to 14 using the clock, turn the ignition fully and the engine fires up immediately. If I go slightly over the 15 seconds it still fires up after a couple of turns.