Glow light remains dim after initial glow cycle

[2strokesmoke]

Hi guys,

I have some odd behavior from my glow plug light.
I Have an 82' Pickup with 1.6NA
During initial glow cycle, yellow dash light is bright (Has quick glow,with recently new glow plugs)
As engine warms up,yellow dash light comes on very dim and flickers somewhat.
Dash light continues to flicker and  remains dim,even as engine is fully warmed up and rad fan is cycling.
I had been running this truck,while restoring it,over the past several months. I didn't have the alternator in the truck (removed it and didn't put it back in right away,because I had a water pump to replace)
With the alternator removed,the dash light works normally.
Alternator seems to be charging good,although I didn't check voltage.
I did notice,that I seem to have an extra wire in the harness,near the alternator,but not sure where it goes.
It's a single black wire,about 12 gauge,with a female spade end connector,which is insulated.
My alternator has a 3 spade connector(which is hooked up),and there are 2 seperate  single male spade connections,which have no wires attached.
Perhaps the wire goes to one of those spade connectors ?
If so,which one ? It wasn't hooked up,when I bought the truck.
It was tie wrapped together with the wire connections ,for the  A/C Idle load compensating solenoids (which are both missing)
I hope this all makes sence ! LOL
Truck starts immediatly in 15 deg F and runs great.
It's just this glow light thing,has me puzzled.
I didn't want to randomly plug the black 12GA wire,into the alt,if it doesn't belong there.(don't want to kill an alt)
Thanks in advance, Mike

[rabbitman]

My GP light was dim/flickered when the body ground came loose.

[dennis]

Same here. I am still having ground issues also. My glow light will sometimes flicker with the music turned up.

[2strokesmoke]

Thanks guys !
I'll check into the grounds,this weekend.