Alternator Fault/Charging issues

Well, I knew this truck would be a project.... :-)

My 1997 4.0 just recently(with the start of the really cold weather here) started to flash the "alternator fault," light. Wanting to take the easy route out, I suspected the battery and replaced it with an optima red top. No change.

So, driving home yesterday(I think I may be driving on the battery), I noticed that the battery light comes on and goes out intermittently, as if the system is charging at times and not others.

So, I have a new alternator on order that should be here tomorrow, but I'm wondering if there's a ground wire or other wire that tends to be an issue? The light flickers on smooth roads, even at a stoplight, so I'm not confident I have a loose connection.

I'm trying to plan the assault ahead of time given the cold temps outside right now.

Simplest thing I can do I guess is throw a meter on the old alternator when the truck is running and see what it's doing. I'm also hearing a large relay clicking in the cab on the driver's side somewhere.

It hasn't stranded me yet, but I know I'm pushing my luck. Won't have time to work on it until tomorrow night.

If anyone has some experience or words of wisdom, let me know! :-)

Cheers! John