Pulled alternator, intermittent battery indicator lamp.

Initially, appearance of indicator lamp was accompanied by a change in needle position on the ammeter. After wiggling connector, drop in meter needle went away but indicator lamp still comes on intermittently.

Pulled alternator and removed voltage reg. Brushes are worn but smooth on wear surface. Commutator rings are grooved. When is it time to simply replace alternator versus replacing reg and brush set? How deep does the groove need to be to be "too deep"?

Truck has 159K, alternator is a Bosch unit so has been replaced once at least.

Noticed single wire connector had some blue/green corrosion on the terminal, wondering if that is part of the prob. Don't really want to have to splice in new connectors but can if necessary. Will try thoroughly cleaning the terminal first.

On other fronts, I ended up destroying the thermostat housing to remove it. One bolt head had rusted so the 8mm socket would not grab (or a previous incident had rounded it off). A 7mm was too small. I tried one of the sears "rounded bolt remover" tools but it would not grab the bolt head. A hammer and chisel along with a little Dremel work let me grab the offending bolt head with vise-grips. Used a crescent wrench on the vise grips to turn it and it came loose without too much effort. Have the housing mounting surface wire brushed clean, ready for a new housing.

This all started with changing the stat due to excessively slow warm up (hours).

I did get the blower resistor replaced and the resistor connector replaced so some progress is being made.

Also pulled the drive shaft, the inertial damper on the slip yoke came loose and was rattling around. Found a new one on ebay for a reasonable price and it is on the way. P/N F6ZZ-48341-BA. Any tips on lubing the slip yoke before reassembly would be welcome.

Thanks for any insight or comments. I am too verbose I think, sorry.