Comments:
1. do yourself a favor if you have the fan and shroud out and mod the shroud to make future access easier. See
viewtopic.php?f=98&t=64278&p=709322#p709322 and the links posted there.
2. if you have not already done so I'd recommend spending ca. $50 and replacing the weak OEM fan clutch with the Hayden 2905. You can also swap in the OEM gasser nylon fan or keep the metal one you have now. Either way the clutch is the important part.
3. X2 on bad alternator clutch eating serp belt tensioners. Red dust or at least a fair amount of it is a sign of a bad tensioner pulley and another sign is with the engine at idle look down the belt to the tensioner and if it's doing anything more than barely twitching the pulley is bad. In theory the pulley can be replaced if you can get it off for about $90 or you can get a lifetime warranty alternator from like AutoZone for ca. $150 or an OEM alternator from say IDparts for ca. $400. Whatever you do don't go cheap on the pulley or try a solid or "reactive" one.
4. light might not immediately show up when the belt goes but it should come on briefly when you first turn on the ignition or when you invoke the instrument cluster test by holding the trip odometer button while turning the ignition on. FYI if the LED bulb is out a dealer will try to sell you a new cluster for ca. $700 plus labor but if you or someone you know or have access to is a good hand with a solder gun the burned out LED can be replaced for a parts cost of like $2.00