Saab: 98 Saab 900s, defective alternator, radio cuts

Question
We recently replaced the alternator on our Saab and it seems when its wet out the check engine, check gear box, and abs dash warning lights come on.  Within 5 minutes of lights coming on the car slowly starts to lose power and eventually the radio cuts out, all lights start to become very dim and battery acts dead and clicks when trying to restart.  After sitting overnight, I go out and the car starts right up.   I was thinking moisture in the distributor cap or wires but don't know if that would explain warning lights coming on and lights slowly dimming.

Answer
John:
 Your observations are typical of a situation wherein the alternator is not recharging the battery. Either you got a defective alternator or there is a problem in the wiring connections in the charging system.
   The warning lights coming on are indicative of the battery being drained and NOT being recharged by the alternator. Overnight the "drained" battery recovers somewhat allowing the car to start.
    Jerry