Toyota Repair: 4Runner electrical, brake fluid reservoir, electrical failure

Question
I have a 97 4Runner SR5 5 speed. LED Clock went out then came back – a week later battery went dead. Store did test on electrical and came up with bad battery. New battery and three weeks later - the LED clock started dimming in and out and one time the cruise control could not be set.   Problem very inconsistent, but has only occurred when air conditioner is on.  The LED clock dimming and the cruise control occasionally going out is this a sign the alternator needs replacing - I don't want to get left on the side of the road – any other signs of electrical failure that should I look for.  Thanks for the info.  

Answer
Normally when the alternator is starting to have problems charging the battery the brake and battery warning light on the dash will turn on, I'm not sure what is going on with the clock or the cruise control, possibly a different issue.
Check the brake fluid reservoir, if it is too low the cruise control will not work, check the brake lights, check the fuses both under the hood and in the dash, lower left.
Have the alternator tested in the car under actual load conditions.