Explorer electronics

I have a 96 Ford Explorer that I’d like to drive for another 1-1/2 to 2 years before taking on a new payment. (150K miles, no major problems, before now.) However, it’s been doing some wierd things lately. Namely:

1. The “Door Ajar” light will not shut off, despite repeated, vigorous slamming of the doors.

2. The interior lights will sometimes not go off, or sometimes they will go off, only to come back on later. I got tired of dealing with dead battery problems, so my “solution”, for now, is to pull the appropriate fuse to ensure they stay off. While this is a hassle, it’s less of a hassle than asking strangers for a jump every day.

3. My car alarm has, on multiple ocassions, started going off for no apparent reason. “Solution”: stop locking the doors.

I’ve just put almost $1,000 in the car in the last month (tires, new heater blower motor, serpentine belt and tensioner pulley . . .and battery, of course)so I’m not wanting to give up too easily, but I don’t want to nickel & dime myself to death chasing problems, either. Could this all be traced to a door sensor? If so, how “worth it” would it be to replace? Also, I had a buddy suggest it could all be traced to a bad alternator, is that possible?

Bottom line–worth fixing, or time to bite the bullet?

All three problems are likely related to a bad switch inside one of the door latches.