I have a 1994 plymouth voyager 239,000 miles 3.3. Liter engine.
1st My heater blows cold until I take off to drive then it gives a big loud clunk the the heat comes. And when I open the vent(when the heat is off) for cool air only heat blows out. And when I try to cut on the air and drive it clunk's and nothing but heat.@Nd My radio onlt plays Am the fm won't come in.3rd My door lock switch on the driver side use to lock but not unlock now it does not work at all.
1) The heater issue sounds like a vacuum issue. It sounds like you done have adequate vacuum to operate the vents at idle speed. I don't have the expertiese to tell you where to look or how to diagnose, but look in other forums for similar complaints and see what other people have to say.
2) There is nothing feeding the radio except 12 volts.
Buy a new radio.
3) Do I read this right, you have electric door locks and they used to work but not anymore?
Frist, do they make any sound when you try to lock/unlock them? If so you have a linkage problem. Open the door panel and look.
Second, if there is no sound, then check the fuses. Some cars have 2 fuse boxes. One is inside the car and one will be under the hood. If all fuses check out. Check you door switch.