No Heat/no Air Con/no Defrost

1999 Chevy Astro. The Heat, Air Conditioning And Defrost Does Not Work. None Of The Fan Settings Work. Its Like The Whole Panel Is Shot. If I Leave The Fan On High, And Put The Heater On, And Drive Around, Sometimes It Will Kick In. But Lately No Such Luck. Basically None Of These Features Is Working At This Time. Any Ideas??? Loose Connection? Fuse?
Help!

I would check for both voltage and ground to the panel, in the correct places. You might have a blown fuse. If so, you will need to find the short. If you don't, the problem will recur. Ray

Don't think this is relevent because my fan motor worked at the time. My A/C stopped working last summer and I found that the hard plastic vaccume hoses broke. It still blew air but it was hot and humid. I bought black rubber hose that would slide over the factory plastic. Worked great but hard to get into the back of the engine. Now the heat is briefly blowing COLD but returns to hot. I suspect the same problem since I didn't replace all the plastic tube at the time.

Check your blower motor resistor. Look for the blower motor under the hood on the left by the A/C stuff. Near the blower motor ductwork you should find a wiring harness going into a rectangle plug (1/2"x3"). Pull this out. I have had part of this go bad on our 97 astro, we lost the lowest fan setting. If the whole thing is shot you could lose all fan settings. $40 dealer only item.

Had the same problem with our '93, and after trouble shooting endless miles of wire, finding nothing wrong, I changed the blower motor, and everything works just fine....

I just had the same intermittent problem with my '94 Safari. I replaced the blower with one from an '80 F-bird. Works fine except the little hose from the blower to the motor does't match.