I have a problem with my 2000 F-150(V8). I bought it used and 2 weeks after I got it I started having problems with the fan blower. Under acceleration it flips from panel to defrost and when I let off the gas it comes back to panel. When the A/C is on it causes the compressor to shut off. I had a mech look at it and said there was no vacuum leaks. I read another furum where someone else had this problem but couldn't understand what the fix was. I hope someone can elaberate on this solution.

 

I know that this is of no help to you at all, but I do have the same problem on my '97. On another website, it was suggested to someone else that has our problem to check for a leaking vacuum storage can, but all I have been able to find is the drier, and this shouldn't have anything to do with it, you think? There is also mention of a check valve that keeps this container at vacuum. I am going to look around more (since I am at work and I can't really investigate it thourghly yet) and see what I can come up with...

Until then, good luck, and hopefully someone can help me, the wannabe mechanic...

Cheers
Bill