on my 73 elcamino on the a/c panel the high setting won't work for the blower motor. low and med work but no high. any sugestions????

The high speed fan has a 30 amp fluse.
The fluse is located under the hood on the firewall on the left side. The wire and fluse is laying on the brake power booster.

On the fire wall there is a little box with either one or two plugs going to it. Look on the bottom of the box where the plugs go and there should be numbers on it. Numbers like 1 2 3 4 or in a different sequence. Go to the junk yard and get one just like it and replace it. This is the different settings for the speed of the blower. I had the same problem and changed everything and it ended up to be that little box. It is half the size of a candy bar. Also check to see if it is bolted goo to the firewall. If it isnt grounded it might not make good connection. Good Luck