It sounds like my problem.
My blower would not work if the weather is cold and it only worked when it was a bit warm outside. Replaced the thermo, the monovalve and still no go. Finally found out that the ignition switch was the problem. Since the connecters on the switch are made of metal (of course) then once cold the connecters will not make contact and the blower did not have any juice. And once warm temp is in the air the metal will expand therefore making a connection and I have a blower that work.
Here is a way to check that, you need a test light. Open the fuse box when the blower is not working. Remove the fuse for the blower. And then make contact on the terminals of the fuse holder to see if the light works, if the light does not come on from either side of the fuse terminals you are not getting juice to the blower or the blower relay. Try the light from another fuse just to make sure it works.
Good luck and be careful not to short anything out.
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