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Chevy S10 pickup HVAC wiring problem fan, vaccum problem dampers

1992 chevy pickup S-10 4.3L,
The Heater / A/C fan would come on late for about 1 week. Now it hasen't come on at all for the last 3 days. 12 volts is detected on 2 terminals of a 5 terminal wireing harnis conector or plug that goes to the relay (under the hood). The relay was replaced new about 6 weeks ago because the fan wouldn't work on high speed but did on the 3 slower speeds. Also 1 of the switches in the dash that changes a/c, vent, heat, defrost etc.(the 1 on the right) was replaced because I was told that that was were the power for the whole system came from (also some one had replaced a broke one for the original one befor I bought the truck.
Question 1:
If I unplug the relay and the fan motor wireing harnes conectors, Can I put a Jumper wire from 1 of the 12 volt terminals (not the big purpel wire fed terminal but the smaler yelow or blue wire fed terminal) to 1 of the terminals coming out of the fan housing to see if the fan motor is OK?
Question 2: If this is a safe way to check out the fan motor and I crimp wire lugs on each end of the jumper that I use. Can I leave the jumper on untill I can get a new relay (assuming the relay is the problem) so I will have some heat till I can get another new relay?
Question 3:
If this can be done, is there a terminal on the fan housing that I shouldn't put 12 volts to or do thay all take 12 volts?

My dampers in the duct work are stoped in the bilevel position (defrost and floor) witch is not a big problem right now in the cold weather, But I had a mecanic replaced a small round black plastic vacum valve in the dash that was causing the system lose vaccum, making it to weak to move the dampers. I assume this because when I pressed the valve with my thumb and 1st finger pinching it together, the leak stoped temiraely until I moved the assmbley to put it back in the dash. During that time the dampers would work in all positions. Now that the mecanic has replaced the valve you could hear another vaccum leak some were deaper in the dash and the dampers didn't work after the valve was replaced anyway. The mechanic unhooked something to stop the nose of the leak and when he gets time to work on it he said he would have to tear out the dash to get to the stuck dampers to fix them. He is a friend and works on vehicals all day. I didn't want to question him because he knows more about it than I do, but if the dampers were working with the old valve when I pinched it together, and temporarly stoped the vaccum leak in the valve.
Qustion 4:
What could have happend to the system (ruber vaccum tubes in dash or what ever else is in there) posibly while the valve was being replaced that would make replacing the valve not fix the problem of the dampers lack of vaccum keeping them from changing position as they did befor when the leak was temparaly stoped. That wouldn't requre tearing out the dash to fix?
Note: There is a small amount of draft in the duct work so you can fill hot and cold air. Those parts of the HVAC work very well.
sorry about my bad spelling and gramer.
Thank you for any help you have to offer. Joe

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Testimonial: "I fixed the problem - the terminal at the brown wire was corroded - after cleaning and recrimping - everything works - thanks for the heads up"


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