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Author Topic: 1977 GMC High Sierra cab blower  (Read 1631 times)

Offline 1977gmctruck

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1977 GMC High Sierra cab blower
« on: May 04, 2021, 05:35:15 PM »
I have a 1977 gmc high Sierra and am wondering does the cab fan always stay on? If so has anybody
Done anything to make it so you can turn it completely off? Thanks
« Last Edit: May 04, 2021, 05:59:18 PM by 1977gmctruck »
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Offline Rapid Roy

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Re: 1978 GMC High Sierra cab blower
« Reply #1 on: May 04, 2021, 05:56:13 PM »
Check out this thread post #4. If yours is setup like mine it will work.

http://forum.73-87chevytrucks.com/smforum/index.php?topic=37913.msg316928#msg316928
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Online bd

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Re: 1977 GMC High Sierra cab blower
« Reply #2 on: May 04, 2021, 08:15:24 PM »
The fan is engineered to operate at low speed continuously to help dry out condensation that collects in the A/C ducts in an effort to prevent the formation of stinky mildew and mold.  Unless you reside in a truly arid environment, defeating low fan is not a good idea.
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Rich
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Offline 1977gmctruck

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Re: 1977 GMC High Sierra cab blower
« Reply #3 on: May 04, 2021, 09:05:20 PM »
This truck in a non AC truck and live in Minnesota also. Just trying to figure out a seat to have it off on the warm summer days. Thanks
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Offline Geezer77GMC

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Re: 1977 GMC High Sierra cab blower
« Reply #4 on: May 07, 2021, 08:02:52 AM »
My 77 K25 non-ac has a 4 position blower switch, HI, MED, LO or OFF can be selected. Face plate labeled OFF at bottom & HIGH at the top with a 4-blade fan graphic to the right of the switch slot in the face plate. Have had this truck for 43 years, pretty sure it's the original configuration. Yes I've seen trucks with the 3-position, don't know the reason for the difference.
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Offline VileZambonie

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Re: 1977 GMC High Sierra cab blower
« Reply #5 on: May 07, 2021, 04:19:15 PM »
They had 3 and 4 speed position switches without AC, so you need to look at your original configuration to determine which setup you had. I believe the main difference was with or without the fresh air vents
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Offline Geezer77GMC

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Re: 1977 GMC High Sierra cab blower
« Reply #6 on: May 07, 2021, 08:31:03 PM »
Probably correct , my non-AC vehicle has floor vents on both sides and came with a rear sliding window.
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