heater

1986 GMC JIMMY
150,000 MILES • 4WD • AUTOMATIC
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SEAWOLF
  • MEMBER
  • 2 POSTS
I have a 1986 k5 blazer 305 ,recently i installed a 350 out of a 78 gmc pickup,since then the heater will not switch to defrost or vent,have lots of heat and fan works fine Did i miss a vacum hose?.I see a 1/2 inch one near the firewall,seems to enter the cab below the fuse box,its not connected to any thing???
Jan 4, 2011 at 4:56 PM
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DOCFIXIT
  • ✓ASE Certified Mechanic
  • 18,828 POSTS
  • ASE Certified Mechanic
Yes vacuum is problem without heater controls go to default. That hose off could be the one but see diagram hose will come from vaccum tank and should have a check valve. Maybe still on old engine
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Jan 4, 2011 at 6:04 PM
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SEAWOLF
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Found hose(more like a small tube)hooked it up works fine thanks.I skipped by it several times ,thought it was an electrical(push on)connection,Thanks foe you're help
Jan 6, 2011 at 8:39 PM
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