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Heater

SEAWOLF

MEMBER
1986 GMC JIMMY
4WD
AUTOMATIC
150,000 MILES

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?

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Tuesday, January 4th, 2011 AT 4:56 PM

2 Replies

DOCFIXIT

MECHANIC
18,828 POSTS

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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Tuesday, January 4th, 2011 AT 6:04 PM

SEAWOLF

MEMBER
2 POSTS

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

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Thursday, January 6th, 2011 AT 8:39 PM