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WILL HEAT WORK WITH NO VACUUM

  • Thread starter Thread starter Foxbodychris90
  • Start date Start date Dec 14, 2024
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    heater hvac vacuum
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Foxbodychris90

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May 9, 2024
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Dec 14, 2024
#1
  • Dec 14, 2024
  • #1
I know it will be defaulted to the defroster vents but will the air coming out of the defrost vents get warm on a 1990 if there is no vacuum connected to the HVAC controls? if not what size hose connects to the rear of the HVAC controls to run out to the firewall?

thanks
 

TOOLOW91

If you're the village idiot what's that make me?
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#2
  • Dec 15, 2024
  • #2
As long as the blend door cable is hooked up it will get hot with the door on heat

Line is 1/8 inch I think
 
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Mustang5L5

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#3
  • Dec 17, 2024
  • #3
Blend door is cable actuated, so as long as you can move that and the door is functional, it will blow heat.

The line to the HVAC controls also contains a vac canister and check valve. Without these, when you go WOT and lose vacuum, the HVAC will default to defrost/floor and remain there until vac is restored

 
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Foxbodychris90

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May 9, 2024
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Dec 17, 2024
#4
  • Dec 17, 2024
  • #4
TOOLOW91 said:
As long as the blend door cable is hooked up it will get hot with the door on heat

Line is 1/8 inch I think
Click to expand...
so long as i did not disconnect any cables in dash ill be safe with no vacuum from what i understand?
 
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Foxbodychris90

Member
May 9, 2024
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Dec 17, 2024
#5
  • Dec 17, 2024
  • #5
Mustang5L5 said:
Mustang5L5 said:
Blend door is cable actuated, so as long as you can move that and the door is functional, it will blow heat.

The line to the HVAC controls also contains a vac canister and check valve. Without these, when you go WOT and lose vacuum, the HVAC will default to defrost/floor and remain there until vac is restored

Click to expand...
what about at highway speeds not accelerating?
Blend door is cable actuated, so as long as you can move that and the door is functional, it will blow heat.

The line to the HVAC controls also contains a vac canister and check valve. Without these, when you go WOT and lose vacuum, the HVAC will default to defrost/floor and remain there until vac is restored

Click to expand...
 
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