My climate control is going hot and cold if I am going up or down hill

Tiny
OLGEORGE
  • 1986 FORD CROWN VICTORIA
  • 15,000 MILES

Where can I get a diagram of the vacuum lines and controls for the climate control system on an '86 Ford Crown Vic. Or Merc. Grand Marquis? We have one of each. The Merc. AC blows cold air on level or going downhill, but blows hot on an upgrade. The CV w We have both an '86 Crown Vic. And an '86 Grand Marquis. On the Merc. The AC blows cold air on the level or downhill, but blows hot when on an upgrade. The Crown Vic won't heat and the core is not plugged up. When the control lever is set on "floor" the vent door opens and the blower stops. I can't find any vacuum leaks. The doors in the plenum can be heard opening and closing as the lever is moved. I'm thinking the hoses may have been mis-routed at some time.

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Wednesday, October 12th, 2011 AT 10:45 PM

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Tiny
JACOBANDNICKOLAS
  • EXPERT
  • 68,399 POSTS

That really sounds like a vacuum leak. It sounds like the blend door is opening.

The first picture is a vacuum diagram of the HVAC system. The second is a wiring schematic. Let me know if they help. Just so you know, they are the same for both vehicles, ford / Merc.

Joe

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Wednesday, October 12th, 2011 AT 11:17 PM
Tiny
OLGEORGE
  • MEMBER

Both diagrams are of the wiring.

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Thursday, October 13th, 2011 AT 11:42 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
  • 68,399 POSTS

I am sorry about that. Here is the vacuum diagram. I must have selected wiring rather than vacuum when I sent it. Let me know if this helps.

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Friday, October 14th, 2011 AT 12:07 AM
Tiny
OLGEORGE
  • MEMBER

I SCREWED UP! The cars both have the automatic climate control system, which is more complex than the standard system. There is a sensor/switch in the heater hose under the hood and another sensor behind the dash above the glove box. There are also more vacuum lines under the dash. Is there any hope of my being able torepair these things, or will I need professional help? I've not been able to find anyone who will look at it.

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Friday, October 14th, 2011 AT 3:59 PM

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