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Old May 24, 2018 | 11:04 AM
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94 L8000

I have a 94 L8000 flatbed straight truck that has an air leak in the dash. The mechanics said it' the a.c. control switch and only leaks when the fan is on high. Doesn't sound right! They can't find a new switch, any ideas where to get one. Thanks
 
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Old May 24, 2018 | 12:28 PM
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Originally Posted by powers2018
I have a 94 L8000 flatbed straight truck that has an air leak in the dash. The mechanics said it' the a.c. control switch and only leaks when the fan is on high. Doesn't sound right!

They can't find a new switch, any ideas where to get one. Thanks
Which A/C switch are you referring to?
 
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Old May 24, 2018 | 04:48 PM
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That's all they said. I'm assuming the one controlling the fan.
 
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Old May 24, 2018 | 10:36 PM
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Originally Posted by powers2018
That's all they said. I'm assuming the one controlling the fan.
F1HZ-19986-A .. A/C Blower Switch (Motorcraft YH-518) / Obsolete

1991 and later L series trucks.

DON'S TRUCK SALES in Fairbank IA has 8 = 319-635-2751.

LONG LEWIS STERLING in Bessemer AL has 15 = 800-476-3716.

Call Jeff @ Auto Nation Ford Parts Dept in Phoenix AZ and ask if there's one closer. This is FTE member JEFFFAFA who posts in the 1967/72 forum
 
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Old May 24, 2018 | 11:30 PM
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thank you for your help I will check into those
 
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Old May 25, 2018 | 05:34 PM
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Don't think there's any air going to the AC controls, the fan switch is electric and I'm pretty sure the controls are cable operated.
 
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Old May 25, 2018 | 07:25 PM
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The entire system is vacuum not electric
 
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Old May 25, 2018 | 07:44 PM
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Last edited by 85e150; May 26, 2018 at 05:55 PM. Reason: remove wrong answer
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Old May 25, 2018 | 10:16 PM
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Never heard of a vacuum fan switch on those trucks, the fan switch is electric
The heat and AC controls used to be cable but that may have changed, my 86 was cable controlled.
We have a 94 in our fire house, I'll look at it this weekend.
I had a CL9000 with vacuum controls, it used a air venturi to create vacuum for the controls, sounded like a air leak under the dash evert time the key was on
 
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Old May 25, 2018 | 11:05 PM
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Originally Posted by powers2018
The entire system is vacuum not electric
The A/C and heater are controlled by cables. I don't see any vacuum switch or motors in the pic (that I cannot post because it's on microfiche).
 
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Old May 26, 2018 | 08:10 AM
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I wish I knew more. It's not an ac leak, is an air line leak according to the mechanic. The truck loses all air within 15 min after the engine is off.
 
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Old May 26, 2018 | 09:21 AM
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No one claimed your AC was leaking.
Not sure on that year model but on the older models I've had to replace a leaking brake light switch under the dash near the brake pedal.
Pretty common thing for that switch to start leaking after a while.
I also recommend you find a mechanic that knows these older trucks, with him saying it only leaks air with the fan switch on high, simply turning the switch off would stop the air leak.
Since you said it loses air within 15 minutes I'd bet it does it no matter where the HVAC switches and controls are set
Can you hear the air leaking inside the cab or is it just loosing air from somewhere?
 
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Old May 26, 2018 | 10:17 AM
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From the cab under the dash
 
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Old May 26, 2018 | 04:32 PM
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Is it leaking enough you can here it or just losing air?
 
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Old May 26, 2018 | 08:04 PM
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Oh yeah, pretty large leak.
 
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