1999 a/c power

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Jul 3, 2013 | 10:17 AM

shartflhs

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From: Connecticut

1999 a/c power

I have an early 99 F250. The a/c compressor stopped working. Have checked pressures, switches, freon etc. Found the switch in the dash is not getting power to send to the compressor. does anyone know where the feed for this switch is? I have checked all fuses, all good. The manual does not show a relay as being an a/c relay, so I am stumped without taking it somewhere now but I would like to avoid that.

Jul 3, 2013 | 10:50 AM

projectSHO89

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From: St Louis

Assuming a Super-Duty, the climate control mode switch is supplied by junction box fuse F24. See owner's manual.

The 99 Super-Duty does not use any relays to control the compressor clutch.

Jul 3, 2013 | 06:02 PM

shartflhs

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projectSHO89, Thanks for your reply. I checked the F24 fuse and it is sound so I guess I have an issue somewhere in the wiring between the fuse and the climate control switch. Do you know where I can get a schematic of the wiring besides from Helm at a reasonable price?

Thanks,

Steve

Jul 3, 2013 | 06:54 PM

projectSHO89

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From: St Louis

Got a meter? The circuit is very, very simple.

Jul 3, 2013 | 07:45 PM

shartflhs

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Yes I do have a meter. I will check the circuit tomorrow morning. You say it is very simple, by that comment do mean it is the only line on that circuit? Reason I asked that is that my blend door actuator and trailer charge relay still have power which is what the manual says is powered by that fuse. I still want a schematic though. Lots of other things I want to check out or be able to.

Jul 4, 2013 | 06:18 AM

projectSHO89

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From: St Louis

F24 > Mode Selector Switch > Cycling switch > High Pressure Cutout Switch > Clutch Coil. There is a splice off F24 that also feeds the blend door circuit.

Best bet for comprehensive schematics is to pick up a set of service CDs or DVDs off eBay. You can also check the repair guides at AutoZone's website and see what they offer.