89 Country Squire compressor clutch not getting power

[SVTDarin]

The clutch isnt engaging so I checked the plug and its not getting power. Fuse is good and the relay on drivers side fender was clicking so I replaced it but new one also clicks when ac is switched on. System is full of R12 and I dont know what to check next.

It does not have auto climate control.

Thanks

[sly]

If the relay clicks, the ECM is switching the AC off because it thinks the throttle is wide open. Check the TPS sensor. The relay should not click when installed unless the key is on and engine is not running. Then the ECM will disable the AC so as to not damage the compressor or it's clutch during engine start.

[SVTDarin]

If the relay clicks, the ECM is switching the AC off because it thinks the throttle is wide open. Check the TPS sensor.

snip

The car runs, drives, idles fine, how do I check the TPS sensor or what am I checking for?

[WagonMan]

Did you try jumping the low pressure switch? WagonMan

[gadget73]

Voltmeter from black to green on the TPS. With the key on and the throttle closed, it should be near 1 volt. The voltage should smoothly increase to about 4.5 volts with the throttle full open. If you have more than about 1.2 volts with the throttle closed, the TPS is most likely bad. You'll probably need some paperclips to poke into the connector in order to check this.

http://www.lincolnsonline.com/tech/00127.html

[SVTDarin]

TPS voltage is good. Rechecked compressor clutch and it is getting power. Any compressor clutch changing tips?

[gadget73]

Need the clutch removal tool, and the holding tool helps. Holding tool looks like this

https://www.amazon.com/Powerbuilt-648980-Conditioner-Clutch-Holding/dp/B004KEFCPU

most auto parts stores have the clutch removal tools. Use the holder, remove the nut in the middle of the clutch, then use the tool to pull it. There is a washer or stack of washers under the front hub, or maybe they'll be inside the hub. Those are the shims to set the air gap. Hang on to those. Under the hub is a snap ring, pull that and the pulley comes off. Under that is another snap ring, remove that and the coil comes off. Put it back together in the opposite order. Air gap between the pulley and the clutch face is I think .025 - .035 or somewhere in that region. Adjust the shim stack as needed to get there.


Ohm check the clutch coil before you get too far into this. If there is a high resistance connection somewhere, the clutch might not actually get enough power to operate but the volt meter will read voltage. Coil should be under 50 ohms. If its open, its f'd. If you read the coil OK, put a light bulb across the connection and see what it does. If it won't turn the light on, you've got high resistance somewhere in the circuit.

[SVTDarin]

Previous owner redid the AC a few years back and it has this style compressor on it now

[gadget73]

yeah thats the 89+ compressor. Still comes apart the same way as the old FS6, but the holding tool might be different. Never had to do one of those myself but AC clutches are all pretty similar.