98 Cherokee 4.0. AC compressor clutch not getting 12V power. AC relay has been replaced and the 10A fuse is good. Blower switch is working, and it's charged.

Any particular place to look next?

 

Examine the Clutch fuse in the PDC. See pic.



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I checked and it's okay. Even cleaned the terminals. Thanks.

 

but are you getting POWER to the fuse?
If you do not have a test light... troubleshooting any electrical issue can be ... an issue...

 

Good suggestion, I'll check as soon a it stops raining! Thanks!

 

Check for power at fuse, then check both high and low pressure switches.

 

If you are confident your system is charged up to spec (see chart) you can check the Low Pressure Cycling Clutch Switch by removing the connector from the switch (on top of the accumulator) and jumping the two pin cavities in the body harness connector using a small paper clip, or equivalent, and see if the compressor engages with AC selected. If it does, check the switch by using an Ohmmeter. Probe both pins in the switch - you should see continuity on the Ohmmeter.


The switch is normally open. If the system pressure is below 20.5 psi the switch opens, and resets at above 34-38 psi. If your system is charged and the switch reads open the switch is defective.


If the compressor won't engage (as above) and it is determined the Low Pressure Switch is serviceable, jump the High Pressure Cut-Off Switch connector (as above) with the Low Pressure Switch reconnected. If the compressor engages the High Pressure Switch may be defective.


The High Pressure Switch is normally closed and will open if the discharge line pressure rises to above 450-490 psi.


AC Pressure/Temp Chart:



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Low Pressure Switch being jumped using a paper clip:



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Location of the High Pressure Switch:



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Your paper clip test found the low pressure switch bad.

Thanks for your post and test procedure!

 

I take it that it's fixed now....