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The other day I was under the hood of my 2003 LX Coupe and noticed the cooling fans were not on when the AC was turned on (incidentally, dash temperature gauge was a little below half). Here is what I found:

- Condenser fan relay has power (with vehicle off, jumped 87/30 location and fan turned on)
- relay appears to work (powered it and checked continuity through 87/30 - 0.01 ohms)
- Radiator fan relay has power (same method as condenser)
- relay appears to work (same as condenser relay)
- compressor clutch appears to engage but haven't checked AC system pressures (yet)

Then jumped the radiator fan switch harness and both fans turned on. After reading lots of other threads and posts, this leads me to believe it is a faulty fan switch. I have priced it out and while not expensive, it is not cheap. So I wanted to check with the greater community to see if there is anything else I should check before buying the fan switch (for example, should I confirm AC system pressure before buying the switch?). Thanks!

Edited: realized I had the relay connections named wrong, oops

 
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If the compressor clutch is engaged then the fans should be on, regardless of the radiator fan switch. Ensure the compressor clutch is actually engaged. Air from vents should be cold.

 
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Took a closer look at compressor clutch, as you mentioned, it wasn't engaging with car running and AC on. Checked the relay and it is functioning (with good continuity check). I jumped the 87/30 location and the clutch engaged right away.

So, I am not getting a signal to operate the AC clutch relay?

 
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Check if you have enough pressure

 
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Threw on a set of manifold gauges after posting my last 'update'. There was low static pressure, I'd imagine this would be an interlock and prevent the compressor clutch engaging. Took a quick look online last night and finding r134a in my area seems like it could be a challenge

 
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? any car parts store carries them?

 
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I'm about to go check on several but none are showing any inventory online - only r12

 
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A refrigeration tech at work told me not to mix or substitute refrigerants. The auto parts store had r12 and the guy told me "it's the same as r134a, just use it". Do I trust the refrigeration tech or the parts dude??

 
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The can will say what its compatible with. Vehicles haven't used r12 since 96. Try a different parts store. R134a should be available everywhere

 
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Thanks @Colin42 Got one that said r12 / r134a compatible from a different store. Gave to system a little shot of it, the pressure came up to near equivalent as ambient temp in deg F. Thanks @BrotatoChip it definitely was not the fan switch, once the system had some pressure, the clutch engaged and both fans turned on. BUT the system has some problems, high side didn't pressure up past ambient

 
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Might need to add more, at least you have the proper manifold guages. With the clutch engaged it should build pressure in the high side

 
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Some good news, let the system sit for a couple of hours and the pressure was stable (I was wondering if there was a leak). But added some more refrigerant, low and high side pressures increased slightly but still high side wouldn't pressure up

 
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Issued has been resolved. Thanks! @Colin42 was correct, system needed more refrigerant. Once topped up system high / low pressures were pretty much bang on