# 1998 Neon A/C Recharge

**URL:** https://forums.speedlife.net/t/1998-neon-a-c-recharge/191290
**Category:** PittSpeed Automotive
**Created:** [July 21, 2007, 8:52am UTC](https://forums.speedlife.net/t/1998-neon-a-c-recharge/191290 "2007-07-21T08:52:29Z")
**Posts on this page:** 1
**Showing post:** 5

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### Author: ![berad](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/berad/32/5953_2.png) [@berad](https://forums.speedlife.net/u/berad)
#### Post date: [July 23, 2007, 2:04pm UTC](https://forums.speedlife.net/t/1998-neon-a-c-recharge/191290/5 "2007-07-23T14:04:27Z")

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> [@KeithO"](#):
>
> Car A/C systems are a real pain.
> 
> The systems that I have worked on (and it sounds like yours works the same), have two “inputs” for the compressor to run. The first “input” is the selector switch on the dash - e.g. turn on the A/C. The second “input” is a differential pressure switch. The differential pressure switch checks the high side and low side pressure of the compressor and if the difference in pressure isn’t high enough, it “turns off” the “input” and the compressor won’t run. This is a self-protection mechanism to reduce damage when the system is low on refridgerant. The pressure cycling the you are seeing is likely the differential pressure switch deciding to shut off the compressor.
> 
> At this point, I don’t recommend running the system until you find your leak. Once you find the leak, you can decide what the next course of action should be.
> 
> These systems are rarely easy or cheap to fix. Trust me - I’ve have a few systems go bad for various reasons.
> 
> Let me know what you find, I might be able to give some advice…

Don’t see a leak. Am I ok to disconnect the sensor at the compressor? It must be reading proper psi on low side where I filled it vs. nothing on the high side (assuming) since there was no pressure in the system and the safety turns off the compressor before the freon has a chance to circulate thru.

> [@Catch Air](https://forums.speedlife.net/t/catch-air/31434/19):
>
> My neon has always done this…it was out of coolant for a while and wouldn’t get cold…got a refill thing from kmart…filled it without a gauge(dumb) and it is cold as hell now, my ac pump has always seemed to “breathe” on-off-on-off

That doesn’t mean its working properly. I knew immediately that the cycling sound wasn’t right.

> [@drury a king?](https://forums.speedlife.net/t/drury-a-king/31473/14):
>
> If the pressure in the system gets too high/low it will cut out the compressor.

I think the pressure is indifferent rather than too high right now.

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