AC not working

[cracker red]

1995 TI

Middle of Atlanta Summer = need air.

AC switch lights up - check
All fuses good - check

Low side has plenty of pressure (too much?) check

Compressor doesn't kick on/clutch engauge. I'm wondering if clutch might be bad, or it might be a switch on the evap canister that is sending a bad signal?

Anyway to jump the switch (4 wires) so I can confirm it's either the switch or the compressor/clutch?

[tiFreak]

if there's too much pressure it won't turn on, might have to take it somewhere and have them drain and refill it to spec

[cracker red]

I can drain/refill it myself, but I suspect something else....

Pretty sure the low side will have "high" pressure when the system is off.... the compressor isn't compressing the high side, so it's all equal.

[cracker red]

I'm wondering if there is a way to turn on the clutch myself with a 12v+ lead....and where to find the plug to do so.

[PrimeTimeSlime]

1995 TI

Middle of Atlanta Summer = need air.





I feel your pain!

[cracker red]

No idea WTF is wrong with this. Other day I messed with it again, and when I removed/replaced the relay it switched on and worked great.

Worked for 2-3 days, now is out again. It's an electrical problem (the kind I hate), and I've got no idea what is/what could be wrong. I'm going to try and find a new relay and see, but I doubt it.... They appear to be the same, and swapping them out will kick on the high speed fan.....doubtful it's the relay and all fuses are good.

uggh...

[J!m]

High and low side pressure have to be within spec- there is one pressure switch that monitors both (B9508). That switch may be bad. Pulling the relay allows it to pull in, but once the pressure is detected out of spec it trips off again. Pressure must be below 21 bar and above 2.6 bar on one switch (which is actually two inside) and above 16 bar on the other.

NOTE: multiply Bar by 14.5038 if your gages are PSI only...

This tells me the low side must be over 2.6 (37.7 PSI) but under 21 (304.6) and the high side must be over 16 (232.1)to satisfy them.

Since the pressure switches run off spring resistance, they can/will wear out. So, even if the pressure is 'right' it may still trip due to 'weak' springs in the pressure transducer. But since the range is so wide, you should be able to run it in the middle of range and have good results. If you are close to the 'tripping' pressure, you could have intermittent problems as you do.

There is also "Y2" which monitors the temperature of the A/C compressor. If temperature is high, it will trip off as well. I doubt it is that, but just thought I'd mention it...