940 1994 a/c

joooro · Post by **joooro** » 27 Apr 2009, 21:39

Could anyone help me locate a relay or fuse for the A/C clutch. It will not engage, and I want to check it before doing anything else...I have checked the freon and it is fully charged

Post by **billofdurham** » 28 Apr 2009, 15:42

Welcome to Matthew's Volvo Site.

There is neither a relay nor a fuse for the compressor clutch. To test that the compressor is working touch a jump lead to the + terminal on the compressor from the battery +.

Bill.

joooro · Post by **joooro** » 26 May 2009, 05:25

Is there a relay for A/C unit ,for 1994 940....? If so where is the location...It seems I do not have power to A/C unit.. and the fuse is good.. Thanks

Post by **billofdurham** » 26 May 2009, 12:24

There is no relay for the air conditioning.

Where, and how, are you testing for power?

Bill.

Post by **vegasjetskier** » 26 May 2009, 12:28

joooro wrote:Is there a relay for A/C unit ,for 1994 940....? If so where is the location...It seems I do not have power to A/C unit.. and the fuse is good.. Thanks

If you have Manual Climate control, no. If you have Electronic Climate Control, yes. The relay is in the red ellipse in the following diagram. It is located up under the dash (blue ellipse).

: 940ACRelay1994.jpg (119.25 KiB) Viewed 5079 times

joooro · Post by **joooro** » 26 May 2009, 18:06

billofdurham wrote:There is no relay for the air conditioning.

Where, and how, are you testing for power?

Bill.

I checked the fuse and checked power to the low limit switch...I pulled the plug of and check to see if there was voltage to the lowlimit switch...i did not get a reading there... I should have , right...?

Post by **billofdurham** » 27 May 2009, 12:00

There should be power there unless one of the sensors is detecting too much or too little pressure.

You said in your first post

I have checked the freon and it is fully charged

How did you check this? What pressure was there?

Bill.

bentrider · Post by **bentrider** » 21 Jun 2009, 12:37

Bill,
I have a question on this same topic or anyone that can answer me. What is the correct pressure for the refridgerant? My 940 shows about 60 lbs at idle with the a/c on full blast. I also noticed that when I unplug my gauge to the fitting there is some oil present. Is this normal? Could it be possible that the former owner added too much oil? It has only become a problem since the temp outside in the high 90s F I don't want to add anymore r 134-a if the pressure is already high or too high. What do you think?
Joe

Post by **billofdurham** » 21 Jun 2009, 16:00

Normal readings on high and low side with AC OFF (static pressure) - Depends on outside temperature, but normally is between 80-105 PSI
Normal low side reading with AC on high speed and MAX & engine at 800-1000 RPM’s - Ranges from 20-37 PSI -
Normal high side reading ranges from 114-170 PSI.

The operating pressures are at an ambient temperature of 86F (30C).

I think you have too much refrigerant in there. Overcharging just a little can decrease the performance of the system and possibly damage the compressor.

You will always get a trace of oil when you remove the gauge.

Bill.

bentrider · Post by **bentrider** » 21 Jun 2009, 20:10

Bill,
I removed some refridgerant down to about 37 psi. I took it out for a test drive with a temperature probe in the dash vent. The temp outside was approx 87 deg F at 9pm . At about 1000 rpm temp on my probe shows about 56 F. when I reach about 2000 rpm it stays around 43 F. Should I be seeing a 13 degree temperature difference? possible bad compressor?

I compared it with my 1992 Toyota camry and the temp only flutuated about 4 degrees F. and did not seem to make a difference if I was at 1000 rpm or 2500 rpm.

Both cars were at normal operating temperature between 9:00 - 10:00 pm at night @ aprox 87 F outside temp.

Any ideas?
Thanks Joe