I am a HVAC tech. for residential and commericial applications. I do not due much with automotive. I have a 1991 Vr4 and the air conditioning has been fine. No leaks in its history. The other evening a met a few other guys in my area who both have vr4's. My Vr4 is stock and they asked me if I wanted to put the k&n intake with the chopped box on b/c they had a spare one. I let them do the work which took a few minutes. I made a few hard runs on the car to see monitor the new intake performance. At that point I noticed that with the AC selected in the car no cold air was blowing out. Keep in mind I was just using the AC this same evening and it was fine. I dont know if while installing the intake something happened or if it is just coincidental. Either way, it dooesnt seem like my compressor is turning on. I only hear the condensor fan turn on but no "click" from the compressor. Any help would be appreciated. Worse case scenario the compressor is bad. I did observe that the clutch on the compressor was operating during the AC call. I also think that maybe a fuse is blown. I noticed there are some round style fuses on the passanger's side engine bay. Are they related to the AC? Thanks.
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ken inn
Well-known member
on top the thermostat housing is a sensor for the a/c. it is kinda in the way, and might have gotten either removed(i remove it all the time when i am doing stuff in that area) or bumped and broke.
Terry Posten
Well-known member
quote:Originally posted by ken inn:
on top the thermostat housing is a sensor for the a/c. it is kinda in the way, and might have gotten either removed(i remove it all the time when i am doing stuff in that area) or bumped and broke. Ken, your a GOD! Thank you, thank you, thank you.
My A/C just stopped about 2 weeks ago. Worked on a 30 mile trip to my mothers and didn't on the return trip. I thought the comp was dead. The pressure gauge read 110psi. I thought that meant the comp was pressurizing both hi and low.
Your reply to this post turned on a light, a million candle power light. I checked and sure enough, 1 wire was broke and the other was hanging by a thread. Not easy fixing it, at 11:00 at night, but I pulled the terminals out of the plug and soldered new wires on them and sure enough, it WORKS....
5 big stars for you. If you do sell your car, PLEASE keep up with us. Your knowledge is worth more to us than you know.
Thank you.
(I know, maybe a little over board, but I was actually thinking about selling 425 for something newer, with a working AC. Now I don't have those bad thoughts anymore.
)
on top the thermostat housing is a sensor for the a/c. it is kinda in the way, and might have gotten either removed(i remove it all the time when i am doing stuff in that area) or bumped and broke. Ken, your a GOD! Thank you, thank you, thank you.
My A/C just stopped about 2 weeks ago. Worked on a 30 mile trip to my mothers and didn't on the return trip. I thought the comp was dead. The pressure gauge read 110psi. I thought that meant the comp was pressurizing both hi and low.
Your reply to this post turned on a light, a million candle power light. I checked and sure enough, 1 wire was broke and the other was hanging by a thread. Not easy fixing it, at 11:00 at night, but I pulled the terminals out of the plug and soldered new wires on them and sure enough, it WORKS....
5 big stars for you. If you do sell your car, PLEASE keep up with us. Your knowledge is worth more to us than you know.
Thank you.
(I know, maybe a little over board, but I was actually thinking about selling 425 for something newer, with a working AC. Now I don't have those bad thoughts anymore.
Ok, I just checked the wires on the sensor and fixed them, but the air compressor still won't turn on, fuses are good. The AC stop working after a jdm engine replcaement. any suggestion?
ken inn
Well-known member
if you used the cyclone intake, and the surge tank bracket is still on there, the bracket will cut the hot line to the clutch.
I use the USDM intake Mani. I think it is a electrical problem. I just can't find out where
Do you have a logger? I have posted a couple other times recently that the logger will show you 2 things for the A/C:
1) the status of the power switch, and
2) the status of the clutch
If you NEVER see either of them come on, then usually it is either the high/low pressure switch or the temperature switch on top of the thermostat housing. When you turn on the power, the A/C computer sends out +12 volts to the high/low pressure switch. If everythings OK there, the +12 volts continues on to the temperature switch. If everything is OK there, it should end up at pin 65 of the ECU, IIRC, which makes the "A/C switch" come on on the logger. Then, if the ECU thinks everything is OK, it turns on the compressor clutch.
Jeff
1) the status of the power switch, and
2) the status of the clutch
If you NEVER see either of them come on, then usually it is either the high/low pressure switch or the temperature switch on top of the thermostat housing. When you turn on the power, the A/C computer sends out +12 volts to the high/low pressure switch. If everythings OK there, the +12 volts continues on to the temperature switch. If everything is OK there, it should end up at pin 65 of the ECU, IIRC, which makes the "A/C switch" come on on the logger. Then, if the ECU thinks everything is OK, it turns on the compressor clutch.
Jeff
Hey Guys. I took the vr4 to the car wash this evening and was cleaning the engine bay. I noticed that there was a terminal plug diconnected which sits on top of the radiator hose area of the passanger side engine bay. I looked at the plug and noticed right away that it got unplugged. I immediately plugged it in and then turned on the car and the AC worked! I was very happy because problems bother me until they are fixed. Now I got back home and figured I would check the forum to put an updated response that the AC was working again and how I was able to do it. Then I saw the reply suggesting to do the same thing I had done. Well, if I didnt figure it out that reply would have been a great help and would have saved me a trip to the dealer. Thanks.
so where is the high/low pressure switch? my MMCD version is 1.6j. Does it have the AC status? If so, what does it appear on the screen?
Screwed into the dryer/accumulator, below the coolant overflow bottle.
Hertz
Staff member
I'm going to feature this topic until there are no more posts for a few days and then move it to how-to. Thanks guys.
I use a voltmeter to check the voltage of connect to the Hi/lo pressure switch. I got 0.03 voltage with AC turn off and 0.07 voltage with the AC tun on. the compressor never kick in
. In addition, he cel light came on and I got a code 21. Where should I check?
