94 Air Conditioning Question
Thread Starter
|
Amateur
Joined: Jun 2006
Posts: 31
Likes: 0
From:
94 Air Conditioning Question
Hey Everyone.
This is my first post here.
I was over at my dads house today and we were working on the AC trying to figure out why it isn't working. When I push the AC button on, the clutch on the AC Compressor never engages. We disconnected the plug that is about 8" off the compressor it self and grounded the ground and jumped from the positive on the battery to the other wire and the clutch engaged. We let it run like that for about 2 minutes but the air never got cold. So that’s one issue.
We also took the dash apart to make sure the switch was working. We finally found out that it did work, but for what ever reason it wont engage the clutch on the AC compressor. We looked up the wiring diagram and saw that the Low and High Pressure Switch have to check out ok before it will allow the AC Compressor to work.
So the questions are:
1 - If there is no Freon, or not enough will this kick the system into a protection mode and not allow the AC Compressor to work?
2 - Where are the Low Pressure and Hi Pressure switches? (see picture at the bottom of this post...)
3 - Is there anything I'm overlooking that you can recommend I check out?
Any suggestions are greatly appreciated and thanks for being here!
About the truck: I just got it on Thursday! Its a 94 Dakota Sport, Extra Cab, 5.2, Auto, 2wd, 159k miles, all original as far as I can tell, Blue ext, Grey Interior, uhhh, yeah. Pretty clean for its age. Pretty stoked to get it!
Later
- Daniel -
Picture of AC System:
This is my first post here.
I was over at my dads house today and we were working on the AC trying to figure out why it isn't working. When I push the AC button on, the clutch on the AC Compressor never engages. We disconnected the plug that is about 8" off the compressor it self and grounded the ground and jumped from the positive on the battery to the other wire and the clutch engaged. We let it run like that for about 2 minutes but the air never got cold. So that’s one issue.
We also took the dash apart to make sure the switch was working. We finally found out that it did work, but for what ever reason it wont engage the clutch on the AC compressor. We looked up the wiring diagram and saw that the Low and High Pressure Switch have to check out ok before it will allow the AC Compressor to work.
So the questions are:
1 - If there is no Freon, or not enough will this kick the system into a protection mode and not allow the AC Compressor to work?
2 - Where are the Low Pressure and Hi Pressure switches? (see picture at the bottom of this post...)
3 - Is there anything I'm overlooking that you can recommend I check out?
Any suggestions are greatly appreciated and thanks for being here!
About the truck: I just got it on Thursday! Its a 94 Dakota Sport, Extra Cab, 5.2, Auto, 2wd, 159k miles, all original as far as I can tell, Blue ext, Grey Interior, uhhh, yeah. Pretty clean for its age. Pretty stoked to get it!
Later
- Daniel -
Picture of AC System:
Joined: Jun 2006
Posts: 5
Likes: 0
RE: 94 Air Conditioning Question
yes, if there is no freon then the system will not engage. from my understanding it's not necessarily bad for a compressor to run without freon, but it's actually the lack of oil that will damage the compressor. no freon usually means no oil.
Champion
Joined: Dec 2003
Posts: 4,119
Likes: 5
From: Sycamore, Illinois (displaced to Arkansas)
RE: 94 Air Conditioning Question
"1 - If there is no Freon, or not enough will this kick the system into a protection mode and not allow the AC Compressor to work? " Pretty much, yes.
"2 - Where are the Low Pressure and Hi Pressure switches? (see picture at the bottom of this post...) " The low pressure switch is located on the top of the accumulator. The accumulator is located right by the firewall on the passenger side of the engine compartment. The high pressure switch is located on the A/C line near the compressor.
I don't know what year they made the change from R-12 (actual Freon) to R-134a, but, you can look at the vehicle sticker (label on the engine compartment side of the hood) and that will tell you. I will assume it is R-134a.
The system has a charge capacity of 32 ounces of R-134a. Try adding some R-134a and see if that solves the problem (however, having too much of a charge is not good for the system either, when getting a can of R-134a, get a recharge kit that allows you to see the pressure on the low-side of the system [on the refrigerant line on the passenger side that is running to the accumulator from the condenser]). Having too much oil in the system will reduce the cooling ability (while, not having enough will damage the system) With the truck being nearly 13 years old, it probably has the same problem as what my '96 has, a leak some where (although, since I've added some refrigerant, it seems to be holding a little better)
I see you included a part of a wiring diagram that looks like a Chrysler one. If you did not already purchase a service manual, I would highly recommend buying or finding one (made by Chrysler, the Haynes and Chiltons are no comparison).
Anyways, give her a charge (buy a leak detector kit if you feel like it, IIRC they arn't too expensive) and see what that does. Post back.
Hope ya like the truck! I know I love mine!
"2 - Where are the Low Pressure and Hi Pressure switches? (see picture at the bottom of this post...) " The low pressure switch is located on the top of the accumulator. The accumulator is located right by the firewall on the passenger side of the engine compartment. The high pressure switch is located on the A/C line near the compressor.
I don't know what year they made the change from R-12 (actual Freon) to R-134a, but, you can look at the vehicle sticker (label on the engine compartment side of the hood) and that will tell you. I will assume it is R-134a.
The system has a charge capacity of 32 ounces of R-134a. Try adding some R-134a and see if that solves the problem (however, having too much of a charge is not good for the system either, when getting a can of R-134a, get a recharge kit that allows you to see the pressure on the low-side of the system [on the refrigerant line on the passenger side that is running to the accumulator from the condenser]). Having too much oil in the system will reduce the cooling ability (while, not having enough will damage the system) With the truck being nearly 13 years old, it probably has the same problem as what my '96 has, a leak some where (although, since I've added some refrigerant, it seems to be holding a little better)
I see you included a part of a wiring diagram that looks like a Chrysler one. If you did not already purchase a service manual, I would highly recommend buying or finding one (made by Chrysler, the Haynes and Chiltons are no comparison).
Anyways, give her a charge (buy a leak detector kit if you feel like it, IIRC they arn't too expensive) and see what that does. Post back.
Hope ya like the truck! I know I love mine!
RE: 94 Air Conditioning Question
daniel981,
I agree with dodgerules86, and it looks like you are on the right track by starting with the wiring diagram to figure it out. The system is most likely low on refrigerant, but to check, pull the connectors from the low and high pressure cutouts and simply jumper them, one at a time. DO NOT RUN THE COMPRESSOR ANY MORE THAN YOU HAVE TO, TO ACCOMPLISH TROUBLESHOOTING!!!!!!! RUNNING THE COMPRESSOR WITHOUT REFRIGERANT WILL DAMAGE IT. You also need to make absolutely certain of with refrigerant you are dealing with, r-12 or r-134a. They are not mixable. Like putting vegetable oil in the crankcase and rear end fluid in an automatic tranny---bye bye a/c.
If, in fact if it is low, you really need to get it repaired, especially if its r-12. At $30-$40/lb.
The stuff is not cheap, and you can't get it just anywhere.
Once you have determined that the system is in fact out of gas, you are money ahead to have the cause checked out by a automotive a/c shop. They'll leak check it and can repair it. Don't be surprised if its the seal on the compressor shaft, but it may not be. It could be a corroded aluminum line, or a rubber hose connection. If you opt to make the repairs yourself, these guys are real good to work with, and they have all the stuff at fair prices for auto a/c----Arizona Mobile Air Take it as far as you can on your own, just know when you are getting in over your head.
Good Luck!!!
P/M me if you need or want more help
I agree with dodgerules86, and it looks like you are on the right track by starting with the wiring diagram to figure it out. The system is most likely low on refrigerant, but to check, pull the connectors from the low and high pressure cutouts and simply jumper them, one at a time. DO NOT RUN THE COMPRESSOR ANY MORE THAN YOU HAVE TO, TO ACCOMPLISH TROUBLESHOOTING!!!!!!! RUNNING THE COMPRESSOR WITHOUT REFRIGERANT WILL DAMAGE IT. You also need to make absolutely certain of with refrigerant you are dealing with, r-12 or r-134a. They are not mixable. Like putting vegetable oil in the crankcase and rear end fluid in an automatic tranny---bye bye a/c.
If, in fact if it is low, you really need to get it repaired, especially if its r-12. At $30-$40/lb.
The stuff is not cheap, and you can't get it just anywhere.
Once you have determined that the system is in fact out of gas, you are money ahead to have the cause checked out by a automotive a/c shop. They'll leak check it and can repair it. Don't be surprised if its the seal on the compressor shaft, but it may not be. It could be a corroded aluminum line, or a rubber hose connection. If you opt to make the repairs yourself, these guys are real good to work with, and they have all the stuff at fair prices for auto a/c----Arizona Mobile Air Take it as far as you can on your own, just know when you are getting in over your head.
Good Luck!!!
P/M me if you need or want more help
