My 09 rabbit. Has this issue where you'll turn the a/c on the switch lights up but the a/c doesn't get cold the cooling fans do not come on. Then out of no where it'll randomly work and when it does it's flawless cooling fans come on when sitting and the air out of the vents is cold. Pressures were around 40/125 at idle when it was roughly 60-65 outside. There is no codes in the car for the HVAC or anything else actually.....could this be the solenoid on the compressor I've read about? What do y'all recommend?
VW mk5 a/c intermittently works
- Thread starter ram_man
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Is there a relay? If so I would start there many newer cars have all sorts of weird sensors like evap temp and who knows what else. If any of those are acting up it will need to be properly diagnosed.
The coolant temp switch sometimes goes flaky with some models with 2 in the pipe at the rear of the engine. The Sanden compressor valve issue is usually not intermittent.
Check for clutch operation, if its working the issue is not electrical if not check for relay voltage, voltage in and out of the coolant temp sensor at operating temp and voltage in and out of the pressure switch.
If no volts out at the relay but voltage going in you may also be dealing with a bad switch, jumping it can help trouble shoot but be careful jumping terminals.
Check for clutch operation, if its working the issue is not electrical if not check for relay voltage, voltage in and out of the coolant temp sensor at operating temp and voltage in and out of the pressure switch.
If no volts out at the relay but voltage going in you may also be dealing with a bad switch, jumping it can help trouble shoot but be careful jumping terminals.
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I have replaced the refrigerant control valve on four of these 5th generation Volkswagen cars for delayed operation. It's a relatively inexpensive part and does require the recovery of the refrigerant to perform. The main thing is to not spend the small fortune for a new compressor without thorough diagnosis.
Nick1994
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My aunt's 13' VW Beetle TDI did the exact same thing. Sometimes 10-15 minutes in 110+ degreee heat with no A/C in a $30k car.
Took 3-4 trips to the dealer and they replaced temp sensors, drained and refilled the refrigerant, the main control for the A/C, then finally the compressor and that fixed it...........for about 6 months. Then it did the same thing.
Took 3-4 trips to the dealer and they replaced temp sensors, drained and refilled the refrigerant, the main control for the A/C, then finally the compressor and that fixed it...........for about 6 months. Then it did the same thing.
If the interior fan is not coming on , find a book with the wiring diagrams / schematics for the car . Follow the circuit from the power source / battery to the fan . Check each device , connection , splice .
The person that mentioned the coolant temp sensor may or may not be right . Same for the HVAC controler .
I know nothing specific about a VW . I can say the 2007 Silverado company truck I drive had the interior fan die , last summer . Got on youtube & found a video on the fan controler . Replaced that part and all is / was well . Gad nothing to do with the refrigeration system .
So , check for a video on you tube .
Here is a link to the blower controler / resister at rockauto.com ;
https://www.rockauto.com/en/catalog/volkswagen,2009,rabbit,2.5l+l5,1443782,heat+&+air+conditioning,blower+motor+control+module+/+resistor,6557
The person that mentioned the coolant temp sensor may or may not be right . Same for the HVAC controler .
I know nothing specific about a VW . I can say the 2007 Silverado company truck I drive had the interior fan die , last summer . Got on youtube & found a video on the fan controler . Replaced that part and all is / was well . Gad nothing to do with the refrigeration system .
So , check for a video on you tube .
Here is a link to the blower controler / resister at rockauto.com ;
https://www.rockauto.com/en/catalog/volkswagen,2009,rabbit,2.5l+l5,1443782,heat+&+air+conditioning,blower+motor+control+module+/+resistor,6557
Given how cheap relays($7-$20) are I'd suggest replacing AC one and see what transpires.
This has fixed AC in my upper mileage(175k+) Acura, Honda and Subaru. Please note that two of vehicles went through complete diagnosis finding nothing and then I replaced as last resort. I am not a parts thrower but intermittent relays can be difficult to diagnose.
This has fixed AC in my upper mileage(175k+) Acura, Honda and Subaru. Please note that two of vehicles went through complete diagnosis finding nothing and then I replaced as last resort. I am not a parts thrower but intermittent relays can be difficult to diagnose.
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Ugh. My wife's 2008 Rabbit has similar issues. I've replaced the valve in the compressor and that seemed to help, kinda... but she tells me it is not working well again. I'm hesitant to throw parts at it, as far as I can tell there is nothing wrong with the AC system itself... when it works it works well.
After looking into it a bit you may need one of these, it seems to be a common problem on this model. Make sure the charge is full also. Do you have a VW scan tool?
https://www.partsplaceinc.com/vw-am...oqqed4QIVg4CfCh05AQzcEAQYAiABEgLhuPD_BwE
https://www.partsplaceinc.com/vw-am...oqqed4QIVg4CfCh05AQzcEAQYAiABEgLhuPD_BwE
Does it have one or two coolant sensors? Did you check the charge and for power going to the clutch?
all modern cars are VERY complicated with LOTS of sensors + many with the "fancy" touch screens are worse BUT a VAGcom scan with a knowledgeable operator can sort it out. this is a great forum but VWVortex.com is best for VW's + if lucky a close member with a VAGcom could possibly help you or of course a pro air condition specialist, good luck
Originally Posted by ram_man
My 09 rabbit. Has this issue where you'll turn the a/c on the switch lights up but the a/c doesn't get cold the cooling fans do not come on. Then out of no where it'll randomly work and when it does it's flawless cooling fans come on when sitting and the air out of the vents is cold. Pressures were around 40/125 at idle when it was roughly 60-65 outside. There is no codes in the car for the HVAC or anything else actually.....could this be the solenoid on the compressor I've read about? What do y'all recommend?
Relay! Relay! Relay!
Had same issue on 2005 B5.5 1.8T. Do not be me! I saw Denso AC compressor on sale for $180, bought it, installed it, same thing.
It did not occur to me to barrow from my roommate relay. She drove 2001 Passat. When I put relay from her car everything was OK. Relay on Ebay was like $9!
My 09 rabbit. Has this issue where you'll turn the a/c on the switch lights up but the a/c doesn't get cold the cooling fans do not come on. Then out of no where it'll randomly work and when it does it's flawless cooling fans come on when sitting and the air out of the vents is cold. Pressures were around 40/125 at idle when it was roughly 60-65 outside. There is no codes in the car for the HVAC or anything else actually.....could this be the solenoid on the compressor I've read about? What do y'all recommend?
Relay! Relay! Relay!
Had same issue on 2005 B5.5 1.8T. Do not be me! I saw Denso AC compressor on sale for $180, bought it, installed it, same thing.
It did not occur to me to barrow from my roommate relay. She drove 2001 Passat. When I put relay from her car everything was OK. Relay on Ebay was like $9!
Originally Posted by ram_man
Which relay was it?
I think, I think No.13
This was like 10 years ago, so...
Which relay was it?
I think, I think No.13
This was like 10 years ago, so...
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Here is what I found pressures 45 and 75 rev the car up a little high side rises to around 45/150 and the fans kick on and it works . Even when it wasn't working the compressor did have power. So at this point I'm leaning toward the. Solenoid on the compressor.
Originally Posted by ram_man
Here is what I found pressures 45 and 75 rev the car up a little high side rises to around 45/150 and the fans kick on and it works . Even when it wasn't working the compressor did have power. So at this point I'm leaning toward the. Solenoid on the compressor.
I would again check relay. Do you know anyone with VW to swap?
Here is what I found pressures 45 and 75 rev the car up a little high side rises to around 45/150 and the fans kick on and it works . Even when it wasn't working the compressor did have power. So at this point I'm leaning toward the. Solenoid on the compressor.
I would again check relay. Do you know anyone with VW to swap?
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