RV9Factory
Well-known member
Hi Folks,
I've been screwing around with this all day and have finally decided I need help/input.
For a couple of weeks the a/c in my '06 Jetta BRM has been going flaky. It started with the interior blower motor going weak. so I removed, disassembled, cleaned, lubricated and put it back in. It was a lot better but not for long so I ended up replacing with a new one from Autozone. It was 500% better. I replaced the cabin air filter while I was at it.
Within days I started getting the all-too-common RCV failure symptom. This happened to me a couple years ago (same car) so I was familiar with it: A/C took >10 minutes to cool and was intermittent.
While checking under the hood I noticed that the smaller of my cooling fans wasn't turning. So I pulled it, took it apart and found that the brushes were gacked with spooge. I cleaned it all up, put it back together and both fans seem to run great. But I still had the problem.
I had the freon pulled and removed the RCV. It looked good (no particles) so I hit it with 12V and it actuated. I did that repeatedly and nothing seemed to be wrong. I don't have a replacement so I put new o-rings on it and re-installed. I pulled a vacuum for a couple hours, gave it 15 min to make sure vacuum held and then started charging w/ vapor & engine off. Once nothing more would go in, I started the car with A/C on full blast and here's where it got interesting.
When I started the car, the low side pressure immediately dropped to somewhere between 25 and 40 psi, for a minute or so, then shot up to 90, which sent me diving for cover because I don't trust those cans. I shut the car off, gave it a minute and then restarted it. Pressure again dropped, held for a 15 seconds or so, then went back up to between 85 and 95. Rinse and repeat. I eventually got a can of freon in.
During one of those cycles before starting the car I hooked a multimeter to the connector at the RCV (disconnected). I never saw any voltage at all at that connector. If I had a mating plug I'd put 12V into the RCV and see if I could get cold air doing that.
I suspect (but could surely be wrong) that for some reason the computer is never commanding the RCV valve to do whatever it does. I think tomorrow I might find the other end of the positive wire going to the RCV and hook it into 12V to see if that makes it work.
In the meantime, does anyone have any thoughts or troubleshooting tips for this? Unfortunately I don't have VCDS available. The only thought that comes to mind is the evaporator temperature sensor - could the car think it's colder than it is and be reducing the compressor output? If so, is it normal to see 85-95psi on the low side when the car isn't asking for compressor output?
Two other items just on the off chance they make a difference:
When I pulled the RCV I noticed that the compressor oil looked really clean, had a very light yellow/amber tint and was transparent with no particles - but had a smell reminiscent of burnt circuit board if anyone is familiar with that. Not a charred or smoky smell - more "chemical" smelling.
Second, for a while now [couple of months] I've been having some turbo issues and the car goes into limp mode. I think I have that vane actuator issue but haven't had time to confirm.
Thanks!!
I've been screwing around with this all day and have finally decided I need help/input.
For a couple of weeks the a/c in my '06 Jetta BRM has been going flaky. It started with the interior blower motor going weak. so I removed, disassembled, cleaned, lubricated and put it back in. It was a lot better but not for long so I ended up replacing with a new one from Autozone. It was 500% better. I replaced the cabin air filter while I was at it.
Within days I started getting the all-too-common RCV failure symptom. This happened to me a couple years ago (same car) so I was familiar with it: A/C took >10 minutes to cool and was intermittent.
While checking under the hood I noticed that the smaller of my cooling fans wasn't turning. So I pulled it, took it apart and found that the brushes were gacked with spooge. I cleaned it all up, put it back together and both fans seem to run great. But I still had the problem.
I had the freon pulled and removed the RCV. It looked good (no particles) so I hit it with 12V and it actuated. I did that repeatedly and nothing seemed to be wrong. I don't have a replacement so I put new o-rings on it and re-installed. I pulled a vacuum for a couple hours, gave it 15 min to make sure vacuum held and then started charging w/ vapor & engine off. Once nothing more would go in, I started the car with A/C on full blast and here's where it got interesting.
When I started the car, the low side pressure immediately dropped to somewhere between 25 and 40 psi, for a minute or so, then shot up to 90, which sent me diving for cover because I don't trust those cans. I shut the car off, gave it a minute and then restarted it. Pressure again dropped, held for a 15 seconds or so, then went back up to between 85 and 95. Rinse and repeat. I eventually got a can of freon in.
During one of those cycles before starting the car I hooked a multimeter to the connector at the RCV (disconnected). I never saw any voltage at all at that connector. If I had a mating plug I'd put 12V into the RCV and see if I could get cold air doing that.
I suspect (but could surely be wrong) that for some reason the computer is never commanding the RCV valve to do whatever it does. I think tomorrow I might find the other end of the positive wire going to the RCV and hook it into 12V to see if that makes it work.
In the meantime, does anyone have any thoughts or troubleshooting tips for this? Unfortunately I don't have VCDS available. The only thought that comes to mind is the evaporator temperature sensor - could the car think it's colder than it is and be reducing the compressor output? If so, is it normal to see 85-95psi on the low side when the car isn't asking for compressor output?
Two other items just on the off chance they make a difference:
When I pulled the RCV I noticed that the compressor oil looked really clean, had a very light yellow/amber tint and was transparent with no particles - but had a smell reminiscent of burnt circuit board if anyone is familiar with that. Not a charred or smoky smell - more "chemical" smelling.
Second, for a while now [couple of months] I've been having some turbo issues and the car goes into limp mode. I think I have that vane actuator issue but haven't had time to confirm.
Thanks!!