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Discussion Starter #1
I was hoping someone can figure this out! I have a 02 Passat 2.8 that when I turn on the heat the ac turns on! I also test the climate control and I get error codes 478or 4F8, 4FA.513,53D AND 318. When I looked at the servo motors they seem to be working! Any ideas how to fix this?
 

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2x on what cuppie said.
Regarding the error codes, I found that clearing them was usually effective, particularly the flaps. The A/C pressure switch error might be real; if so, it will promptly return.
 

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Discussion Starter #4

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How's the flow thru the heater core? 'Tis winter-y outside - if the core is clogged, it'll seem like the A/C is on.....
 

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Discussion Starter #6
I had it flushed and I also notice that while I was rev the car that I got flow through the core but I also notice that the ac lines started to ice up. I put the climatronic on Econ and I still get the AC blowing. Its like its confused
 

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Discussion Starter #7
How's the flow thru the heater core? 'Tis winter-y outside - if the core is clogged, it'll seem like the A/C is on.....
The flow is not getting to the core. I bleed the system again but I couldn't find the other bleeder spots in the system I read about in the post on here. Im not sure what to look for anymore cause I keep getting more things to look at lol! I think it might be the climatronic cause I hear the flaps moving and everything but the Ac is over powering. It wont turn off in econ mode and I know this cause it actually gets colder when the system is turned on. in the summer I have the best A/C lol! but now I cant even really drive the car with the system on lol!
 

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All I can suggest is that you pull fuses until the damn AC shuts off. You are showing a lot more patience than I would have with this problem. Maybe that will reset your 318 code switch.
 

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All I can suggest is that you pull fuses until the damn AC shuts off. You are showing a lot more patience than I would have with this problem. Maybe that will reset your 318 code switch.
Yeah im looking that up now! I was told maybe 348 relay could be the issue. I have to see if there is something other then pulling the whole dash out for a simple problem!
 

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Cuppie is correct; there is no separate fuse for the A/C compressor clutch. Fuse 5 powers it, but some other things, too (heated seats, cluster).

In cars with manual A/C control, the 384 relay controls the A/C clutch (not 348). It has some timing functions and multiple inputs, so it's not a plain relay.

However, cars with Climatronic do not have a 384 relay--all the timing functions, etc., are integrated in the Climatronic head unit. The Climatronic energizes the 267 relay to turn on the A/C clutch--that's the relay you could pull to disable A/C. Top row, third from left, on 13-position aux relay panel.
Ref: Bentley schematic 58/6.
 

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Discussion Starter #13
Can anyone tell me how many servo motors an there location in my 02 Passat 2.8l ? I notice the previous owner has done some modifications lol!
 

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Yes! I can tell now thanks to you guys that work has been done on this car before me! The heat was ok but it really didn't kick in until I was like driving around on the highway.
This is a classic symptom of the system needing to be bled of air.
If you hear the servo flaps moving, don't jump to thinking that they are the problem.

I will give you some links to help troubleshoot the system.



Good luck.
 

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There is a green wire with (I think) a purple connector that goes to the compressor. I don't recall the exact spot for the V6. On the 1.8T, it's just to the passenger side of the compressor.
 

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Discussion Starter #17
Thank you so much for the links
This is a classic symptom of the system needing to be bled of air.
If you hear the servo flaps moving, don't jump to thinking that they are the problem.

I will give you some links to help troubleshoot the system.



Good luck.
Thank you so much for the links! I got the heat up an running now! It was air an crude still in the system! I will use some of the clr or something to give it another good cleaning! Thanks again!!!
 

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Checked what seemed like the a/c wire today on the 1.8T. The wire is green with a yellow line and the connector is green with purple ends. It's a single wire, connector is behind driver's side headlight. I was not able to look under the car to match it at that end, but I am pretty sure it's the right one.
 

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Make sure that you do not mix green and pink coolants. it creates sludge that gums everything up.
do a flush of your entire system. run some clr through it, put in some distilled water to fill the system, run the distilled water for a while. flush. repeat. then fill with proper g12 coolant.
 

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Also check your coolant reservoir. is there any chalky stuff in there? if so, likely green and pink coolant were mixed.
 
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