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Need help troubleshooting fresh air blower 01273
I thought I posted this last night but I can't find it so maybe I didn't hit "save"?
I'm trying to solve the blower problem. I have a "chonky Passat" 1999 Audi A6 Avant Quattro 2.8L with the hot weather package including solar sunroof and Climatronic. The components are arranged differently on the A6 than they are on the Passat/A4, plus I have the solar sunroof that is not documented in my Bentley manual. I found a schematic online but it's hard to read on my phone and I'm not sure if I know how to read it anyway.
The fan is blowing merrily away on sun power so the blower motor (V2) is ok.
I checked the solar sunroof fan relay #285 and the repairs to the solder joints are still good. I cleaned up the contacts for good measure.
The fuses are ok and I cleaned the contacts.
I replaced the blower control module (J126) with a junkyard one. No difference.
The Climatronic control panel is not dead; the display and vent doors respond to the buttons.
I haven't cut off the shrink wrap from the replacement connectors for the fan or resistor. The fan runs on solar so I presume that circuit is complete.
What else should I check? There's a blower motor resistor (N24) on the blower motor.
I'm trying to solve the blower problem. I have a "chonky Passat" 1999 Audi A6 Avant Quattro 2.8L with the hot weather package including solar sunroof and Climatronic. The components are arranged differently on the A6 than they are on the Passat/A4, plus I have the solar sunroof that is not documented in my Bentley manual. I found a schematic online but it's hard to read on my phone and I'm not sure if I know how to read it anyway.
The fan is blowing merrily away on sun power so the blower motor (V2) is ok.
I checked the solar sunroof fan relay #285 and the repairs to the solder joints are still good. I cleaned up the contacts for good measure.
The fuses are ok and I cleaned the contacts.
I replaced the blower control module (J126) with a junkyard one. No difference.
The Climatronic control panel is not dead; the display and vent doors respond to the buttons.
I haven't cut off the shrink wrap from the replacement connectors for the fan or resistor. The fan runs on solar so I presume that circuit is complete.
What else should I check? There's a blower motor resistor (N24) on the blower motor.
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I spent some time annotating the wiring diagram with component names and lines showing the wire colors (and thicknesses). What stumps me now is whether or not I need to find all the other diagrams that wires connect to, and how to do that. I have the Bentley but can't figure out how to translate the numbers in the boxes at the ends of the wires into "diagram where this goes next" using the book's numbering.
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The beginning of the electrical section in the Bentley has a few pages on how to read their diagrams.
The little box with a number in it at the end of a wire shows the next connection. Those corresponding numbers are along the bottom. For instance. in yours above, #15 connects to #17. Sometimes these numbers can be pages apart.
The little box with a number in it at the end of a wire shows the next connection. Those corresponding numbers are along the bottom. For instance. in yours above, #15 connects to #17. Sometimes these numbers can be pages apart.
That circuit board looks nasty. The bottom right pin looks to be missing most of its solder. I hate wiring diagrams, I had to buy a magnifying glass to read them when I had a Bentley manual.
I figured out most of the key, which helped a lot. I thought the line along the bottom was the ground connection?The beginning of the electrical section in the Bentley has a few pages on how to read their diagrams.
The little box with a number in it at the end of a wire shows the next connection. Those corresponding numbers are along the bottom. For instance. in yours above, #15 connects to #17. Sometimes these numbers can be pages apart.
Why does the forum eat most of my posts?That circuit board looks nasty. The bottom right pin looks to be missing most of its solder. I hate wiring diagrams, I had to buy a magnifying glass to read them when I had a Bentley manual.
My friend who touched up the solder (an EE who has been working on cars since he was 16 and now designs electric cars for a company other than Tesla) noted how nasty it was with grody old flux residue all over. The parts that look like the solder is properly flowed are his repairs. That was a couple of years ago.
The solder joints look fine to me but you could always just re-flow them if they are suspect. I'd suggest cleaning the board, though. Isopropyl alcohol should take the flux residue off without harm. A stiff brush (or an old toothbrush) can be used if needed.
@PZ , good catch! I pulled the relay and looked at it more closely. The lower right pin does look like it has a fine crack running around the solder joint.
I don't trust my soldering skills enough on a rare and spendy part like this, but I know someone at my maker space who's excellent and will help with small tasks.
@Iowegian , good idea about cleaning up the flux as long as it's out of the case anyway.
I don't trust my soldering skills enough on a rare and spendy part like this, but I know someone at my maker space who's excellent and will help with small tasks.
@Iowegian , good idea about cleaning up the flux as long as it's out of the case anyway.
Your problem indicates a problem with the relay circuit, and a few of those solder joints do look suspect.
That's an easier fix than the wiring or the climatronic!
Update: A different EE friend checked it for bad solder joints and said it's OK. I reinstalled the relay and somehow it worked again... for a few minutes. Then the fan stopped again.
Ideas?
Ideas?
Does it work after cooling down? Maybe some part of the circuit is failing when warm. I can't think of any reason why just removing/re-installing would fix things unless there is a dirty or bad connection somewhere.
Yeah, I suspect something might be wrong with the wiring to replace the connector on the blower control module (J129).* I don't have the tools to check it myself.Does it work after cooling down? Maybe some part of the circuit is failing when warm. I can't think of any reason why just removing/re-installing would fix things unless there is a dirty or bad connection somewhere.
It worked for a while when I'd been driving for over half an hour. The car was getting cold and I decided to try it again--and it worked like a champ. I thought it would work again on the way home, but no such luck. Not when the car was cold, not after it had warmed up, not after driving a while.
However, it seemed that when I had the heater and fan turned on (but not running), the climate control doors directed the fresh air past the heater core and it warmed up noticeably. When I turned off the Climatronic, it went cold again. (It was around 35-38F last night. Yes, I realize this is much warmer than many parts of the country, but for the southern end of Northern CA this is super cold. The lithium battery in my camera didn't like it much either. Why couldn't this comet make its approach later this year during the Perseid meteor shower when the nights are warm and the coastal fog blocks the city lights? And why does the annular eclipse have to be in October when it's too cold to camp in most of the good viewing places?)
*I had a problem a few years ago where the connector on J129 got hot enough to scorch the sound insulation on the backside of the glovebox assembly, melt, and burn the insulation on the wires. I don't know if the J129 had failed or what, but I didn't want to leave it on continuously and melt another connector. I checked the connector and the J129 and they were not particularly warm. The J309 relay #385 was warm, but it was near the warm air duct and IDK if it is warm during normal operation.
The fuses should protect the wiring from getting burnt if the current is going through them. If something is getting hot enough to burn then either the fuse size is wrong or the current isn't going through the wires but taking an unintended path or there is an unintended high resistance point in the circuit.*I had a problem a few years ago where the connector on J129 got hot enough to scorch the sound insulation on the backside of the glovebox assembly, melt, and burn the insulation on the wires. I don't know if the J129 had failed or what, but I didn't want to leave it on continuously and melt another connector. I checked the connector and the J129 and they were not particularly warm. The J309 relay #385 was warm, but it was near the warm air duct and IDK if it is warm during normal operation.
I don't know the functions of those relays but if they are related to the issue at hand, I'd check all the circuit connections, including grounds and the resistance across the relay terminals, especially the power connections that turn the relay on/off to see if anything looks off.
Thanks for the information. These aren't things I can do myself, but knowing what to tell someone to look for could be valuable. ("X, Y, Z need checking" is a more reasonable ask than "It isn't working and I don't have a clue why".) I can see what I can find in the way of schematics for the components.
Checking fuses is about my speed for electrical work so I've checked all related fuses. I haven't found any blown fuses or fuses of the wrong value.
Checking fuses is about my speed for electrical work so I've checked all related fuses. I haven't found any blown fuses or fuses of the wrong value.
The J309 relay module is to select the appropriate fan power source, either solar or car battery.
The relay contacts are a likely possibility, but it could be bad solder joints (sometimes they crack, and you can't see the cracks.)
It could also be a bad connection to the relay module.
You need to use a meter to check for correct voltage at all related points.
The relay contacts are a likely possibility, but it could be bad solder joints (sometimes they crack, and you can't see the cracks.)
It could also be a bad connection to the relay module.
You need to use a meter to check for correct voltage at all related points.
Thanks! I don't have the equipment or expertise to check the wiring or do more with the relay. One thing though, I'm not sure how to tell if it seated properly in the connector. I'd feel dumb if that was the problem but it would be great if it were an easy fix.
I have noticed the fan rotates weakly, but enough to feel cold air on the passenger side. I think the most probable issue is worn fan brushes. I ordered some new brushes on Amazon because it looks pretty easy on YouTube to swap motor brushes.
If the motor brushes were the problem, it wouldn't run properly on either solar power or car battery.
If it was mine I would re-solder most of the connections on the PCB, you could send it to a good module repairer.
If it was mine I would re-solder most of the connections on the PCB, you could send it to a good module repairer.
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