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Thread: Help with AC Auxilliary Fan and K1 Relay

  1. #1
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    Help with AC Auxilliary Fan and K1 Relay

    My auxiliary fan will not turn on when I hit the AC button. I have tried jumping the black + green/black wires and the black/brown + green/black wires on the thermo switch. The high speed side turns on and the low speed side does not. I know what you are thinking...its the resistor. Well, 2 fans fail and one has a bypassed (removed) resistor and it still does not work. I can hear the K6 relay click when I jump the high speed side but cannot hear the K1 relay click when I jump the low side. I swapped relays since they are the same so the issue is not the relay itself. Oddly enough I do get various voltage readings from the K1 relay and various fuses:
    3 - No Voltage (I assume I only get a reading if the fan is spinning on the low speed side?)
    18 - No Voltage (I assume I only get a reading if the fan is spinning on the high speed side?)
    19 - 12V
    20 - 12V

    K1 Relay:
    30 - 12V on AC switched on
    87 - GND (I believe)
    85 - Hot - 12V
    86 - Nothing

    Ground G200 is fine.

    I have read this post (http://forums.bimmerforums.com/forum...22&postcount=6) but it gives different readings than what Im getting so Im kinda going of the wiring diagrams instead. Not to mention the relays are not the same. Mine are 4 prong and the post refers to 5 prong relays.

    This post (http://forums.bimmerforums.com/forum...38&postcount=4) mentions a relay behind the control panel mounted to the blower housing but I don't know if trying to jump the thermo switch bypasses this. I dont know if this refers to the switch that is pressed when running the AC but the AC itself works. There is also mention of a diode in the fuse box. I have a spare fuse box but do not know exactly where this diode is located. Would that diode cause the low speed to not run even if jumping the thermo switch wires?

    Any ideas on what to check next? Based on the wiring diagram it as though the problem is the black wire between the thermo-switch and the K1 relay. If someone with a bit of experience can clarify this point for me: By jumping the low speed wires on the thermo switch should I be seeing pin 86 light up with 12V? And if I don't see 12V would it be safe to assume thats where the issue lies? Pin 86/black wire? I wonder if that diode is in between both the thermo switch and the AC control switch. If it is then the only thing they both have in common is the diode.

    And ideas? Do I appear to be on the right track with the black wire/pin 86?

    EDIT: Now that I think about it, it appears that my pin readings don't make sense based on the wiring diagram and the post above by ricardodn. His explanation matches the diagram and mine does not. I assume I could check out K6 relay and see if the readings are correct based on ricardodn and the wiring diagram. If that turns out to be the case, oh man.....
    Last edited by Pennyw1se; 08-03-2010 at 03:04 AM.

  2. #2
    richardodn's Avatar
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    Go through my post and tell me the readings you get at each measurement point.
    "Howdy, Folks!"

    1986 Delphin 528e - Has led a hard life, 290k and still alive.
    1989 Zinnoberrot 325iX Sedan - My winter snowmobile. (Deceased)
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    1. Check fuse 3 as this is main power to the fan. If this is bad replace it and try again.
    Fuse 3 is fine. Checked continuity on current and replaced with new, just in case.

    2. Check for voltage on the black wire connected to the fan speed resistor. You should see 12V. If you don't move on to checking the relay.
    No voltage seems to be getting to the black wire.

    3. Check for voltage on the red wire connected to the fan speed resistor. You should see less than 12V. I don't know what the correct value is but I'd guess around 6-10V. If you don't, the resistor is bad.
    No voltage seems to be getting to the red wire. Just in case I checked the resistor I removed and the resistor is reading 7 ohms (I have the "other" resistor, not the one in the Bentley manual). This is off of the same fan that I bypassed the resistor. Still no go.

    4. If you see the indicated voltage on the red wire and the fan doesn't turn then the fan is bad.
    Fans are good. To further test I suppose I could swap the wires to make the high speed wire trigger the low speed setting. But Im fairly confident the issue is not with the fan(s).

    Assuming we aren't seeing power to the resistor, next we check out the relay:
    I think this is where I'm at. No voltage to the resistor.

    See this post for the relay socket view. [BTW, does anyone know how to reuse attachments?]

    5. Pull the K1 fan relay from the fusebox.
    Tested with K6 and other similar relays. No clicks.

    6. Check pin 30 in the socket. You should see 12V hot at all times. If you don't, there is a wiring fault.
    The pin that I see as hot all the time is pin 85, not 30 like you and the wiring diagram show.

    7. Check pin 86 in the socket. You should see 12V when the AC switch is depressed. If not then the switch is bad or there is a wiring fault.
    The pin that I see as 12V when pressing the AC switch and dead when not is pin 30, not 86 like you and the wiring diagram show.

    8. Check pin 85 in the socket. This should be continuous to ground at all times. If not, there is a wiring fault. First check ground point G200 and make sure there is a good connection. Otherwise it is in the wire harness somewhere. G200 is behind the LH side of dash, above the brake pedal. There are a number of ground wires here and it has been known to come loose.
    G200 seems to be connected fine. Its not loose and I get a clean ground signal. But I cannot find a ground in any of the pins.

    9. Replace the K1 relay. Turn on the AC switch and check for 12V at fuse 3. If you don't see it, the K1 relay is bad.
    Relays are fine.
    -------------

    I assume that test 7 above is the same as jumping the low speed wires on the thermo switch correct (not how I tested but more of an FMI)? In other words if I want to perform these tests without hitting the ac button I can just jump the wires. Also, the pin readings should be the same for K6 relay, correct? So I can perform your tests on K6 by jumping the wires and match them to your results. If the results match then the wiring is messed up for K1. Is that a safe assumption or is there something else I should be looking at?

    Am I correct in assuming that jumping pin 30 with the ignition off or 86 with the ignition on and the AC button pressed to pin 87 should cause the fan to run?
    Last edited by Pennyw1se; 08-03-2010 at 02:06 PM. Reason: Automerged Doublepost

  4. #4
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    Yes depressing the switch and jumping thermo switch low wires is almost the same. They are in parallel but they get power from different fuses.

    To make sure I have this correct, you're seeing
    85 - hot at all times
    30 - hot when switched

    As for measuring the pins, are you using the socket diagram given in the linked post? The relay itself should be labeled. Does it match the socket diagram.

    In any event something isn't making sense here. What we are going to do next is probe the K1 (low) and K6 (hi) relay sockets and figure out what they are all hooked up to.

    1. Pull the K1 and K6 relays, and fuses 3, 18, 19, and 20. Disconnect the radiator thermo switch.

    K1 Relay

    2. Find which pin is showing hot at all times. It should be pin 30 but report which one it actually is.

    3. Find which of the remaining pins shows continuity to the socket for fuse 3. You'll probably have to check both sides the the fuse socket to figure this out. It should be pin 87.

    4. Put fuse 19 back in and jumper pins 1 (green/black) & 2 (black) on the thermo switch socket.

    5. Put the ignition in run. Find out which of the remaining 2 pins on the relay socket are now hot. Pull fuse 19 again. That pin should go dead. Turn the ignition off. It should be pin 86.

    6. Check the remaining pin. It should go to ground.

    K6 relay - rinse and repeat

    7. Find which pin is showing hot at all times. It should be pin 30 but report which one it actually is.

    8. Find which of the remaining pins shows continuity to the socket for fuse 18. You'll probably have to check both sides the the fuse socket to figure this out. It should be pin 87.

    9. Put fuse 19 back in and jumper pins now 1 (green/black) & 3 (black/brown) on the thermo switch socket.

    10. Put the ignition in run. Find out which of the remaining 2 pins on the relay socket are now hot. Pull fuse 19 again. That pin should go dead. It should be pin 86.

    11. Check the remaining pin. It should go to ground.

    I'll try and take the same measurements on my 89 tonight.
    "Howdy, Folks!"

    1986 Delphin 528e - Has led a hard life, 290k and still alive.
    1989 Zinnoberrot 325iX Sedan - My winter snowmobile. (Deceased)
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    1999 Audi A4 Avant Quattro - Crap can, but I'm in too deep.
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    UPDATE: Here are my findings. Very interesting, if I do say so myself.....

    To make sure I have this correct, you're seeing
    85 - hot at all times
    30 - hot when switched
    I was wrong. Its the other way around. 30 hot all the time, 85 12V when switched on K1.

    As for measuring the pins, are you using the socket diagram given in the linked post? The relay itself should be labeled. Does it match the socket diagram.
    OK, check out this PDF: http://www.billswebspace.com/E30Ligh...mationXMon.pdf
    Completely unrelated to the fan but it shows a diagram of the socket on page 6. That is what I have and it matches the pins on my orange relays.

    In any event something isn't making sense here. What we are going to do next is probe the K1 (low) and K6 (hi) relay sockets and figure out what they are all hooked up to.

    1. Pull the K1 and K6 relays, and fuses 3, 18, 19, and 20. Disconnect the radiator thermo switch.

    K6 Relay
    All tests of K6 relay result in the same values you have.

    K1 Relay
    2. Find which pin is showing hot at all times. It should be pin 30 but report which one it actually is.
    True.

    3. Find which of the remaining pins shows continuity to the socket for fuse 3. You'll probably have to check both sides the the fuse socket to figure this out. It should be pin 87.
    True.

    4. Put fuse 19 back in and jumper pins 1 (green/black) & 2 (black) on the thermo switch socket.
    Done.

    5. Put the ignition in run. Find out which of the remaining 2 pins on the relay socket are now hot. Pull fuse 19 again. That pin should go dead. Turn the ignition off. It should be pin 86.
    False. I get 12V on Pin 85.

    6. Check the remaining pin. It should go to ground.
    False. I get no ground anywhere.

    Here is the interesting part:

    Fuse Box Top

    Labeled with where the pins are located for K1 and K6.

    Fuse Box Bottom

    The diode and black wire that runs to the thermo-switch are on K1 pin 85, not 86. I checked for continuity. Pin 86 is what I believe to be ground. On this test fuse box I get continuity between K1 Pin 86 and K6 Pin 85 and the main Ground lead. However, on my installed fuse box I get no ground on K1 Pin 86.

    Just for the fun of it I jumped K1 Pin 30 to K1 Pin 87 and the fan spun at low speed so my assessment that the fan was good was true. At this point I just need someone to confirm that switched power is on K1 Pin 85 and Ground is on K1 Pin 86. If Ground is in fact on K1 Pin 86 then I might simply route a .75mm ground wire to Pin 86 until I can find a more permanent solution.

    Thanks!
    Last edited by Pennyw1se; 08-04-2010 at 02:04 AM. Reason: Update

  6. #6
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    E30 fusebox.gif

    Here were my results using the pin numbers on the attached diagram.

    K1
    30 - hot at all times
    85 - hot when ignition on and either snowflake switch on or thermo switch jumped green/black to black
    86 - continuous to ground
    87 - continuous to fuse 3

    K6
    30 - hot at all times
    85 - continuous to ground
    86 - hot when ignition on and thermo switch jumped green/black to black/brown
    87 - continuous to fuse 18

    Note that the sense of 85 and 86 change between the 2 relays. If you aren't having success on the continuity tests, make sure you are doing it right. Multimeter in ohm setting, leads in correct plugs on meter (usually different then locations for voltage), and measure the resistance between the 2 points you want to test for continuity. The value is typically less than 1 ohm. Meters will usually read 1 exactly if the circuit is open.
    "Howdy, Folks!"

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    1989 Zinnoberrot 325iX Sedan - My winter snowmobile. (Deceased)
    1998 Avus Blau 328iC - My topless summer girl.
    1999 Audi A4 Avant Quattro - Crap can, but I'm in too deep.
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    Awesome! So Pins 85 and 86 are swapped between K1 and K6? I am definitely not getting ANY continuity to GND on K1 Pin 86. I cracked open the fuse box and touched the solder at the bottom (as shown on my fuse box bottom picture above and I got no ground.
    So if my tests above are correct that means my ground pin is dead. Im going to run a small ground wire to that pin and test with the relay in. Thank you!!

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    The problem I had with similar symptoms was a bad connection at the plug(s) by the driver side headlight. After three days of chasing wires it was the wife that said "are the connections good" to which I said "of course, well maybe"... NOT. The two prong plug as i recall was bad, the socket was expanded and failed to make contact or made contact but then lost it intermitantly. I put a piece of tinfoil in the socket and it has worked great since.

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    Just to be sure, are you doing the test correctly? How about on the K6 relay between pin 85 and ground? The ground trace from K1 goes from the socket pin 86. That pin is soldered to the circuit board where the trace goes to pin 3 of C114. (C114 is the long white connector plugged into the board in your picture. Pin 3 is where the 2 brown wires are.) The K6 relay pin 85 has a jumper wire to the harness side of C114-3 and then the harness continues on to ground. If K1-86 has no ground and K6-85 does, then that indicates a board or C114 connector problem. You might just need to reflow the solder joint at K1-86.
    "Howdy, Folks!"

    1986 Delphin 528e - Has led a hard life, 290k and still alive.
    1989 Zinnoberrot 325iX Sedan - My winter snowmobile. (Deceased)
    1998 Avus Blau 328iC - My topless summer girl.
    1999 Audi A4 Avant Quattro - Crap can, but I'm in too deep.
    2012 X3 xDrive35i - My new snowmobile.

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    Quote Originally Posted by aze30325softtop View Post
    The problem I had with similar symptoms was a bad connection at the plug(s) by the driver side headlight. After three days of chasing wires it was the wife that said "are the connections good" to which I said "of course, well maybe"... NOT. The two prong plug as i recall was bad, the socket was expanded and failed to make contact or made contact but then lost it intermitantly. I put a piece of tinfoil in the socket and it has worked great since.
    Well, when I jump K1 Pin 30 (always hot) and Pin 87 the fan spins on low so the contact is definitely there.
    This was definitely an experience and I'm glad its been semi-resolved. Still don't know why K1 Pin 86 has no ground but that should be a fairly simple patch. I also found that the fan currently installed has a new-ish (not original) resistor since the resistor has been soldered and then heat shrink wrapped. The good thing is now I have a spare resistor.

    Thanks again ricardodn.

    Quote Originally Posted by richardodn View Post
    Just to be sure, are you doing the test correctly? How about on the K6 relay between pin 85 and ground? The ground trace from K1 goes from the socket pin 86. That pin is soldered to the circuit board where the trace goes to pin 3 of C114. (C114 is the long white connector plugged into the board in your picture. Pin 3 is where the 2 brown wires are.) The K6 relay pin 85 has a jumper wire to the harness side of C114-3 and then the harness continues on to ground. If K1-86 has no ground and K6-85 does, then that indicates a board or C114 connector problem. You might just need to reflow the solder joint at K1-86.
    That is exactly the case. Ground on K6 Pin 85 is good. I checked continuity on various ground sources and all were solid. I believe the problem is with the solder point for K1 Pin 86. However, I've wasted so many days just trying to find the problem that I just want the AC to work, even if its just temporarily patched. I live in Phoenix! I need my AC! Once late fall or winter comes around I'll take the fuse box apart and resolder. For now Im just going to run a small wire to that pin.
    Last edited by Pennyw1se; 08-04-2010 at 12:43 PM. Reason: Automerged Doublepost

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    I understand about getting the AC going. I lived for 9 years in Tucson. Easiest way to do it would be to take a short small gauge wire and strip 3/8" off each end. Fan the conductors out and stick each end in the sockets for K1-86 and K6-85. Then shove the relays back in.
    "Howdy, Folks!"

    1986 Delphin 528e - Has led a hard life, 290k and still alive.
    1989 Zinnoberrot 325iX Sedan - My winter snowmobile. (Deceased)
    1998 Avus Blau 328iC - My topless summer girl.
    1999 Audi A4 Avant Quattro - Crap can, but I'm in too deep.
    2012 X3 xDrive35i - My new snowmobile.

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    Quote Originally Posted by richardodn View Post
    I understand about getting the AC going. I lived for 9 years in Tucson. Easiest way to do it would be to take a short small gauge wire and strip 3/8" off each end. Fan the conductors out and stick each end in the sockets for K1-86 and K6-85. Then shove the relays back in.
    That is exactly what I did. Success! Thanks again, man!

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    I know this is an old thread, but....

    THANK THANK THANK THANK YOU!!!!!!!

    I've been chasing down the exact same scenario as original poster. Did all the usual tests and kept coming back to some wiring issue, and the process you both ( Pennyw1se and Richardodn) documented so eloquently led to a correct diagnosis this morning on my car. Goes to show...you never know how many other people can be helped by sharing the process with others. Thanks again!!!!!

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    You're welcome.
    "Howdy, Folks!"

    1986 Delphin 528e - Has led a hard life, 290k and still alive.
    1989 Zinnoberrot 325iX Sedan - My winter snowmobile. (Deceased)
    1998 Avus Blau 328iC - My topless summer girl.
    1999 Audi A4 Avant Quattro - Crap can, but I'm in too deep.
    2012 X3 xDrive35i - My new snowmobile.

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    I don't mean to hijack this post but I have been following it and testing as you posted. The thing with mine is that I have power going to my resistor on both post but still not working so it must be the resistor????

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    If the fan should be on in normal speed such as with the AC on, the supply side of the resistor should be approximately battery or alternator voltage. The fan side of the resistor should be significantly below that; like 7-9V. If you see battery voltage on both sides, either the resistor has shorted out or there is some fault on the high speed supply side. However as long as you see voltage on the fan side of the resistor, your fan should be spinning. If not, you have a bad fan.
    "Howdy, Folks!"

    1986 Delphin 528e - Has led a hard life, 290k and still alive.
    1989 Zinnoberrot 325iX Sedan - My winter snowmobile. (Deceased)
    1998 Avus Blau 328iC - My topless summer girl.
    1999 Audi A4 Avant Quattro - Crap can, but I'm in too deep.
    2012 X3 xDrive35i - My new snowmobile.

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    Quote Originally Posted by richardodn View Post
    I understand about getting the AC going. I lived for 9 years in Tucson. Easiest way to do it would be to take a short small gauge wire and strip 3/8" off each end. Fan the conductors out and stick each end in the sockets for K1-86 and K6-85. Then shove the relays back in.
    Thanks guys been at this for a while and just did what you guys did...thank you.. Now just push the button when i see the temp rise and turn on the snowflake BAMM low speed turns on.....

    Quote Originally Posted by Pennyw1se View Post
    That is exactly what I did. Success! Thanks again, man!
    Same Here Success .....But because this was so confusing with numbers an voltmeter and touch this pin and try this fuse and read some more on the comp back and forth more numbers..lol .Did we actually fix the problem or it the ground underneath the fuse box that we still have to fix..or does it mean the resistor is bad

    Quote Originally Posted by desertcoast View Post
    I know this is an old thread, but....

    THANK THANK THANK THANK YOU!!!!!!!

    I've been chasing down the exact same scenario as original poster. Did all the usual tests and kept coming back to some wiring issue, and the process you both ( Pennyw1se and Richardodn) documented so eloquently led to a correct diagnosis this morning on my car. Goes to show...you never know how many other people can be helped by sharing the process with others. Thanks again!!!!!
    Quote Originally Posted by richardodn View Post
    You're welcome.
    Really imagine going to dealer and being charge big $$ we have to be thankful for (Penn & Rich) thanks guys.....

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