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1987 Bmw 325i Auxiliary Fan Wiring to Temp Switch

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    • Member

    TSchager

    Post Count: 7
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    I have a 1992 325ic. The air conditioner works fine but when I turn IT on, the aux cooling system fan, which should come up at low speed, does not operate. The fan also does non turn on when the engine gets hot. The resistor pack was changed in 2022 and the replacement (Magna) looks to make up in saving shape with no more of import of the wires or the housing.

    Hither's what I've tested:
    1) When the ignition is turned on and when the AC is aroused, I disconnect the 3 prong plug from the temp sensing element placed along the radiator. Bridging crosswise the black/brown and green/black causes the fan to run at high speed. Bridging crosswise the black and green/evil does not turn the fan along at low speed.
    2) Swapping the low and high speed fan relays (K1 and K6) does non deepen anything.
    3) Fuses 19 and 3 are showing 12 volts.
    4) Fuse 18 does not seem to exhibit voltage. This seems odd.
    5) For grins, I ran jumpers immediately from the battery (electropositive and negative) to the resistor pack leads ahead and behind the cooling fan. This is a black wire. there are 2 wires running to the buff, a red and a brown. If I connect the pinafore to the resistor connection 'tween it and the fan, information technology comes on at in high spirits speed (12 volts). If I connect the jumper so voltage of necessity to get ahead through the resistance, nil. Atomic number 102 voltage and the fan does not show up.

    I've done what I loved non to do until knowing what is wrong by ordering a new resistor pack and a new thermo flip for the radiator. It seems the testing I've done would have bypassed the thermo switch as part of the testing simply this is getting thwarting and mayhap throwing parts at the problem volition sooner or later solve the issue.

    Does anyone have an idea of what may embody wrong? I'd really like to turn happening my AC with the car running and have the aux fan agitate at low sped. Whatever help would be greatly appreciated.

  1. You have the etm? 6454 is the wiring plot, analyzing the circuit hopefully gets you there, but you'll probably want to look up to over the whole a/c organisation starting at 6410.

    http://wedophones.com/Manuals/BMW/1992 BMW 325i Convertible Physical phenomenon Troubleshooting Manual.pdf

    Not an issue I've had so don't know if I can tender more insight. If the agency the low speed works is the resistance serves to reduce the voltage so the lesser voltage is the fan's low or normal speed and the resistor's out, so I think it would be replacing the resistor.

    • Member

    TSchager

    Postal service Count: 7
    Likes Conventional:1
    "You take up the etm? 6454 is the wiring diagram, analyzing the electric circuit hopefully gets you there, but you'll probably want to look on all over the whole a/c system starting at 6410."

    etm? Sidesplitter, thanks for this link. I was looking the wiring diagrams to understand the flow and parts interested to trace and diagnose. Thank you!

    • Member

    TSchager

    Post Count: 7
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    ETM. Got it. Sorry to make up and so dense. PDF salvageable and page 95 printed. Time to do some checking. I for sure hope the wiring rein in didn't roll of tobacco when the original winnow resistor deep-fried when the prior proprietor had IT replaced but will check C113 and the wiring. Thanks again.
    • Member

    TSchager

    Carry Count: 7
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    MGarrison,

    Thanks a lot for the link and the information. I did the following examination based on the advice and likewise based along the conventional:
    1) removed relay K1 and jumpered crossways terminals 30 and 87. Tested the impedance of the resistance without the key on. It showed 6 ohms. Upset the key and AC turn on and got 11 volts to one side of the resistance. The other side showed zero volts.

    2) Put K1 back in the electrical relay position and continual the mental test. No voltage when the key aroused and Atomic number 89 change over also on.

    3) continual the jumper test where a positive and found wire was connected directly to the battery. A jumper was also placed between the black and K black wire of the connection to the temp sensor on the radiator to bump off the sensor/replacement from testing. The fan runs at high speeding with the jumper on the fan side of the resistance and nothing when the jump shot is attached to the first speed side of the resistor.

    I am now assuming the system has a bad relay in position K1 and likewise a bad resistor. Do these assumptions appear correct? I guess information technology's possible there are issues with the connector at C113 but I have no idea where the connective is set.

    Thanks over again for your help.

    Terry

  2. Sounds logical to me, with the caveat I'm No skillful happening electrical. The ETM has component location and views, alas sometimes the pictures aren't so great - imag index along 9000-4 (p.140) & cypher 5 on 7000-1 (p.105), that should grow you to the connector to check from there. Presumptively you saw the listing of the wiring color abbreviations on 3 (p.5), although the abbreviations are also pretty straightforward.
    • Member

    TSchager

    Post Count: 7
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    Thanks for the tip on the index finger. I did see the color abbreviations. This document is priceless. Thanks again for sending the inter-group communication.
  3. If you come your ain sustentation, the E30 Bentley manual is worth having - it's not perfect, some how-to's are missed or glommed-over in some instances, merely whatever it doesn't cover pot most-likely be institute searching the 'net -

    http://www.bentleypublishers.com/bm...bmw-3-series-e30-1984-1990-fix-hand-operated.html

    I Hope your a/c fix works out to constitute as caudate as the relay & resistor!

    • Extremity

    TSchager

    Post Count: 7
    Likes Acceptable:1
    Yup. Got 2 of them. Single in the railway car and the other in my office for reference. The Bentley doesn't come close to the detail the ETM provides. Some are great resources though. Thanks again.
  4. Yea, Bentley has some wiring diagrams, simply not that one; got Maine curious to depend, Bentley does have a chart of splice and connector locations, just no pics like the ETM. I don't know World Health Organization hosts that wedophones site, but it's adroit, has been there for a long time in real time & thankfully still is. Glad to follow of any help!
    • Member

    TSchager

    Position Count out: 7
    Likes Received:1
    Well, the diagram thickens. IT looks like the machine has issues with dregs at the mix/relay panel (Relay K1). I've changed out the resistor (it was bad) and the temporary worker detector (low speed trigger was bad). Turns out on that point's a link happening Bimmerforms that talks about this problem.

    The link is: https://World Wide Web.bimmerforums.com/forum/...ighlight=help with AC auxilliary Fan K1 relay. My pin 86 on the K1 relay was not going to ground. I created a jumper to K6 Pin 85 and fanned the leads extinct like IT said in the blog.

    My car had exactly the same problem with pin 86 on K1, where the ground got divided somehow over time. Low speed operation on some temp and Ac operation now work. Overlooking cannonball along works too.

    Finally, the fix involved replacing the temp switch on the radiator, the resistor and the pinny. I suspect both the switch and resistor were bad due to a atrocious/failing ground on pin 86 that caused them to neglect but we'll never make love. Bottom credit line is that it is fixed thanks to your help and that of the link over on BimmerForums.

    This ought to equal a sticky on the CCA website and assembly because others have and will jar against this. Debugging is a lot of forg.

    Thanks again!

    Terry Schager

  5. Kudos on working it through &A; getting it square - not rich w/ multiple issues like that!

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1987 Bmw 325i Auxiliary Fan Wiring to Temp Switch

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