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Best Practices on Wiring a Transmission Cooler Fan?

Discussion in '3 and 4-Series' started by matreyia, Jul 25, 2017.

  1. matreyia

    matreyia Lieutenant

    Messages:
    585
    Ride:
    335i e93
    Hi Everyone,

    I would like to ask if any of you know the best practice of wiring an auxiliary cooling fan in the fog light area. Can we just use the positive lead in the engine compartment and integrate that lead with the aftermarket thermostat and resistors which come with the fan?

    Or should we always take time and effort to literally make a new connection inside the fuse box and do god knows what to where in order to avoid electrical gremlins down the road after install?

    I have the thermostat that fits directly into the Vader Solutions ATF cooler fittings, and a resistor switch and a 7 inch fan that I need to add for cheap insurance on the ATF temps.

    Thanks in advance for your thoughts.

    VT
     
  2. doublespaces

    doublespaces Administrator

    Messages:
    6,357
    Location:
    AZ
    Ride:
    2009 E93 335i
  3. matreyia

    matreyia Lieutenant

    Messages:
    585
    Ride:
    335i e93
    Often times, a general EE is not equipped to answer specific BMW best practices questions. I don't know if this is one of those times. For example, one would think that buying a battery from Walmart to replace the stock battery would be straight forward...until one realizes that it must meet certain criteria and must be digitally coded/registered to the specific car...and that it is not recommended to piggy back additional power lines directly from the battery terminals where the stupid complicated looking harness resides. Doing this supposedly gives rise to enough voltage variation that inexplicable electrical gremlins begin to rear their ugly heads.

    VT
     
  4. Omar@VaderSolutions

    [email protected] Sergeant Vendor

    Messages:
    319
    Location:
    NY & AZ
    Ride:
    N54 135i & N54 335i
    i made a limited amount of trans cooler harnesses that were PnP... time consuming and not really worth it financially ... i wont advertise it but i can do it for anyone just takes time
     
  5. doublespaces

    doublespaces Administrator

    Messages:
    6,357
    Location:
    AZ
    Ride:
    2009 E93 335i
    Price?
     
  6. Omar@VaderSolutions

    [email protected] Sergeant Vendor

    Messages:
    319
    Location:
    NY & AZ
    Ride:
    N54 135i & N54 335i
    unsure..... ill think of one when im back in town
     
  7. Kenjermen

    Kenjermen Corporal

    Messages:
    227
    Location:
    N las vegas NV
    Your fine just taping into the dog light switch for power. I ran mine like this for awhile with no issues. If you want to give yourself warm fuzzies you can install a inline fuse and call it a day. I ran a switch for the fan inside the car.
     
  8. matreyia

    matreyia Lieutenant

    Messages:
    585
    Ride:
    335i e93
    I prefer using the main power constant line, then the thermostat wire to the thermostat, then the negative to ground,...for the life of me, it appears NOBODY knows where to find the ignition wire in the engine compartment, or any accessory wire, or remote wire anywhere. I been looking for two weeks daily.
    Found some vague tales of a Green wire in the CAS...until you look there, and you see multiple green wires - then you know, don't fool around there if it's not definite.

    So I am at a loss.
     
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