Announcement

Collapse
No announcement yet.

Need help with M3 cluster swap in 325i. (SOLVED)

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Need help with M3 cluster swap in 325i. (SOLVED)

    Fuel level gauge does not seem to work. I have done the following;

    Swap circuit board with the known working from the 325i into the M3 cluster. Swap the known working fuel gauge in the M3 cluster. Still doesn't work.

    Tried with both coding chips still same result.

    Checked everything on both circuit boards and everything is matching.
    Tested the ohms on both 325i and M3 gauges are the same.

    Swap the M3 gauge into the 325i cluster and everything works.
    Put back original 325i cluster and everything works.

    I did not hook up the oil temp gauge because it appear to be stand alone gauge. TIA.
    Last edited by dsphil; 04-06-2019, 10:01 AM.
    sigpic
    327is
    325es
    325es
    318is
    Fiesta ST
    E46 M3

    #2
    Its a bit hard to decipher exactly what you did to troubleshoot but its looking like your main circuit board in the M3 cluster has failed. The standard and M3 main circuit boards are very close to being identical and can swap interchangeably except the M3 has provisions for rear aux lights.

    If your 325i board is confirmed good and your M3 fuel gauge is confirmed good, then use those parts in the m3 cluster and all should work good. Alternatively, there are only three connections on the fuel gauge circuit, power, ground and signal. One of those traces from the gauge to the connector sockets is probably cracked. Keep in mind that when you are troubleshooting, testing for ohms may not work.

    This is because the continuity may be tested as closed when the cluster is not powered on. However, once electrical current flows through the circuit, the metal can heat up and expand causing an open circuit that was not otherwise there. Therefore, it would be more better to test your circuits while powered on because they are under load.
    Owner - Bavarian Restoration
    BMW and European Electronics Repair and Restoration
    www.BavRest.com
    My Feedback Thread
    Our Facebook!
    Follow our Instagram!

    Comment


      #3
      Solved. Break out the wiring diagrams and turns out standard late models use 2 fuel level sending unit where M3 use 1. I bypassed the secondary sending unit and it works fine. The whole time my tank was less than 1/4 and the gauge just didn't register.
      sigpic
      327is
      325es
      325es
      318is
      Fiesta ST
      E46 M3

      Comment

      Working...
      X