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Resolved rewire 4G63 el. connectors to fit 4G37 connectors

Posted by sacrileger, Jun 14, 2018

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  1. sacrileger

    sacrileger Proven Member

    Joined Jun 26, 2016
    Orillia, ON, Canada
    I am in the process of replacing 4g37 engine with 4g63 n/t motor. I pulled the engine bay harness from a 92 Talon which was equipped with A/C and cruise control and installed the harness in a '90 laser w/o A/C or cruise. All connectors fit except two 4g63 connectors that have more pins than the female 4g37 interior connectors.

    This one is located on the passenger side under the dashboard. The 4g63 connector has extra 2 pins:
    And this one is located under the console right by the ECU. The 4g63 connector has 6 extra pins. Not all are wired.


    How do I rewire the connectors so that they are compatible and functional?
    Last edited: Jun 14, 2018
  2. 19Eclipse90

    19Eclipse90 DSM Wiseman

    Joined Sep 29, 2003
    OKC, Oklahoma
    brads and sacrileger like this.
  3. sacrileger

    sacrileger Proven Member

    Joined Jun 26, 2016
    Orillia, ON, Canada
    This is beautiful. One of the most exhaustive and comprehensive posts. I remember going over this long, long time ago, even before I signed up as a member, for an unrelated issue to my question above, even had it bookmarked, but did not find it this time since there was no reference to 4g37 conversion and I was not up to speed as to what the specific names/functions of the two connecters I was dealing with this time was, i.e. C58, C67, etc.
    Unfortunately, even though it's not a big deal, a lot of the external links are dead now (404 error) and images not available. Also, one can figure it out but it still would be nice to have visuals (since many images from back then are now deleted) how to re-pin harness connecters, not necessarily ECU connecters, professionally. I'll look for more info on that...
    Last edited: Jun 15, 2018
  4. sacrileger

    sacrileger Proven Member

    Joined Jun 26, 2016
    Orillia, ON, Canada
    This section is for those who got this far and wanted to know how the incompatible 1990/1991+ harness connectors were mated in my particular case:
    Using the links provided by @19Eclipse90 the transplanting of the 1991+ C-58 connector on the 1990 harness was straight forward. As one can see the 1990 C-58 is a 16-pin connector and wires fill up every slot:

    The 1991+ C-58 models switched to a 18-pin connector and the pins/wires were swapped directly to the '91 C-58 connector to the exact location from which they were located on the '90 C-58 connector. The two end pin locations were left empty;


    The 1990 C-67 connector uses an 8-pin, 7-wire connector. This is what mine looked like:


    I transplanted the 1991+ C-67 14-pin connector which was used in my 5sp 1992 harness donor onto the 1990 harness:


    I transferred the wires from my 1990 female C-67 in this sequence:

    '90 C-67 -> '91+ C-67:
    pin -> pin
    2 -> 4
    3 -> 5
    4 -> 9
    6 -> 11
    7 -> 12
    8 -> 13

    One interesting thing that I encountered on my 4g37 1990 harness was a black with red stripe wire on pin #4 which is used for M/T - 2.0L Turbo Boost Gauge (gauge cluster pin 6) to ECU pin 3. I transferred this wire, although I dont have a turbo or a cluster with a boost gauge, to pin #9.
    In other words, my female C-67 14-pin connector has 6 wires going in while the male C-67 14-pin connector has 9 wires going into the connecter; as can be seen above, three wires do not have mates :D
    Last edited: Jun 21, 2018
    tametalon92 likes this.
  5. sacrileger

    sacrileger Proven Member

    Joined Jun 26, 2016
    Orillia, ON, Canada
    ...just adding some information regarding a very minor issue I have run into after I completed the conversion. Even though I dont have ABS I am dealing with ABS light ON on the gauge cluster. Perhaps someone in the future can de-pin the culprit in C45, C68, or C73 connectors:
    No ABS yet ABS light ON, WTF?
  6. fastersteve

    fastersteve Probationary Member

    Joined Jul 5, 2017
    Buda, Texas
    Since you don't have ABS you could always just pull the bulb out of the cluster.

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