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    Results 1 to 10 of 10
    1. #1
      Join Date
      Sep 2017
      Posts
      99

      LS3 Wire Harness Connectors

      I bought a cruise and connect package from GM and there are some connectors im not familiar with for my LS swap Chevelle.

      ENGINE HARNESS:
      1. What is the VEH SPD vehicle speed connector used for on LS swap. I plan on using gps speedometer. Does the PCM need this for anything?


      2. GEN connector is only one 16 gauge wire that seems to plug into the alternator. The alternator has 4 pins but the connector only has one wire. The alternator has a single connection on the back that I assume will be for the main harness in the car and for starter solenoid and battery charging.


      3. I have an EOP connector that I assume is for engine oil pressure. Is this actually needed. I will have aftermarket gauges with one for oil pressure. My understanding is if the sensor does not detect oil pressure it will not allow the fuel pump to run??? Is this actually needed or has this been deleted in the programming

      TRANSMISSION:
      Looking at the photos, are any of these wires actually needed. I have a 4L75E electronic tranny.

      1. Can I use the rpm wire for my speedhut gauge?

      thnaks so much for any help!!!

      Perry
      Attached Images Attached Images        

    2. #2
      Join Date
      Nov 2006
      Location
      Mountain Springs, Texas
      Posts
      4,488
      Country Flag: United States
      All of this is covered in the documentation you got with your package but here are some answers to the best of my memory embedded below:

      Quote Originally Posted by Zombie666 View Post
      I bought a cruise and connect package from GM and there are some connectors im not familiar with for my LS swap Chevelle.

      ENGINE HARNESS:
      1. What is the VEH SPD vehicle speed connector used for on LS swap. I plan on using gps speedometer. Does the PCM need this for anything?

      It is an output intended to drive a speedometer. If you don’t need it don’t connect it.

      2. GEN connector is only one 16 gauge wire that seems to plug into the alternator. The alternator has 4 pins but the connector only has one wire. The alternator has a single connection on the back that I assume will be for the main harness in the car and for starter solenoid and battery charging.

      Correct

      3. I have an EOP connector that I assume is for engine oil pressure. Is this actually needed. I will have aftermarket gauges with one for oil pressure. My understanding is if the sensor does not detect oil pressure it will not allow the fuel pump to run??? Is this actually needed or has this been deleted in the programming

      I used the stock oil pressure sensor so I can’t help you on this one. Check your documentation.

      TRANSMISSION:
      Looking at the photos, are any of these wires actually needed. I have a 4L75E electronic tranny.

      The A/B wire enables selection between economy and sport transmission modes. Check your documentation.

      The brake wire is normally connected to the brake light switch. Again check your documentation.

      The manual shift connections are for tap shifters if i recall. If you don’t have tap shifting then don’t use them.

      1. Can I use the rpm wire for my speedhut gauge?

      Yes. You will likely need a 4.7kohm pull-up resistor connected to 12 volts.

      thnaks so much for any help!!!

      Perry
      1969 Camaro - LSA 6L90E AME sub/IRS
      1957 Buick Estate Wagon
      1959 El Camino - Ironworks frame
      1956 Cameo - full C5 suspension/drivetrain
      1959 Apache Fleetside

    3. #3
      Join Date
      Aug 2004
      Location
      Jacksonville, FL
      Posts
      1,651
      Country Flag: United States
      The VSS plug is critical for an auto I believe. The GM OP sensor does work with CAN gauges, using them on my DD gauges on my LS3 GMPP harness. Are you using the bulkhead connector for the trans signals?
      Chris
      1968 Chevy Camaro SS
      LS3/T56 DSE suspension


    4. #4
      Join Date
      Sep 2017
      Posts
      99
      Thanks guys, this was very helpful!!

      Chris,
      Does the VSS sensor plug into the tranny? If it does, then I shouldn't have an issue using my gps speedometer, right?

      Perry

    5. #5
      Join Date
      Aug 2004
      Location
      Jacksonville, FL
      Posts
      1,651
      Country Flag: United States
      Perry, yeah you need to plug the VSS plug into the transmission. Which TCU are you using? You should be able to use the bulkhead connector and connect that to your TCU. The PCM needs the vss so Hank in an auto application. If you are using a GPS antenna for your speedo then it will be totally separate. Which gauges are you running?
      Chris
      1968 Chevy Camaro SS
      LS3/T56 DSE suspension


    6. #6
      Join Date
      Nov 2006
      Location
      Mountain Springs, Texas
      Posts
      4,488
      Country Flag: United States
      My mistake on vehicle speed connector. I thought you were referring to the VSS output, not the VSS input connector. Sorry for the confusion.

      VSS output is the orange speed wire in your pic.

      Don
      1969 Camaro - LSA 6L90E AME sub/IRS
      1957 Buick Estate Wagon
      1959 El Camino - Ironworks frame
      1956 Cameo - full C5 suspension/drivetrain
      1959 Apache Fleetside

    7. #7
      Join Date
      Sep 2017
      Posts
      99
      Chris,
      The gauges I'm using are speedhut model GRM338-6KITGPS-01. I slap have couple of other queries:

      1. In the photo you can see a connector with a blue end. This is the EOP engine oil pressure. Since my gauge kit comes with an oil pressure sensor, how do I make the gauge work. Does the PCM need to see oil pressure for it to work.

      2. The last photos show a number of connections. The top one is the OBDII port, pedal is obvious. What is the MIL connection for and finally, can I use any unused switched power sources for the IGN SW connection.

      Thanks again for the help!!
      Perry
      Attached Images Attached Images    

    8. #8
      Join Date
      Nov 2006
      Location
      Mountain Springs, Texas
      Posts
      4,488
      Country Flag: United States
      MIL is the malfunction indicator light or check engine light.

      Any line that is hot while cranking can be used. The wires are generally pink...

      Don
      1969 Camaro - LSA 6L90E AME sub/IRS
      1957 Buick Estate Wagon
      1959 El Camino - Ironworks frame
      1956 Cameo - full C5 suspension/drivetrain
      1959 Apache Fleetside

    9. #9
      Join Date
      Aug 2004
      Location
      Jacksonville, FL
      Posts
      1,651
      Country Flag: United States
      Perry, GMPP pcm does not need the oil pressure sender to operate. Just use the OP sender that came with your gauges. If your sender is not metric, you will have to get an adapter fitting. Same for the temp gauge. The PCM does need water temp, most use the drivers side head sensor for the PCM and the pass side for your new gauge sender. That MIL wire is the light for your check engine light. The PCM sends a “ground” signal when it comes on. What you have to do is connect one side of whatever light/led you are going to use with ign power and then the MIL wire on the other side of the light circuit.
      Chris
      1968 Chevy Camaro SS
      LS3/T56 DSE suspension


    10. #10
      Join Date
      Sep 2017
      Posts
      99
      Fantastic everyone. Really appreciate the help. I am good to go.

      Perry







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