S14 240SX Auto to Manual conversion: Electrical Connections




Note: This page orginally was written by 'cwilfert' and is no longer hosted, so I have decided to host it here for reference.






 
Required Tools Additional Notes
Wire Cutters  
Wire Stripers  
Wire Crimpers  
Wire Connectors
  • Butt Splice Connectors For 18-22 Gauge Wire
  • One 12 Gauge Butt Splice Connector Needed
  • One 12 Gauge Ring Terminal Connector Needed
16 Gauge Wire
  • Various Colors Make Things Easier
Wire Ties
  • To Wrap Up Wire
Wire Loom
  • To Protect Exposed Wires Under The Car
Ratchet
  • Suggest 1/4" Drive
10mm Socket
  • Suggest 1/4" Drive

Starting System


Follow These Steps In Order Additional Notes Reference Pictures
Complete Starting Circuit
  • The Top Connector Of The Group Of Wiring Harnesses From The Automatic Transmission Must Be Jumpered Together In Order For The Car To Start
  • Located Behind The Fuse Box In The Engine Compartment
Jumper Connectors Together
  • Use A 12 Gauge Butt Connector To Connect The Harness Wire Together
  • Plug The Connector Into The Socket
  • The Car Will Now Start
  • WARNING: THE CLUTCH DOES NOT HAVE TO BE DEPRESSED IN ORDER TO START THE CAR => THE CAR CAN BE STARTED IN GEAR AND WILL LURCH

 

NOTE:  THE MANUAL TRANSMISSION I USED IN THE CONVERSION HAD THE M/T FACTORY HARNESS CONNECTED TO IT.
              ALL REFERENCES TO CONNECTING WIRES ARE MADE IN REGARDS TO USING FACTORY WIRING HARNESS
              CONNECTORS.

Backup Lights


Follow These Steps In Order Additional Notes Reference Pictures
Complete Backup Lights Circuit
  • The Third Connector Down Uses The Black And Green Wires (A/T Harness Side) To Connect To The Reverse Switch On The Manual Transmission
Connect Reverse Switch Light Wires
  • The Reverse Lamp Switch Is The Front Switch On The M/T
  • Connect The Reverse Lamp Switch Harness Connector To The Third Connector Down Wires
  • It Does Not Matter Which Wire On The Reverse Lamp Switch Connects To Which Wire On The Third Connector Down.  The Switch Only Completes The Circuit Wire The M/T Is In Reverse
  • Cover The Wires With Wire Loom
Connect Wiring Harnesses
  • Plug The Wiring Harness Into The Transmission And Into The Connector Located In The Engine Compartment
  • The Backup Lights Will Now Come On When You Put The Car In Reverse When The Key Is In The Ignition



 

Neutral Position Switch


Follow These Steps In Order Additional Notes Reference Pictures
Complete Neutral Position Switch Circuit
  • WARNING: THIS STEP REQUIRES CUTTING INTO YOUR ECM WIRING HARNESS
Disconnect ECM Wiring Harness
  • Turn Ignition Switch Off
  • Disconnect Negative Battery Terminal
  • Disconnect ECM Wiring Harness
  • Remove ECM Wiring Bundle Cover
Find The Neutral Position Switch Wire (R/G)
  • Look At The Wire Side Of The ECM Harness
  • From The Connector Bolt The Red/Green Neutral Position Switch Wire Is Located On The Top Row 3 Wires To The Right
  • Once You Find The Correct Wire Mark It
Run Wires From The M/T Neutral Position Switch To The ECM
  • Drill A Hole Directly In Front Of The Shifter To Run Wire Through From The Transmission
  • Use A Rubber Grommet On The Hole To Protect The Wires
  • Run Wires From The Transmission To The ECM
  • Run 1 Black Wire And 1 Green Wire


Connect Neutral Position Switch Wires To The M/T
  • The Neutral Position Switch Is The Rear Switch On Top Of The M/T In Front Of The Shifter Housing
  • Connect The Black Wire On The Switch Harness To The Black Wire From The ECM
  • Connect The Green/Orange Wire On The Switch Harness To The Green Wire From The ECM
  • Cover The Wires With Wire Loom
Connect Wiring Harness
  • Plug The Wiring Harness Into The Transmission
 
Connect Neutral Position Switch Wire To The ECM
  • Cut The Wire From The ECM You Marked Earlier
  • Connect The Green Wire From The M/T Neutral Position Switch To The Red/Green Wire Coming From The ECM Wiring Harness
 
Connect Neutral Position Switch Wire To Ground
  • NOTE: COMBINE THIS STEP WITH THE SAME STEP UNDER CONNECT 5TH POSITION SWITCH WIRE TO GROUND
  • Use The Body Ground Connector Behind The ECM
  • Put A Ring Terminal Connector On The Black Wire From The M/T Neutral Position Switch
  • Connect The Ring Terminal To The Body Ground

 

5th Position Switch


Follow These Steps In Order Additional Notes Reference Pictures
Complete 5th Position Switch Circuit
  • WARNING: THIS STEP REQUIRES CUTTING INTO YOUR ECM WIRING HARNESS
Disconnect ECM Wiring Harness
  • Turn Ignition Switch Off
  • Disconnect Negative Battery Terminal
  • Disconnect ECM Wiring Harness
  • Remove ECM Wiring Bundle Cover
Find The 5th Position Switch Wire (R/B)
  • Look At The Wire Side Of The ECM Harness
  • From The Connector Bolt The Red/Black 5th Position Switch Wire Is Located On The Second Row Down 3 Wires To The Left
  • Once You Find The Correct Wire Mark It
Run Wires From The M/T 5th Position Switch To The ECM
  • Drill A Hole Directly In Front Of The Shifter To Run Wire Through From The Transmission
  • Use A Rubber Grommet On The Hole To Protect The Wires
  • Run Wires From The Transmission To The ECM
  • Run 1 Black Wire And 1 Yellow Wire


Connect 5th Position Switch Wires To The M/T
  • The 5th Position Switch Is The Middle Switch On The Side Of The M/T In Front Of The M/T Cross Member
  • Connect The Black Wire On The Switch Harness To The Black Wire From The ECM
  • Connect The Yellow/Blue Wire On The Switch Harness To The Yellow Wire From The ECM
  • Cover The Wires With Wire Loom
DO NOT CONNECT THE WIRING HARNESS THE THE TRANSMISSION - EXPLANATION AT THE END
Connect 5th Position Switch Wire To The ECM
  • Cut The Wire From The ECM You Marked Earlier
  • Connect The Yellow Wire From The M/T 5th Position Switch To The Red/Black Wire Coming From The ECM Wiring Harness
 
Connect Neutral Position Switch Wire To Ground
  • NOTE: COMBINE THIS STEP WITH THE SAME STEP UNDER CONNECT NEUTRAL POSITION SWITCH WIRE TO GROUND
  • Use The Body Ground Connector Behind The ECM
  • Put A Ring Terminal Connector On The Black Wire From The M/T 5th Position Switch
  • Connect The Ring Terminal To The Body Ground
  • The Reason That You Do Not Connect The 5th Position Switch Harness To The Transmission At This Time Is That The ECM Is Different For Automatic Transmission And Manual Transmission Cars.  Pin 7 (Red/Black Wire) On The A/T ECM Is The OBDII Diagnostic Line From The A/T Control Unit.  The Car Will Run Without The 5th Position Switch Being Connected To The ECM.

 

Automatic Speed Control Device (ASCD) Clutch Cancel Switch


Follow These Steps In Order Additional Notes Reference Pictures
Complete ASCD Clutch Cancel Switch Circuit
  • WARNING: THIS STEP REQUIRES CUTTING INTO THE ASCD BRAKE CANCEL SWITCH WIRE
 
Disconnect ASCD Brake Cancel Switch
  • Disconnect Left Harness On Brake Pedal
  • The ASCD Connector Is Blue
 
Cut G/B Wire On The ASCD Brake Cancel Switch
  • Cut The Green/Black Wire On The ASCD Brake Cancel Switch
  • Connect A Butt Splice Connector To Each Half
Connect Wires To The ASCD Clutch Cancel Switch
  • Connect A Butt Splice Connector To Each Wire Coming From The ASCD Clutch Cancel Switch Connector (Green/White, Green/Black)
Jumper Switches Together
  • Connect The Two Switches Together With A Length Of Wire
  • The ASCD Clutch Cancel Switch In Now Wired In Series With The ASCD Brake Cancel Switch
  • Covers The Wires With Wire Loom
Connect Wiring Harness
  • Plug The Wiring Harnesses Back Into Their Respective Connectors
  • The ASCD Clutch Cancel Switch Will Now Work
 

 

Instrument Cluster O/D Off Bulb


Follow These Steps In Order Additional Notes Reference Pictures
Remove O/D Off Bulb
  • This Step Is Not Required
  • The O/D Off Bulb Is Located On The Right Side Of The Instrument Cluster (Looking At Cluster From Behind)
  • The O/D Off Bulb Is The Second Bulb From The Right On The Top Row
  • Remove The O/D Off Bulb By Turning It Counter Clockwise