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.

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.

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

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

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.

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

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