Wiring Specialties | 458 Danbury Rd, Unit A9 | New Milford | CT | 06776 | [email protected] LS1 To S13/S14- Engine Harness Installation Guide Thank you for purchasing the Wiring Specialties pre-made wiring harness. Please read these instructions carefully before attempting the installation. This LS1 Engine harness is designed to work with all LS1 engine platforms based off a 99-02 Fbody or GTO ECM installed in an 89-98 Nissan 240sx chassis. NOTE: For easier wiring fitment, install the harness on the engine PRIOR To installing the engine in the car! KEEP THE BATTERY DISCONNECTED WHILE INSTALLING ANY SECTION OF THE HARNESS DO NOT CONNECT THE ECU OR THE INTERIOR INTERFACE CONNECTOR UNTIL ALL ENGINE CONNECTORS HAVE BEEN INSTALLED NOTE! We will begin by connecting all the engine components first then proceed to the interior of the car to connect the ECU and the interface connectors. Feeding the harness into the car Remove the PCM covers and feed the harness through the firewall with the ECU (PCM) and the interior interface plugs leading the way. On the S13/S14 chassis the diameter of the firewall opening is small and will likely require the fan box to be unbolted to create more space for the PCM to slide through. Wire Layout Starting at the front of the engine, drape the harness over the EFI parts. Refer to the last page for complete connector identification. TIP- It is easier to lay out the LHD Driver side connectors first (this side contains the Alternator and TPS, MAF wiring connectors), followed by the passenger side, and finally the transmission drop, which should be dropped behind the V of the heads and down to the bottom of the firewall. This is a picture of the LHD Driver side section. When installing the injector connectors, use the longest branches for front injectors and the shortest ones for the rear injectors. Crank Sensor / Starter Some engine mounting kits have the headers close to the block and will require the starter to be lowered to reach the crank sensor connector. Two ring terminals are found on the passenger side of the harness. The Start Signal is the smaller, polished ring with the black wire. The Larger silver ring terminals is the Alternator power wire (red) and should be installed on the MAIN power terminal of the starter. A battery cable should be installed on the same terminals of the starter. MAKE ABSOLUTELY SURE that the two terminals do not come in contact with each other. Some GM factory battery cables will need to be filed for correct fitment. OEM 240sx battery cable can be used as well. Coolant Temperature Sensor This engine harness is designed to work with the 99+ 2-pin F-Body/GTO coolant temperature sensor. The picture shows a sample of the correct sensor required. Nissan Coolant/ Oil Gauge Adapter The Nissan coolant and oil pressure sensors are required for factory gauge cluster operation. The adapter kit offered by WIRING SPECIALTIES allows the OEM S13/14 coolant temp sensor to thread into the rear passenger head, and the OEM S13/14 oil pressure sensor into the block in the factory GM oil sensor location. The Nissan oil and coolant sensors can be found on your Nissan engine. Nissan Coolant Gauge (Non adapter) Alternatively, tap the coolant passage on the passenger side head to 12x1.25. Then, connect the 1-pin temp connector to the Nissan temp sending unit. The factory Nissan temp gauge requires a Nissan temperature sensor. This 1-pin sensor can be found on your factory Nissan engine. This sensor needs to be installed in the GM head for proper operation. Oil Pressure Sensor (Non adapter) If the adapter kit is not used, you will receive a factory GM oil pressure sensor connector. Make sure to use the oil pressure sensor designed for the oil pressure light as shown. If the connector on the harness does not fit the sensor, you can either replace the sensor or install the connector from the original GM harness . It is very easy as the terminals should simple re-pin from one connector to the other. Excludes GTO applications. Harness Ground The main engine EFI ground is located at the factory GM location on the back of the LHD Driver-side head. Use the stock bolt to secure the ground. Reverse Sensor The reverse sensor connector is located on the US passenger side of the harness and is a 2-pin black connector with a green rubber seal. Due to various engine installations, transmission tunnel may need to be modified for proper fitment of the reverse connector. Install the connector with the transmission lowered or engine out of the car. SGI-5 Speedometer The speedometer Calibration box should be setup as followed: Power-Pink Wire Ground- Black w/ White Stripe Input- Green w/ White Stripe Output 3- White All Dip Switches Down *** Refer to SGI Manual for calibration guide. Fans The Wiring Specialties harness includes relays, fuses and wiring for two electric fans and is designed to work with any factory or aftermarket style fans. The harness side connectors can be found in the front of the passenger head. The male mating connectors and terminals have been supplied along with the harness, and should be wired to the fans using the following wire layout. BLUE - Fan 1 Signal +12v GREY - Fan 2 Signal +12v BLACK - GROUND ***Make sure to test fans for airflow. Air must be pushed or pulled towards the engine. If needed, reverse polarity on the fans by reversing the fan side wires. T-56 Transmission sensors To avoid improper installation on the transmission sensors, a diagram has been provided. Again, note that laying out the harness in the early stages is crucial for proper fitment. 4L60E AutomaticTransmission Included with the automatic version of the LS Harness are two subharnesses for Park/Neutral Safety Switch and the Reverse Switch. Each has a mating end on the fusebox and must be wired into either an aftermarket gear selector switch, or directly to the transmission. (Setup may vary based on donor vehicle) Park/Neutral Safety Switch- This subharness must be wired into a gear selector switch to provide a signal to the starter in the park position Reverse Switch- This subharness must be wired into an automatic gear selector for the use of reverse lights Main Power Interface This covers both S13 and S14 chassis interfaces S14 (top picture) Plugs into the LS harness by the ECU with a white rectangular connector and into the S14 chassis harness with the white connector with a black over. Make sure that once installed, the chassis interface connector has the latch lowered to fully secure the connector in place. S13 (bottom picture) The Grey and Dark Brown 8-pin connectors are plugged into the 2 chassis connectors by the S13 US Passenger Headlight. In the passenger foot-well we find the dash connectors (white and brown). The White connector is used for the SOHC 240sx (1989 and 1990) and the Brown connector is used for the DOHC 240sx (1991-1994). Connect the correct interface plug to the dash connector behind the glove box (remove the glove box for easier install). Connect the ECU and tighten the mounting bolt lightly. Install the LS fuse box in the white connector, closest to the PCMs. S14 Wipers Connect the wiper motor plug (White for 95/96 models and Grey for 97/98 models). REMOVE the unused connector by cutting the clip off and taping up the exposed wires Wiper Amplifier & Cruise Control Make sure to connect the Wiper Amplifier (black or brown box mounted on the inside of the fender, next to the wiper motor) to the black 8-pin connector in the picture. The 4-pin grey connector is used for Cruise Control available on the SE/LE 240sx models. Just plug it into the CC module. For ABS users, please make sure to use the connector shown in this picture and not the Grey ABS connector, as they will interchange. Auto to manual Conversion Option For Auto to manual conversions, connect the two Grey extension plugs to the firewall-side of the fuse box, where 4 chassis plugs are located. Auto connectors are located on the right side of the fuse box in the image. You will need to connect the TOP 2-pin grey connector and the middle 8-pin GREY connector. Power Cable This harness has a self-contained charging cable for the alternator and starter, therefore the only cable needed is from the battery to the starter power terminal. We recommend using a 2-Gauge wire for the MAIN power supply to the starter. Fuse Box Power The fuse box needs to be wired directly into the battery, as in the factory connections. Finalize Use wire ties to ensure the wire harness does not come in contact with rotating or hot engine parts. A/C Option When the A/C option is selected you will receive a 3 pin connector wired from the ECU, which connects to the GM A/C Pressure Sensor. This pressure sensor does NOT exist on the 240sx. We recommend welding on a fitting on the high-pressure A/C line, near the firewall opening. Connect the 3-pin connector to the standard GM sensor. The second sub harness connects directly to the LS1 A/C compressor. The ground ring is connected to the front of the LHD passenger side head. Last, the blue signal wire is tapped into the factory 240sx A/C signal wire on the US driver’s side.
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