Electrical
Honda swaps

12 of 12 compatibility entries for Honda.

AP2 → AP1 AP2 S2000 gauge cluster S2000 (AP2) 2004-2009 → S2000 (AP1) 2000-2003 Yes — the gauge cluster from a 2004–2009 S2000 (AP2) bolts into a 2000–2003 S2000 (AP1), but it only works after harness changes. S2KI members report different connectors between the generations and say the dash harness changed every couple of model years, so a matched set of harnesses is the cleanest route. You lose the AP1's 9,000 rpm tach scale, and the AP2's outside-temperature display will not work in an AP1. Fits VERIFIED ✓ MODS REQ. EG → EG Civic Si / EX gauge cluster (with tachometer) Civic Si (EG) 1992-1995 → Civic (EG) 1992-1995 Yes — the gauge cluster from a 1992–1995 Civic Si or EX (EG) fits a 1992–1995 Civic DX or CX (EG) and the tachometer works with no extra wiring. Honda-Tech members describe it as plug and play: the harness plugs are the same in all USDM 5th-gen Civics, so tach clusters work in non-tach cars. JDM EG6 SiR and Integra clusters are mentioned too, but members say they may need wiring changes and trimming to fit. Fits VERIFIED ✓ EM1 → EK Civic Si gauge cluster (with tachometer) Civic Si (EM1) 1999-2000 → Civic (EK) 1996-2000 Yes — the gauge cluster from a 1999–2000 Civic Si (EM1) fits a 1996–2000 Civic (EK) DX, LX, CX or HX as a plug-and-play swap. Honda-Tech members say all 1996–2000 Civic clusters interchange because every EK has the plugs for any cluster, so a tach cluster works in a car that came without a tach. EX and CR-V clusters are cheaper ways to get a tach; Si clusters cost more. Fits VERIFIED ✓ AP1 → EK S2000 digital gauge cluster with K-Tuned S2K dash converter S2000 (AP1 / AP2) 2000-2009 → Civic (EK) 1996-2000 Yes — an AP1 or AP2 S2000 gauge cluster can be fitted to a 1996–2000 Civic (EK), but it needs custom wiring and the K-Tuned S2K dash converter to make the speedometer, temperature and fuel gauges read correctly. K-Tuned lists the converter for AP1 and AP2 cluster swaps into EF, EG and EK Civics and DC2 Integras. K-Tuned's instructions cover only the converter connections and say the rest of the cluster wiring must be worked out from diagrams for your car. Honda-Tech members call it a costly swap that needs fabrication. Fits VERIFIED ✓ MODS REQ.
Accord → GE Accord horn (PN: 38100-STK-A02) Accord → Fit (2nd gen (GE)) 2009-2013 The Accord horn reuses the Fit's factory 12mm mounting bolt and plugs straight into the stock electrical connector, so it is effectively plug-and-play once the bracket is repositioned. Two punched ridges behind the hood latch act as alignment guides; seat the repositioned bracket between them and the horn sits roughly level. The mounting bolt doubles as the ground path, so the horn will not sound until it is bolted to the chassis. Access requires removing the engine-bay bulkhead cover (eight clips) and the plastic hood-latch cover. Fits VERIFIED ✓ MODS REQ.
BB → BB Digital Climate Control (DCC) system Prelude (4th gen (BB), JDM digital-climate-control-equipped) → Prelude (4th gen (BB), Australian-market manual-climate car) The DCC controller will not operate on its own. A working install requires the full sensor suite (sunlight, cabin, heater-core, evaporator and outside-air sensors), the air-mix motor, power transistor and blower high relay. Fitting the system means recovering the A/C refrigerant (and, on 1992-1993 R12 cars, converting to R134a), draining the coolant, and removing the dash, evaporator and heater unit. New firewall heater hoses are recommended (Honda 79721550000 short and 79725550010 long). The conversion can be staged: control head and manual fan/vent function first, then the A/C and heater-box work. Fits VERIFIED ✓ MODS REQ.
ES9 → DC5 EPS warning-light telltale and diagnostic wiring Civic Hybrid (ES9) 2003-2005 → RSX (DC5) 2002-2006 Wiring uses the Civic Hybrid EPS control unit Connector C pinout, which matches the EP3 Civic Si per both factory manuals. The LED negative leg ties to C6 YEL/BLU (EPS warning light) and its positive leg is powered from the RSX cluster harness: B7 Yellow on 02-04 cars or B6 Yellow on 05-06 cars, both fed by Fuse 10 under the dash. For diagnostic communication, the brown wire on the back of the DLC is spliced to C8 BRN (service check signal) and the gray wire to C20 GRY (Diagnosis-H). Result is OEM-like behavior: telltale on with ignition, off within about two seconds when no codes are stored, plus the ability to read/clear codes and reset the BCU. Fits VERIFIED ✓ MODS REQ.
DC2 → EF8 OBD1 ECU (P75) and OBD1 distributor with OBD0-to-OBD1 conversion harness Integra VTi-R (DC2 (OBD1 era)) → CR-X SiR (EF8 (OBD0; procedure applies to any OBD0 Civic/CR-X)) 1989-1991 Documented conversion of an OBD0 EF8 CR-X to OBD1 using a P75 ECU and an OBD1 distributor from an Integra VTi-R; a DC2 distributor bolted up and worked well. The car ran Crome with a stock 203 ROM for an OBD1 JDM B16A and started on the first attempt. The original single-wire O2 sensor works fine with the heater circuits disabled in the ROM. With this harness the blue 2-pin connector formerly used for setting timing (under the LH dash near the heater blower on EF8/EF9) becomes the SCS connector for OBD1 diagnostics and base-timing adjustment. Base ignition timing must be set with a timing light after conversion. A follow-up member completed the same conversion successfully with the car starting first go. Fits VERIFIED ✓ MODS REQ.
EG → EK OBD1 manual-transmission ECU (e.g. P28) with OBD2A-to-OBD1 ECU jumper harness Civic (EG) 1992-1995 → Civic (EK) 1996-1998 Yes — a 1992–1995 Civic (EG) OBD1 manual ECU such as the P28 fits a 1996–1998 Civic (EK) with an OBD2A-to-OBD1 ECU jumper harness. SpeedFactory's jumper (SFR-01-041) is listed for 1996–1998 Civic, Integra, Prelude and Accord, 1997–1998 CR-V and 1996–1997 del Sol, and accepts 1992–1995 manual ECUs including the P28, P30, P72 and P61. Moates' Honda overview says owners of 1996–2001 cars remove the stock OBD2 ECU and plug in a supported OBD1 ECU through a conversion harness, because Moates' tuning hardware supports the OBD1 ECUs. Hondata's s300 plugs into P06, P28, P30, P72, P74 and P75 ECUs. Fits VERIFIED ✓
EG → EG Power mirrors, mirror switch and door harness Civic EX (EG) 1992-1995 → Civic (manual-mirror trims) (EG) 1992-1995 Yes — the power mirrors, switch and door harness from a 1992–1995 Civic EX (EG) can be fitted to a 1992–1995 Civic with manual mirrors, with some wiring. Civic-EG forum members advise taking the complete door harness from an EX rather than making one, and the Cause For Alarm guide wires the switch to 'Ignition 2' through a 7.5 A fuse at position 16 of the under-dash fuse box. Fits VERIFIED ✓ MODS REQ.
AP1 → Prelude S2000 engine start button S2000 (AP1) → Prelude (5th gen) 1997 Working conversion documented on a 1997 (5th-gen) Prelude. The key barrel, steering lock and factory immobilizer are retained; the key is turned to ON and the button is pressed and held to crank, exactly replicating S2000 operation. The relay schematic transfers to any Honda - a follow-up contributor fitted a JDM Civic Type R start button and panel to a Civic FD as a direct bolt-in using the same diagram (adding pin 1 illumination negative and pin 2 illumination positive), and another contributor wired a button on a DC2 with a simple two-wire hookup at the ignition barrel loom (constant 12 V plus starter wire). With the ignition on, the ENGINE START legend illuminates without the parking lights on; this matches factory S2000 behavior. Fits VERIFIED ✓ MODS REQ.
AP1 → DC5 S2000 push-start (engine start) button S2000 (AP1/AP2) 1999-2009 → RSX (DC5) 2002-2006 Nothing bolts up directly. The button functions as a momentary starter trigger, not a full keyless system: the key must still be inserted and turned to ON so the immobilizer is satisfied, and the button only cranks the starter. Required extras are a 12V 30A SPDT 5-pin relay, 16-18 gauge wire, connectors, and a mounting bezel. Plug-and-play harness kits that plug into the back of the button are sold and reduce the amount of tapping required. Fits VERIFIED ✓ MODS REQ.