Locate the primary power distribution point beneath the dashboard on the driver’s side–a black plastic fuse block with labeled slots. Pin 5 on the ignition relay (marked IG2) delivers 12V when the key turns to the “on” position; use a multimeter set to DC voltage to verify. A failing reading indicates a corroded connector or a broken trace inside the relay.
Trace the orange/black wire from the relay to the ignition coil, following it through the firewall grommet. Secure connections with crimp splices if insulation is brittle; solder joints can crack under vibration. The same wire splits near cylinder 3 spark plug–disconnect the boot and check for resistance (should read below 5 ohms). Higher resistance signals a short or internal break.
Examine the starter solenoid connections: the red/white wire carries battery voltage to the solenoid terminal, while the small purple/yellow wire triggers engagement. Clean both terminals with a wire brush if corrosion is visible–oxide buildup causes intermittent no-start conditions. Replace the solenoid if the pinion gear fails to retract after engine turnover.
For the ECM, probe the brown/red wire at pin B-6 (12V reference) and the black/white wire at pin A-12 (ground). A missing signal here disables fuel injectors. Cross-reference with a factory service manual–aftermarket diagrams often omit the alternator field circuit, which branches from the ignition switch via a fusible link.
Use heat-shrink tubing instead of electrical tape on splices; tape degrades within two years in engine bay temperatures. Label each connection with numbered flags to avoid miswiring during reassembly.
Understanding the Electrical Schematic for Your 199X SXV20 Series Sedan
Locate the main fuse box under the dashboard on the driver’s side–remove the cover by pressing the release tabs to reveal the relay cluster. Pinpoint the IGN relay (marked “IGN” or “10A IGN” in factory manuals) and verify its position against a color-coded map: red/black for power input, green/black for switched output. Trace the green/black wire from the relay socket to connector C3, a white 10-pin plug near the steering column; probe terminals 3 and 8 with a multimeter at KOEO (Key On Engine Off)–expect 11–14V. Deviations below 10V indicate corroded terminals or a failed relay.
- Strip 5mm of insulation from the green/black wire at connector C3, terminal 3.
- Solder a 18-gauge jumper to terminal 8, extending it to the ignition switch’s “ST” terminal (solid black wire).
- Secure connections with heat-shrink tubing to prevent moisture ingress–failed starts often stem from intermittent grounds at this junction.
- Replace the IGN relay if voltage drops persist; aftermarket relays (e.g., Bosch 0 332 209 150) require a 20A fuse upgrade.
Check the starter solenoid’s “S” terminal for a thin yellow/black wire–this bypasses the neutral safety switch in manual transmissions. Insert a flathead screwdriver between the solenoid’s copper contacts to test engagement; if the engine cranks, the purple/white wire (ignition feed to the PCM) is severed or the fusible link at the battery’s positive terminal has melted. Splice the purple/white wire at the PCM connector (E5, terminal 11) with a 0.5mm butt connector–factory crimps often fracture under vibration.
- Disconnect the battery negative cable before probing any circuit.
- Label all wires with masking tape at both ends prior to disassembly.
- Use dielectric grease on connectors to prevent oxidation–corrosion on the blue/white wire (tachometer signal) causes erratic RPM readings.
- Inspect the ignition coil pack’s three-wire harness: black/orange (power), black/red (trigger), and black/yellow (ground). Test resistance between the trigger and ground terminals (300–700 ohms at 20°C); readings outside this range confirm a faulty coil pack.
For intermittent no-crank conditions, focus on the security system’s immobilizer module. The gray/white wire from the transponder ring (behind the ignition cylinder) carries coded data to the module; interrupted signals trigger a 3-second crank delay. Bypass the module by bridging the gray/white wire to the pink wire (immobilizer output) at connector I16–locate this 20-pin grey plug near the firewall. Ensure the key’s transponder chip is functional; aftermarket keys (e.g., ILCO H72-PT) require programming with a Techstream interface (minimum V12.00.024).
Finding the Electrical Connector Assembly for the 5S-FE Power Distribution
Start by removing the lower dashboard panel on the driver’s side. A single 10 mm bolt holds the panel in place; once loosened, pull the panel downward to expose the fuse box and the main bundle of wires. Look for the thick black conduit that runs vertically behind the steering column–this houses the primary power leads.
The harness you need splits from this conduit near the firewall grommet, wrapped in grey corrugated tubing. Trace the bundle upward; it branches into three distinct connectors: a white plug (ignition feed), a black plug (accessory and starter solenoid), and a smaller blue plug (transponder signal). Each terminal has a unique pin count–12-way for the white, 8-way for the black, and 4-way for the blue–confirming correct identification.
For precise access, detach the knee bolster bracket using a 12 mm socket. This reveals additional loom segments previously obscured. The white connector typically sits highest, adjacent to the steering shaft, while the black connector lies closer to the firewall, slightly lower. Avoid tugging wires; Instead, depress the release tabs on each connector to separate them.
Visual and Tactile Verification
Inspect the back of each connector for factory markings: “IG1,” “IG2,” “ST,” and “ACC” on the white and black plugs, respectively. The blue plug carries no labels but is linked to the immobilizer antenna module. Use a multimeter to confirm voltage–12V should register on terminals 3 (white) and 5 (black) during key-on tests.
If corrosion is visible on the male terminals, clean with a wire brush and contact cleaner. The harness securing clip behind the instrument cluster often collects debris–clear it before reattaching connectors to ensure a tight seal. Replace any degraded conduit tape with heat-shrink tubing for long-term protection.
Associated Components Nearby
Adjacent to the main harness, locate the four-fuse block under the dash. Fuses 15 (IG1), 30 (IG2), and 10 (ECU) directly correlate to the ignition circuit. Probe fuse slots to check continuity; a blown fuse often indicates a short in the connected loom segment. The starter relay rests above the accelerator pedal–test coil resistance (80–120 ohms) if starter engagement fails.
Reassembly requires routing wires through the original grommet near the brake pedal support. Secure any loose strands with zip ties to prevent chafing against the metal frame. Tighten the dashboard panel bolt firmly–vibration can dislodge connectors over time.
Step-by-Step Breakdown of Starter Circuit Conductors and Their Markings
Locate the engine bay fuse box and remove the protective cover to expose the relay panel. The primary power feed for the cranking system is typically a thick red or red/white stripe cable terminating at the starter solenoid–verify this by tracing the line from the battery positive terminal. Use a multimeter set to continuity mode to confirm the connection between the solenoid’s “B” post and the battery; resistance should read near zero ohms. Secondary conductors often include a yellow (with blue stripe) control wire from the ignition switch, which triggers the solenoid when voltage is applied. Check for 12V here during key rotation to the “start” position.
| Conductor Role | Common Color Codes | Test Point Reference | Expected Voltage |
|---|---|---|---|
| Main power input | Red, Red/White | Solenoid “B” post | ~12V direct |
| Activation signal | Yellow/Blue stripe | Ignition switch output | 12V during crank |
| Neutral safety | Black/Yellow stripe | Inhibitor switch | 12V in “Park/Neutral” |
| Ground reference | Black | Engine block | 0V |
Isolate the neutral safety conductor (usually black with yellow stripe) at the transmission inhibitor switch–this wire must carry 12V in “Park” or “Neutral” to enable cranking. Probe the ignition switch plug: terminal 5 (often purple) should deliver 12V in “run” mode, while terminal 3 (typically white with black stripe) powers accessories. For solenoid testing, bridge the “B” post to the “S” terminal briefly–if the engine cranks, the issue lies upstream of the solenoid.
Frequent Starter Circuit Issues and Electrical Repairs for the 1997-99 V6 Sedan
Check the neutral safety switch if the engine cranks but fails to start when the key is turned–corrosion on the connector pins at the transmission housing often disrupts the circuit. Replace the faulty switch by removing the shift cable bracket, then disconnecting the two-wire plug; resistance should read 0 ohms in Park or Neutral and infinite in Drive. Clean oxidized terminals with 600-grit sandpaper and reapply dielectric grease to prevent recurrence.
Solenoid Relay Failures
Locate the starter relay under the dashboard near the brake pedal; swap it with the identical horn relay to confirm failure. A dead relay typically clicks once then cuts power–bypass it temporarily by jumping the 30 and 87 terminals with an 18-gauge wire to diagnose. Permanent repairs require a $12 OEM relay (DENSO SG174); aftermarket units often overheat due to thinner copper windings.
Examine the main fusible link between the battery and alternator if the vehicle stalls intermittently–melting at the 10-gauge junction near the radiator support indicates a short in the ECM harness. Strip back the insulation 2 cm, resolder with 60/40 rosin-core solder, and cover the repair with adhesive-lined heat shrink tubing. Failure to use flux leaves cold joints that corrode within 800 miles.