Description
Product Introduction
The Woodward 37604-01 is a 6-gauge dashboard kit featuring 3-3/8″ speedometer and tachometer units alongside four 2-1/16″ supporting gauges (Oil, Water, Volts, Fuel). It utilizes NVU Phoenix Direct Drive, requiring only a single 12 Vdc connection to the speedo to daisy-chain power and data to all satellite units.
This black-face Woodward 37604-01 uses a Deco-style wrap with a plated inner ring, distinguishing it from the beige-face 37604-02. The integrated OLED window updates trip data at 10 Hz. Post-calibration needle settling hits <1.2 s from a cold start.
Key Technical Specifications
| Parameter | Value |
|---|---|
| Kit Composition | 1x 3-3/8″ Speedo, 1x 3-3/8″ Tach, 4x 2-1/16″ (Oil/Water/Volts/Fuel) |
| Major Gauge Diameter | 3-3/8 in (85 mm) |
| Minor Gauge Diameter | 2-1/16 in (52 mm) |
| Speed Range | 0-140 mph (0-240 kph programmable) |
| Tach Range | 0-8000 RPM (discrete input) |
| Oil Pressure Range | 0-100 psi |
| Fuel Level | Programmable (0-90Ω / 240-33Ω) |
| Water Temp Range | 100-250 °F (verify with OEM datasheet) |
| Voltmeter Range | 8-18 Vdc |
| Face Color | Black |
| Graphics | White / Wraparound Deco |
| Pointer Color | Red |
| Bezel | Polished stainless steel |
| Lens | Domed glass |
| Wiring | NVU Direct Drive (Daisy-chain ports) |
Woodward 47371-01
Quality Control Process (Engineer’s Perspective)
- Incoming Verification: Match NVU Woodward 37604-01 serials on both 85 mm housings and four 52 mm minors to the manifest. Inspect domed glass for lint or flaws near the plated inner accent ring.
- Live Functional Test: Energize the speedo at 12 Vdc. Feed 60 Hz to the tach input. All needles sweep full scale; verify OLED segments for dead pixels during the self-test routine.
- Electrical Parameter Test: Sweep a pot on a minor’s fuel pins using a Fluke 115. Confirm ADC linearity within 2% against the speedo reference—daisy-chain voltage drop shows as non-linear steps.
- Firmware Verification: Trigger one-mile calibration via the remote button. Photograph the OLED confirming PPM lock—well, technically it needs firmware v3.2+ for push-button config.
- Final QC & Packaging: Nest majors in die-cut foam; bag minors in anti-static pouches. Coil Direct Drive jumpers. Apply “QC Passed – 24hr Burn-in” labels with the date before boxing.
Replacement Pitfall Guide
❗ Minor Gauge Sizing: The Woodward 37604-01 uses 2-1/16″ (52 mm) holes for minors. Swapping from 3-3/8″ minors requires patching and redrilling the dash panel to the smaller standard.
❗ Daisy-Chain Topology: Signal flows Speedo Out → Tach In → Minor 1 In, etc. Forcing plugs upside down on the 52 mm backs bends center pins on the third terminal block connector.
❗ Sender Ohm Range: The fuel gauge defaults to 0-90Ω. Connecting a 240-33Ω GM sender without holding the cal button for 5s displays empty when the tank is full.
❗ Current Draw: Two majors plus four minors pull ~200 mA at 12 Vdc. Fuse for 350 mA minimum; voltage sags below 11.5 Vdc induce chatter on all six needles at idle.
❗ ESD to OLED: The speedo’s display driver is static-sensitive. Discharge to chassis ground before plugging the Packard in dry shop air—though your mileage may vary on humidity control.
Keep these in mind and you’ll cut 90% of rework time.
Woodward 47371-01
Compatibility Matrix & Benchmarks
- Woodward 37604-01 → Woodward 37604-02 : Direct — Face color swap (Black vs Beige)
- Woodward 37604-01 → Woodward 37504-01 : Needs Adaptation — 37504 lacks the 3-3/8″ Tach; this includes both Speedo & Tach
- Woodward 37604-01 → AutoMeter 6-Gauge Kit : Incompatible — Harness logic and sender ranges differ
- Sweep Response: < 1.2 seconds (0-140 mph / 0-8000 RPM step)
- Signal Input Range: 2,000 to 40,000 PPM (Speedo), 0.5-333 Hz (Tach)
- Daisy-Chain Load: < 150 mA total draw on the slave ports
