Description
Product Introduction
The Woodward 37504-01 is a 5-gauge dashboard kit centered on a 3-3/8″ programmable speedometer and four 2-1/16″ supporting gauges. It runs on NVU Phoenix Direct Drive, requiring only one 12 Vdc tap on the speedo to distribute power and data to the satellite units via daisy-chain.
This black-face Woodward 37504-01 uses a period-correct Deco style with a plated inner accent ring. The OLED trip window updates at 10 Hz. Needle settling completes in under 1.2 seconds from a cold 12 Vdc power-up.
Woodward 47371-01
Key Technical Specifications
| Parameter | Value |
|---|---|
| Kit Composition | 1x 3-3/8″ Speedo, 1x 2-1/16″ Oil, 1x 2-1/16″ Water, 1x 2-1/16″ Volts, 1x 2-1/16″ Fuel |
| Speedo 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) |
| 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 | 10-16 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) |
Quality Control Process (Engineer’s Perspective)
- Incoming Verification: Match NVU Woodward 37504-01 serials on the 85 mm speedo and four 52 mm minors to the packing list. Inspect domed glass on the speedo for trapped debris near the inner accent ring.
- Live Functional Test: Energize the speedo at 12 Vdc. Inject 60 Hz signal. The speedo sweeps; check minor gauge backlights and OLED segments for dead pixels during the self-test routine.
- Electrical Parameter Test: Sweep a pot on the fuel sender pins using a Fluke 115. Verify ADC linearity within 2% against the speedo reference—daisy-chain voltage drop shows as non-linear steps here.
- Firmware Verification: Trigger one-mile calibration via the remote button. Photograph the OLED confirming PPM lock—well, technically it needs firmware v3.2+ for the push-button method.
- Final QC & Packaging: Nest the speedo 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 37504-01 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 → Minor 1 In → Minor 2 In, etc. Mixing up the plug orientation on the 52 mm backs bends the center pins on the third terminal block.
❗ Sender Ohm Range: The fuel gauge defaults to 0-90Ω. Connecting a 240-33Ω GM sender without holding the cal button for 5s shows empty when the tank is full.
❗ Current Draw: One speedo plus four minors pulls ~180 mA at 12 Vdc. Fuse for 300 mA min; voltage dips below 11.5 Vdc cause chatter on all five 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 levels.
Keep these in mind and you’ll cut 90% of rework time.
Woodward 47371-01
Compatibility Matrix & Benchmarks
- Woodward 37504-01 → Woodward 37504-02 : Direct — Face color swap (Black vs Beige)
- Woodward 37504-01 → Woodward 37332-01 : Needs Adaptation — 37332 includes a 3-3/8″ Tach; this uses 2-1/16″ minors
- Woodward 37504-01 → AutoMeter 4797 : Incompatible — Harness logic and sender ranges differ
- Sweep Response: < 1.2 seconds (0-140 mph step change)
- Signal Input Range: 2,000 to 40,000 PPM (Speedo)
- Daisy-Chain Load: < 130 mA total draw on the slave ports
