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Short Summary
Main recommendation: If the odometer does not spin but the speedometer works, the likely cause is brittle plastic gears inside the gauge cluster, which can be replaced after removing the cluster from the dashboard. The video also covers replacing the vehicle speed sensor when both the speedometer and odometer fail, and swapping the dash bulbs for LEDs during the job.
Key Points
- Odometer failure with a working speedometer points to the plastic odometer gears breaking (the worm gear and driven gear), not the speed sensor.
- If both the speedometer and odometer fail, the vehicle speed sensor is the more likely culprit; on this car it sits at the rear of the transmission, held by one bolt.
- Modern cars use a vehicle speed sensor that converts the spinning mechanical signal into an electrical signal sent to the dash, so the odometer works on digital and analog gauges alike.
- The repair is shown on an analog dash with physically spinning numbers; digital dashes work differently.
- The replacement gears used in the video come with a lifetime warranty, are inexpensive, and use a better quality plastic so the repair hopefully won't need to be redone.
Details Worth Noting
- Concrete instructions: Disconnect the negative battery terminal before working on the dash. Remove the two top dash bolts (T15/T20 Torx, or a 7 mm socket). Pull the headlight knob out, turn it to reveal the slot, and pry the switch out with a flat-head screwdriver. Pop the plastic gauge bezel free from its clips at the left and right corners. Remove the four cluster screws, pull the cluster out, release the wiring harness clip, and disconnect the connectors. Remove the gold-colored screws on the cover (T15 Torx or 5.5 mm socket), blow out any dust with compressed air, and pry out the three gauge sections. Remove the motor by lifting its blue plastic clip slightly and twisting. Pry out the broken black driven gear and clear all fragments. Install the new white driven gear so it meshes with the red gear. Pry off the old worm gear and slide on the new one, pushing it nearly to the base but leaving a small gap so it does not bind. Reinstall the motor, then reassemble in reverse order, making sure to fit one screw before the plastic cover goes on. Clean the cover with a microfiber cloth and warm water, not paper towel. Snug the eight edge screws without overtightening, since they thread into plastic. Replace the five large black-knob bulbs with LEDs; the beige knobs are indicator lights and were left as-is.
- The video shows the speed sensor is replaced by removing one bolt at the rear of the transmission.
- LED bulbs may be polarity-sensitive (in this case the bulbs used weren't); after installing, power the cluster and confirm each bulb lights, and if one does not, flip it and reinsert.
- Reconnect the battery to test; the odometer and trip odometer should spin when the car moves.
Bottom Line
When the speedometer works but the odometer does not, expect broken plastic gears, which are a relatively inexpensive, accessible DIY fix requiring only basic hand tools and careful reassembly.
