If the dspeedometer is working but odometer is not, it is a fault with the meter cluster as both circuits are linked.
ENGINE COOLANT TEMPERATURE (ECT) GAUGE TEST
CAUTION: Turn ignition switch to OFF position before gauge pointer reaches "H" mark, or ECT gauge may be damaged.
1. Check fuse No. 20 (20-amp), located in underdash fuse/relay box in left kick panel. Turn ignition switch to OFF position. On 3.5RL, remove engine cover. Disconnect Yellow/Green wire from Engine Coolant Temperature (ECT) sending unit. Sending unit is located in middle of engine.
2. Using a jumper wire, ground ECT sending unit Yellow/Green wire. If ECT gauge pointer does not move, check for poor connections or open in Yellow/Green wire between ECT sending unit and ECT gauge. If wire is okay, replace ECT gauge. If ECT gauge pointer moves, check ECT sending unit.