Odometer readings are displayed from by data relayed by the PCM. It is fully electronic and can only be manipulated by a specialized licensed repair facility. The Gauge cluster also has a built in memory so even if the PCM is changed it will not adjust the odometer display.
this is usally caused by your speed censor is gone it should be located on top of transmission drivers side of car it is the one with 2 wires plugged into it.
If the speedometer is not working but the odometer is, I would suspect the dash cluster is at fault. If both speedometer and odometer are not working I would suspect the speed sensor on the transmission is at fault.
Your speedometer, odometer, and cruise control quits working; That's all. It happened to me when I replaced the transmission on my Altima and the two wires came out of the connector.
If both the speedometer and odometer stopped working it is probably the speed sensor in the transmission gone bad. If only the speedometer quit you may have to replace the dash cluster with a reconditioned unit.
There's a speed sensor towards the back and top of the transmission (not to be confused with wheel speed sensors, which are part of the ABS system). Either that's gone bad, or there's a fault in the wiring somewhere between that speed sensor and the engine ECM.
vss sensor
There are heater-resistance wires in the glass of the back windshield.
The 2003 Trailblazer speed sensor is mounted on the transmission. It is on the passenger side of the output end.
Have your mechanic check the speedometer cable connections. They no longer use a cable. It is electronic. If the speedometer is not working but the odometer is, the problem is in the dash cluster. If both the speedometer and odometer are not working, the speed sensor in the transmission may be at fault.
no distributor or spark plug wires its a coil pack on the top of the engine.
A eaton fuller 18 speed roadranger gearbox is used
You probably mixed up the firing order.