How to Replace the Heater Core in a Geo Trackerby Contributor; Updated November 07, 2017
How to Replace the Heater Core in a Geo Tracker. Replacing a Geo/Chevy Tracker's heater core is a very difficult task. It requires completely removing the instrument panel from the inside of the vehicle to reach the core. If you can't get an expert to replace the core, at least consult with one to make certain you know the exact procedure before starting.
Remove the Core
Disable the Tracker's air bag system. Disconnect the negative battery cable, and then remove the Air Bag fuse, steering wheel side cap, connector positive assurance device and all inflator module connectors.
Drain the cooling system. Jack up the Tracker if necessary and place the SUV on jack stands. Crawl underneath and remove the drain plug on the bottom of the radiator, allow the coolant to flow into a container and then replace the drain plug.
Remove the instrument panel from the vehicle. This is a complex procedure, as described further in Section 2. It requires the help of an assistant and is the biggest reason you should seek expert advice.
Detach the right-side instrument panel center support and remove the evaporator (if the vehicle has air conditioning). Disconnect the SIR harness clip on the Sensing and Diagnostic Module bracket and the SDM electrical connector, and then remove the SDM bracket.
Disconnect the speedometer cable, antenna cable and floor duct from the heater case. Remove the electrical jumper harness to the air conditioning amplifier, the relay bracket and the heater assembly-to-chassis nuts from the engine compartment.
Take the heater case off the Tracker and remove the dampers and linkages from the case. Extract the heater core from the case by removing the core bracket screw and bracket.
Disassemble the Instrument Panel
Start removing the instrument panel by taking off the center console, lower steering column and glove box. Unplug the wiring harness connectors from the heater unit and blower motor assembly. Take off the connectors from the ignition switch, contact coil and combination switch.
Separate the steering column. Remove the column shaft joint bolt from under the hood and separate the steering column shaft from the lower steering shaft. Loosen all the brace bolts and (if equipped) the shift interlock cable from the ignition switch.
Undo the speedometer's cable and detach the instrument cluster and hood latch handle. Remove the radio heater control panel and heater control cables from the instrument panel. Disconnect and label all wiring harness connectors on the panel.
Loosen the panel's mounting screws and bolts. Remove the cover plates and mounting fasteners, starting with the side cover plates.
Make sure all cables, wires and hoses have been disconnected from the instrument panel. Then, have another person help you lift the panel out of the Geo Tracker.
Install a New Core
Install the new heater core into the heater case. Replace the core bracket and bracket screw, dampers and linkages to the case, and then put the case back in the Tracker.
Reconnect all the cables and connections from the heater case to the engine compartment. Proceed in reverse order, starting with the heater assembly-to-chassis nuts and bolts and finishing with the speedometer and antenna cables.
Reinsert the Sensing and Diagnostic Module, attaching all its connectors. Connect the evaporator, if you removed it, as well.
Replace the instrument panel on the Tracker. You'll need your assistant to help you position it, and then follow the reverse procedure to secure it on the vehicle.
Refill the cooling system, enable the air bag system and connect the negative battery cable. Run the engine until it reaches normal operating temperatures and then observe the climate control operation, checking for leaks in the system.