Lexus 87107-33120 Heater Radiator Unit Sub-Assembly

The manufacturer recommends removing the entire instrument panel to access the heater core, which requires disconnecting numerous electrical connectors and poses a risk of breaking delicate plastic tabs on various components, making it a challenging task for the average home mechanic. Begin by having the air conditioning system discharged by a licensed technician. Disconnect the cable from the negative terminal of the battery. Wait until the engine is completely cool, then drain the cooling system and remove the cowl assembly. In the engine compartment, disconnect the heater hoses at the firewall by removing the spring clamps and hoses, pushing the rubber seal inward to release it from the sheet metal, and plugging the heater core pipes to prevent leakage. Disconnect the refrigerant lines from the evaporator lines at the firewall. Remove the instrument panel, followed by the Powertrain Control Module and its mounting bracket, as well as the air conditioning amplifier module. In the interior, remove the left and right side defroster nozzle ducts and the heater-to-register ducts, then take out the left and right side floor ducts. Pull back the carpet to remove the carpet mounting bracket and the reinforcement brace mounting brackets at the center console, then remove the center console duct box and the left and right side air ducts. Detach the steering column from the reinforcement brace, remove the fuse and relay box from the left side of the interior, and release the wiring harness clamps and mounting bolts to carefully separate the harness from the reinforcement brace. Remove the reinforcement brace mounting nuts and bolts, then lift the reinforcement brace and the air conditioning/heater assembly from the passenger compartment, taking care to avoid breaking any plastic components. Remove the mounting bolt from the heater core inlet and outlet pipe bracket, release the clip near the firewall, and remove the screw on the retaining strap at the housing before sliding the heater core from the air conditioning/heater housing. Installation follows the reverse order of removal. Refill the cooling system, reconnect the battery, and run the engine to check for leaks and proper system operation, then have the air conditioning system recharged by the shop that discharged it.

Disconnect the electrical connectors from the quick heater assembly and slide the heater assembly out from the housing. Installation is the reverse of removal.