Heater System Buick Electra VI

MODEL IDENTIFICATION

Adjustment and replacement procedures in this article are referred to by model or body type. The following table lists GM division, model name and body type

GENERAL MOTORS MODELS

DESCRIPTION

System is a blend-air type in which outside air is heated and then mixed in varying amounts with cooler outside air to attain desired temperature. System consists basically of 3 parts: Blower and air inlet assembly, heater air distributor assembly and heater control assembly.

Heating components are attached to dash panel on right side of vehicle. Blower motor, air inlet assembly and coolant hoses are located on the engine side of dash panel while heater core and distributor duct are on passenger side. Since the system has no heater control valve, coolant circulation keeps heater core hot at all times. Air passing through core receives maximum heat.

Operation of blower motor is controlled by the fan switch. The motor is connected in series with the fan switch and blower resistor assembly. A 25 amp fuse is provided to protect blower circuit operation.

On all models except Nova, the heater control panel includes 2 sliding levers and a blower speed switch. Levers actuate cables that control heater mode and discharge air temperature.

The heater control panel on Nova consists of 3 sliding levers and a blower speed switch. Levers actuate cables that control airflow, fresh or recirculation air, and discharge air temperature.

Vent-Heater-Defroster Lever

Controls position of defroster door and vent-air door. In "VENT" position, blower is on (on some models) and incoming air is directed up through instrument panel. As lever is moved toward "HEATER" position, vent-air door closes, directing air into distributor assembly.

At "HEATER" position the defroster door directs almost all air to floor outlets with a small amount directed to dash registers. In the "DEF" position, air is directed to defroster outlets in dash with a small amount directed to floor outlets. Moving lever part way will split air between defroster outlets and heater outlets.

On Nova, a "BI-LEVEL" mode has been added. In this position, airflow is divided between floor outlets and instrument panel registers.

Temperature Lever

Controls position of temperature door in heater distributor. Incoming air is directed around heater core in "COLD" position or through heater core in "HOT" position. The desired outlet temperature is obtained by blending heated and unheated air through adjustment of temperature lever.

Fan Switch

Several types of fan switches are used. On models with a switch that has "LO", "MED" and "HI" positions, fan operates at any time ignition is on. Some models have a variable position switch that has "OFF" and "HI" positions and intermediate positions marked with dots.

Other models have a variable fan switch, with fan speed increasing as lever is pushed up from "OFF" toward HI" position. On Nova, fan switch has variable positions. In between "OFF" and "HI" positions are intermediate positions that are marked with lines.

Air Intake Lever (Nova)

On Nova, air intake lever allows operator to select type of air to enter system. Operator can select "FRESH" air, by sliding lever to the right or "RECIR" air, by sliding lever to the left.

VENTILATION SYSTEM

Continuous ventilation is provided when the mode lever is in the "VENT" position. Vehicle movement may create airflow through the inside of the car even when the fan is off. Some models have additional vents (not connected to heater system) that can be operated by levers under dashboard.

Scheme 1

ADJUSTMENTS

Note. Models not covered by the following procedures are equipped with self-adjusting or non-adjustable cables.

"B Bodies"

Disconnect cable end at door. Rotate door crank to close door completely. Adjust turnbuckle to allow cable end to slip over crank.

"B" & "G" Bodies

Place temperature lever at "COLD" position. Disconnect cable and rotate temperature door crank to full cold position (clockwise from top view). Adjust turnbuckle until cable loop lines up with crank. Move lever to "HOT" position and listen for door hitting stop.

Caprice

Place temperature lever at "COLD" position. Disconnect cable and rotate temperature door crank to full cold position (clockwise from top view). Adjust turnbuckle until cable loop lines up with crank. Move lever to "HOT" position and listen for door hitting stop.

TROUBLE SHOOTING & DIAGNOSIS

Refer to HEATER SYSTEMS TROUBLE SHOOTING & DIAGNOSIS article in this section.

Removal & Installation ("A", "B", "G" & "X" Bodies)

1. Disconnect battery negative cable. Remove instrument panel trim plate (right trim plate on "B" body or lower trim cover on "G" body). Remove control panel retaining screws.
2. Pull heater control out of instrument panel. Disconnect electrical connectors and control cables. To install, reverse removal procedure.

Removal & Installation ("F" Bodies)

Disconnect battery negative cable. Remove trim plate from around heater control and radio. Remove screws retaining control to console and pull heater control out so cables and electrical connectors can be disconnected. To install, reverse removal procedure.

Removal & Installation ("J" Bodies)

1. Disconnect battery negative cable. Remove glove box and right side sound panel. Disconnect control cables and heater control. Remove heater control panel trim plate and attaching screws.
2. Pull heater control out and disconnect electrical connections and cables from heater control. To install, reverse removal procedure.

Removal & Installation ("L" Bodies)

1. Disconnect negative battery cable. Remove glove box, right side sound insulator and disconnect cables at module. Remove control panel trim plate, control panel screws and pull control out.
2. Disconnect cables from control and remove cables. Disconnect electrical connection at control. Disconnect electrical connection at right side near cowl area.
3. Remove tape from main harness and disconnect. Remove left side sound insulator (if not already done). Disconnect heater harness from main harness power source connection. Remove harness. To install, reverse removal procedures.

Removal & Installation ("N" Bodies)

Remove negative battery cable. Remove radio trim plate. Remove right sound panel. Remove console extension. Remove control panel mounting screws. Disconnect electrical and vacuum connectors. Remove control panel. To install, reverse removal procedure.

Removal & Installation ("P" Bodies)

Disconnect negative battery cable. Remove front pad assembly trim plate. Remove 3 control panel retaining screws. Pull out control panel and disconnect electrical connections at blower switch. Remove control panel. To install, reverse removal procedure.

Removal & Installation ("S" Bodies)

Disconnect negative battery cable. Remove trim plate around radio and control panel. Remove control panel mounting screws. Disconnect control cable from control panel. Remove control panel. To install, reverse removal procedure.

Removal & Installation ("T" Bodies)

1. Disconnect battery negative cable. Remove center trim panel screws and radio control knobs (if equipped). Remove radio and heater control bezel (if equipped).
2. Remove screws attaching heater control to instrument panel. Pull heater control out of dash. Disconnect control cables and electrical wires. To install, reverse removal procedure.

HEATER CORE

Note. Heater core replacement is for vehicles with heater systems only. For replacement on vehicles equipped with manual or automatic A/C-heater systems, see appropriate MANUAL A/C-HEATER SYSTEMS OR AUTOMATIC A/C-HEATER SYSTEM article.

Removal & Installation ("A" Bodies)

1. Drain cooling system. On models with diesel engines, raise the vehicle. Remove instrument panel lower sound absorber. On all models, disconnect coolant hoses at heater core. Remove heater duct and heater case side cover.
2. Remove heater lower outlet. Remove 2 housing cover to air valve housing clips. Remove core retaining straps. Remove core tubing retainers and remove core. To install, reverse removal procedure and refill cooling system.

Scheme 2

Removal & Installation ("B" Bodies)

1. Disconnect battery ground. Disconnect electrical wires from blower motor and resistor. Disconnect heater core ground strap from dash. Drain radiator. Disconnect heater hoses and plug hoses and heater core tubes.
2. Remove heater core shroud screws. Remove shroud with heater core, then remove screws attaching shroud to heater core. To install, reverse removal procedure.

Scheme 3

1. Disconnect battery negative cable. Drain radiator. Disconnect heater hoses and plug hoses and heater core tubes. Remove lower right sound panel and lower right instrument trim panel.
2. On vehicles equipped with 5.0L engine, remove the ESC control module. Remove screw from lower right instrument panel carrier to cowl. Remove heater case cover screws and remove cover.
3. Remove screws from support plate and heater core. Remove heater core with support plate. To install, reverse removal procedure.

Removal & Installation ("G" Bodies)

1. Drain coolant. Remove heater hoses at heater core pipes. Remove retaining bracket.
2. Remove rear hood weatherstrip. Remove air inlet screen. (Scheme 4) Remove right side wiper arm assembly.
3. Remove all electrical connectors on upper HVAC case. Carefully cut sealer at HVAC upper case-to-firewall.
4. Remove all screws holding upper HVAC case. Remove heater core retainer screw and clamp. Remove heater core.
5. To install, reverse removal procedure. Reseal upper HVAC case at firewall to prevent water leaks.

Accumulator, Evaporator & Heater Core ("G" Body). Scheme 4

Removal & Installation ("J", "T" Bodies)

1. Disconnect battery negative cable and drain radiator. Disconnect heater hoses, plug heater core tubes and heater hoses. Remove radio noise suppression strap, heater core bracket and shroud strap or heater outlet deflector (if equipped).
2. Remove heater core cover retaining screws and remove cover. Remove heater core. To install, reverse removal procedure making sure seals are not damaged.

Scheme 5

1. Drain cooling system. Remove heater inlet and outlet hoses from heater core. Remove heater outlet deflector.
2. Remove heater core cover. Remove heater core retaining straps and remove heater core. To install, reverse removal procedures.

1. Drain cooling system. Raise & support vehicle. Disconnect heater hoses from heater core. Remove the drain tube. Lower the vehicle. Remove instrument panel sound deadening insulation.
2. Remove the lower heating duct and attached vent hoses. Remove 2 heater core covers. Remove heater core To install, reverse removal procedures.

1. Disconnect battery negative cable. Drain cooling system. Disconnect wires at heater relay, heater blower resistor, blower switch connection, heater ground strap and forward courtesy lamp socket (if equipped). Remove windshield washer reservoir.
2. Disconnect heater hose from heater core and plug hose and core openings. Remove heater core opening grommets. Remove attaching screws and remove heater case cover. Remove heater core retainer. Remove heater core. To install, reverse removal procedure.

Disconnect heater hoses from heater core. Remove 6 clips connecting lower case to upper case. Remove lower case. Remove heater core from case. To install, reverse removal procedure.

Scheme 6

1. Disconnect battery negative cable and electrical wires at blower motor. On "G" and "B" body vehicles with diesel engines, remove cowl insulator. Remove blower motor cooling tube on "F" bodies or plastic water shield from right side of cowl on "J" bodies. On "N" bodies, remove drive belt and 2 power steering mounting bolts. On "P" bodies, remove blower motor cooling tube.
2. Scribe blower motor to housing position. Remove retaining screws and remove blower motor with fan. Pry flange away from housing (if necessary) and remove blower assembly. To install, reverse removal procedure and replace sealing material at motor flange if necessary. Make sure the scribe marks made upon removal are aligned.

Removal & Installation (Nova)

Remove 3 retainer mounting screws. Remove retainer. Remove glove box. Remove duct between blower and heater assembly. Disconnect blower motor electrical connector. Disconnect control cable at blower assembly. Remove blower motor mounting screws and bolt. Remove blower motor. To install, reverse removal procedure.