Heater System Mazda MX-6 V

DESCRIPTION

The heater assembly on all models is located in the passenger compartment. A heater control valve is used to regulate coolant flow and heat output. The heater assembly contains the heater core, heater control valve, air ducts, blower motor and intake ducts. On all models the heater systems are a blend-air type. The MX-6 and 626 may have a cable control heater control panel, or electronic control panel.

Air Flow Control

The air flow control channels the air through the ducts to the particular air vents. The desired mode is selected by moving the lever (pushing appropriate button on electronic models) on the control panel.

Air Intake Control

The air intake control is used to select either fresh air from outside or recirculated air. Operation is selected by sliding the air intake contol lever (pushing appropriate button on electronic models) to the desired function.

Temperature Control

Select desire air temperature by sliding the temperature control lever either to the right for hot or to the left for cold.

Fan Speed Control

The fan speed control lever can be moved to off ("O"), low ("1"), med/low ("2"), med/high ("3") or high ("4") position.

ADJUSTMENTS

Note. Models with electronic control panel use electric motors to control heater door operation. See TESTING in this article.

MX-6 & 626

1. Set temperature lever to cold position. Pull wire lever downward to its extreme stop. Attach air-mix wire loop onto lever.
2. Pull connecting rod lever upward to its extreme stop. Use clip to install connecting rod to fastener. Ensure proper operation of temperature control.

TESTING

Note. Tests given below are for electronic control panel models. All tests require removal of electronic control panel.

MX-6 & 626 (Electronic Panel)

Using an ohmmeter, check continuity between each terminal of 6-pin connector. See FAN SWITCH CONTINUITY (ELECTRONIC PANEL) table. (Scheme 1)

FAN SWITCH CONTINUITY (ELECTRONIC PANEL)

Scheme 1

1. Connect a battery positive lead to terminal "d" and negative lead to terminal "L". Connect a jumper wire between terminals "M" and "L". Connect a 1000-ohm resistor across terminals "B" and "O". Using a voltmeter, check voltage across terminals "B" and "O". Reading should be approximately battery voltage. (Scheme 2) Move resistor to terminals "d" and "B". Recheck voltage between terminals "B" and "O". Reading should be less than one volt.
2. Set fresh/recirc button to fresh (button out). Using an ohmmeter, check that continuity exists between terminals "N" and "L". Set fresh/recirc button to recirc (button in). Check that continuity exists between terminals "P" and "L". If test results are not as indicated, panel is defective.

Scheme 2

1. Connect a battery positive lead to terminal "d" and negative lead to terminal "L". Connect a jumper wire between terminals "I" and "L". Connect a 1000-ohm resistor across terminals "D" and "L". Using a voltmeter, check voltage across terminals "D" and "L". Reading should be approximately battery voltage. (Scheme 2)
2. Connect a jumper wire between terminals "C" and "L". Connect a 1000-ohm resistor betweem terminals "a" and "L". Check voltage between terminals "a" and "L". Reading should be approximately battery voltage.
3. Connect a 1000-ohm resistor between terminals "d" and "D". Using a voltmeter, check voltage between terminals "D" and "L". Reading should be less than one volt.
4. Connect a 1000-ohm resistor between terminals "d" and "A". Using a voltmeter, check voltage between terminals "A" and "L". Reading should be less than one volt.
5. Using an ohmmeter, check that continuity exists between terminals in all mode positions. See «MODE CIRCUIT RESISTANCE»(/mazda/mx-6/v-1986-1991/remont/heater/#heater-system) (ELECTRONIC PANEL) table.

MODE CIRCUIT RESISTANCE (ELECTRONIC PANEL)

1. Connect a battery positive lead to terminal "d" and negative lead to terminal "L". Connect a 1000-ohm resistor between terminals "Q" and "T". Set temperature control lever to center position between hot and cold.
2. Connect a jumper wire between terminals "T" and "L". Using a voltmeter, check voltage between terminals "T" and "L". Reading should be approximately battery voltage. Move voltmeter leads to terminals "Q" and "L". Reading should be less than one volt. (Scheme 2)
3. Move jumper wire to terminals "V" and "S". Check voltage between terminals "Q" and "L". Reading should be approximately battery voltage. Move voltmeter leads to terminals "T" and "L". Reading should be less than one volt.
4. Move temperature control lever to full hot position. Connect voltmeter negative lead to "L" terminal. Using positive voltmeter lead, check that voltage is higher at terminal "T" than terminal "Q". If test results are not as indicated, panel is defective.

REMOVAL & INSTALLATION

Note. Removal and installation procedures not listed are unavailable from manufacturer. However, exploded views of the systems have been provided.

Scheme 3

See also:
• TESTING
• FAN SWITCH CONTINUITY (ELECTRONIC PANEL)