GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1998 🢒 Metro 🢒 HVAC 🢒 HVAC Systems - Manual 🢒 Heat Excessive

Heat Excessive Heat Mode

Step

Action

Value(s)

Yes

No

1
  1. Set the mode to HEAT.
  2. Set the blower speed to HI.
  3. Set the temperature control to full HOT.
  4. Turn the ignition switch to ON.
  5. Inspect for airflow out of the heater outlet.

Is little or no air flowing from the heater outlet?

--

Go to Step 3

Go to Step 2

2

Turn the blower speed from OFF to LO, from Lo to MED-LO, from MED-LO to MED-HI, from MED-HI to HI and then back to OFF.

Does the blower motor speed increase at each speed level when you turn the blower speed toward HI and then decrease as you move the switch towards LO?

--

Go to Step 4

Go to Step 5

3

Turn the blower speed from OFF to LO, from Lo to MED-LO, from MED-LO to MED-HI, from MED-HI to HI and then back to OFF.

Does the blower motor speed increase at each speed level when you turn the blower speed toward HI and then decrease as you move the switch towards LO?

--

Go to Step 6

Go to Step 5

4
  1. Inspect the temperature control cable and linkages.
  2. Adjust the temperature control cable. Refer to Temperature Control Cable Replacement .

Is the action complete?

--

Go to Step 7

--

5

Refer to Heater Blower Controls System Check .

Is the action complete?

--

Go to Step 7

--

6
  1. Inspect the mode control cable and the linkages.
  2. Adjust the mode control cable. Refer to Mode Control Cable Replacement .

Is the action complete?

--

Go to Step 7

--

7

Perform the functional test. Refer to Function Test .

Is the action complete?

--

System OK

--

Heat Excessive Vent Mode

Step

Action

Value(s)

Yes

No

1
  1. Turn the ignition switch to LOCK.
  2. Move the temperature control to full HOT.
  3. Rapidly move the temperature control from HOT to full COLD.

Did you hear the temperature door slam at each end of the door's travel?

--

Go to Step 2

Go to Step 3

2
  1. Set the mode to VENT.
  2. Set the temperature control to full COLD.
  3. Start and warm-up the engine.
  4. Verify the air temperature at the blower inlet with a thermometer.
  5. Verify the air temperature at the vent outlet with a thermometer.

Is the temperature difference greater than the specified value?

5°C (9°F)

Go to Step 4

Go to Heater Blower Controls System Check

3
  1. Inspect the temperature control cable and linkages.
  2. Adjust the temperature control cable. Refer to Temperature Control Cable Replacement .

Is the action complete?

--

Go to Step 5

--

4

Inspect for hot air leaks from the engine compartment to blower air inlet. Repair as necessary.

Is the action complete?

--

Go to Step 5

--

5

Perform the functional test. Refer to Function Test .

Is the action complete?

--

System OK

--