Heater temperature fluctuates depending on.

ANONYMOUS

MEMBER
1996 HONDA CIVIC
11,000 MILES

Heater temperature fluctuates depending on outside temperature.

As the heater control dial got stuck half way between hot and cold assumed was the problem so replaced the whole heater control unit.

Switch to fan - only working on speeds 3 & 4.

Same problem - cool air (it's around 10c outside)

Garage also replaced thermostat.

All hoses and pipes checked and not perished.

Mechanic said he had tied the temperature across to hot - but it hasn't made a difference.

Where to now?

1 Reply

KHLOW2008

MECHANIC
41,814 POSTS

Fan resistor is bad resulting in fan speed working only 3rd and highest speed.

AIR MIX CABLE
NOTE:
The purpose for adjusting the air mix cable is to ensure that the air mix door is fully closed when the maximum cool position is selected.

1. At air mix door linkage (bottom of heater case), disengage air mix cable housing from clamp. Disconnect cable wire from air mix door control arm. At heater control panel, select maximum cool position and hold it in this position.

2. At air mix door linkage, hold door control arm in maximum cool position (hold it against stop). Reconnect cable wire to door control arm. Gently slide cable housing back to eliminate slack, then snap cable housing into clamp. Adjust heater valve cable.

HEATER (COOLANT) VALVE CABLE

NOTE:Before performing this procedure, adjust the air mix cable. The purpose for adjusting the heater valve cable is to ensure that the heater valve is fully closed when the maximum cool position is selected.

1. At heater valve near engine compartment firewall, disengage cable housing from clamp and disconnect cable wire from heater valve. At control panel, set temperature control to maximum cool position and hold it in this position.

2. At air mix door linkage (bottom of heater case), hold door control arm in maximum cool position (hold it against stop). At engine compartment firewall, reconnect cable wire to heater valve. Gently slide cable housing back to eliminate slack, then snap cable housing into clamp.