c17r15

hey all,
It's getting into the 30's here in GA and I can't seem to get heat.

The heater valve cable is not doing anything when I turn the tempurature knob, so it's either the knob or the motor.

1. How much is a heater valve motor?
2. Can I manually turn the valve?

thanks!
chris

Slows2k

1. don't know
2. take the cable off the heater valve under the hood and move the lever.

xviper

The heater valve is not motorized. It's a cable actuated valve. The cable has most likely come loose or the valve lever movement is being impeded by something.

c17r15

the cable is tight and the lever is clear of obstacles.

I had my friend turn the knob and the lever doesn't do ANYTHING.

the valve is cable actuated, but the cable is pulled by a motor, no?

xviper

No, the cable is directly attached to the heater knob inside the car. If you move the knob, do you see the cable move at the valve? If not then the cable has come loose from behind the knob. If you see the cable move at the valve by the battery but the valve lever doesn't move, then the cable has come loose at that point.

Slows2k

The cable is moved by the air mix control motor. Just because it doesn't move doesn't mean the motor is bad. The heater control panel could also be faulty.

The heater control panel does have a self diagnosis function, which is documented in the Helm manual.

fuse #20, and 25 in the under dash fuse box are both for the heater panel. Check those 1st.

c17r15

okay this is strange.

last night I unlatched the cable and manually opened the valve but there's still no heat. both hoses, going in and coming out of the heater core, are hot but the air is blowing cold.

my AC and fan both works but that's worthless to me in this cold weather.

I ran the self-diagnostic and it was blinking once every second and does not stop, i'm guessing this means it's code 1, air mix control motor circuit.

any ideas? I've bypassed air mix control motor circuit...i think.

does the air mix control motor pull the cable AND open up the passage way between the heater core and the blower/evaporator unit?

xviper

As usual, Slow is right about the connection between the "heat" knob and the coolant inlet valve. The knob is linked electronically to the air mix motor and it's from a lever assembly on this motor that a cable goes to the valve. That motor also controls the "doors" and valves inside the cabin airbox.

Intrepid175

Heat output in most modern cars is controlled by more than just opening and closing a valve that let's hot water in from the engine. The ventilation system on the car has air being drawn in from outside. It then passes through the A/C evaporator. If the heater control knob on the dash is to full cold, the air is then discharged through whatever vents are selected from the control panel, ie the dash, floor, defrost, or any combination thereof.

If the heater control valve is not at full cold, then a blend air door, which sits between the A/C evaporator and the heater core, will open to route some or all of the air through the heater core before it is discharged into the cabin. The amount of air routed depends on how far the control knob is rotated which controls how far the blend air door opens.

I "think" the servo that controls the blend air door is electric but it may be vacuum operated. Either way, you need to make sure it's working properly. It makes no difference if the heat valve in the engine compartment is working or not. If the system isn't routing air through the heater core in the dash, you're not going to get hot air.

Good luck & let us know how it goes!

Drive Safe,
Steve R.

Slows2k

The HVAC controls are all electric, no vaccum operation here.

The air mix control motor moves the H20 valve undr the hood, and the air mix door in the heater box. If the air mix door is clsed, you get no heat.

I have no idea how you may of bypassed the air mix circuit. The air mix motor need to be removed to check bench test it's operation. Your problem could be in 3 places. The air mix motor, the control panel, or the wiring in between.