How can I install an A/C heater temperature control unit?

This year and model doesn't have a heater control valve it uses what is called an electrically actuated air temperature control blend door to control heated air and AC temperatures.

Hi Sharon, I'm glad to help. Your 2000 year doesn't have a motor for the temp door. It operated by a cable running from the control head to the temp door and you work it manually. If you can't control the temperature from hot to cold, sometimes the cable come off or breaks. Here how you can see the cable to see if its working. Remove the radio and right behind it you will see the cable attached to the door, while watching it move the temp lever from hot to cold and watch it. If it is moving then its most likely out of ajustment. If it is not moving, then you'll need a new cable. Just in case it is moving, I'm attaching the instruction on how to adjust it below. Hope this helps and have an awesome day Sharon!

TEMPERATURE CONTROL CABLE

Any time the heater-A/C control or the temperature control cable are removed and/or replaced, the following procedure must be performed.

1. The temperature control cable housing and core must be installed at both the heater-A/C control and the heater-A/C housing ends, and the heater-A/C control must be installed in the instrument panel. See Heater-A/C Control and Temperature Control Cable in the Removal and Installation section of this group for the procedures.
2. Rotate the temperature control knob on the heater-A/C control so that the knob pointer is in the 12 o'clock position.
3. Pull the temperature control knob straight out from the heater-A/C control base until the perimeter of the knob (not the knob pointer) protrudes about 6 millimeters (0.25 inch) from the face of the control base.
4. Rotate the temperature control knob to the 1 o'clock position. Push in on the knob slightly and continue rotating the knob to its full clockwise stop. The knob pointer should be aimed at a position about 8 millimeters (0.315 inch) beyond the end of the graduated red strobe temperature control graphic on the face of the heater-A/C control base. If the knob is not pointed to the correct position, go back to Step 2 and repeat the adjustment procedure.
5. Rotate the temperature control knob counterclockwise until the knob pointer is in the 12 o'clock position again.
6. Push the temperature control knob straight in towards the heater-A/C control base until the perimeter of the knob (not the knob pointer) is flush with the face of the heater-A/C control base.
7. Rotate the knob to its full clockwise stop again. The knob pointer should be aimed at the end of the graduated red strobe temperature control graphic on the face of the heater-A/C control base. If OK, go to Step 8. If not OK, go back to Step 2.
8. Rotate the knob to its full counterclockwise stop and release the knob. If the knob springs back from the counterclockwise stop, the self-adjuster clip that secures the temperature control cable to the blend-air door lever is improperly installed. See Temperature Control Cable in the Removal and Installation section of this group for the procedures. If the knob does not spring back, the temperature control cable adjustment is complete.

Its a faulty heater control valve that is located in between the engine and the heater core or just before the firewall.

why are you replacing it?

SECTION 412-04: Control Components 2000 Escort Workshop Manual REMOVAL AND INSTALLATION Procedure revision date: 08/04/1999
Control Assembly
Special Tool(s) Remover, Audio Unit
415-001 (T87P-19061-A)
Removal

1. Disconnect the battery ground cable (14301).

1. Rotate the temperature control switch to the COOL position.

1. Disconnect the A/C temperature cable (19988) from the heater core housing.
   1. Unlock the heater temperature cable by pulling down the tab.
   1. Disconnect the heater temperature cable while holding the tab down.

1. Use the Radio Removing Tool to pull the integrated control panel out of the instrument panel (04320).

1. Disconnect the vacuum harness from the function selector switch.

1. Disconnect the radio antenna lead in cable (18812) and the electrical connectors and remove the control assembly.

Installation

1. Follow the removal procedure in reverse order.

Volvo Cars 1999-05 - S40 And V40 Models
Heater Core - Removal & Installation

1. Before servicing the vehicle, refer to the Precautions Section.
2. In the engine compartment:
   1. Remove the top splashguard.
   2. Install two hose clips on the hoses to the heat exchanger. Remove the hoses.
   3. Remove the air conditioning pipe in the engine compartment from the support.
      
3. In the passenger compartment:
   1. Disconnect the wiring and the connectors located on the center support.
   2. Remove the mounting bolts from the center support. Remove the support.
   3. Remove the control panel.
   4. Disconnect all the connectors.
   5. Remove the power unit
4. Cars with air conditioning remove the air conditioning pipe in the engine compartment from the support.
5. Remove the bolts and the nut from the power unit. Pull the power unit backwards as far as possible
6. Remove the upper section from the housing.
7. Remove the section that connects with the floor heater.
   
   
   Fig. Heater unit-S40, V40
   

Heater unit-S40, V40

1. Press the pipes down. Remove the lower section.
2. Remove the four mounting bolts.
3. Pull off the housing. Press the floor heater down. Remove the housing.
4. Remove the control lever on the valve side.
5. Remove the mounting and the clips around it.
6. Carefully separate the components.
7. Replace damaged components if necessary.
   NOTE Do not disassemble damper motors when adjusting.
8. Replace the refrigerant temperature sensor.
9. Replace the heat exchanger.
10. Check the seals (also on the dampers).
11. Install the control mechanism last.
12. Install in reverse order.
13. Check the setting of the damper motors.

Hope this help (remember comment and rated this).

Removal

1. Disconnect the battery ground cable.
2. Drain the engine coolant.
3. Discharge and recover refrigerant (with air conditioning).
4. Remove heater unit.
5. Remove duct.
6. Remove case (Mode control) and do not remove link unit at this step.

Remove case (Temperature control) separate two halves of core case

1. Remove heater core (1).

.

1. Pull out the mode door while raising up the catch of the door lever.

Installation
To install, follow the removal steps in the reverse order, noting the following point:

1. Check that each mode door operates properly.

Sounds like the heater control unit is going bad. I believe this unit has a digital/vacuum control unit which explains why you are only getting hot out of one vent. Try the salvage yard or ebay for a replacement unit. They are non-repairable...

This is for the 1.8L and the 1.9L engine:

1.8L & 1.9L Engines CAUTION NEVER open, service or drain the radiator or cooling system when hot; serious burns can occur from the steam and hot coolant. Also, when draining engine coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantities. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

1. Disconnect the negative battery cable. If equipped, disable the SRS system.
   
2. Drain the cooling system.
   
3. Disconnect the heater hoses at the firewall.
   
4. Remove the instrument panel.
   
5. Disconnect the mode selector and temperature control cables from the cams and retaining clips.
   
1. Remove the necessary defroster duct screws and loosen the cap screw that secures the heater-to-blower clamp.
   
2. Remove the three heater unit mounting nuts and disconnect the antenna lead from the retaining clip.
   
3. Remove the heater unit.
   
4. Remove the insulator and the four brace cap screws.
   
5. Remove the brace.
   
6. Remove the heater core from the heater unit.
   
6. To install:
   
   1. Install the heater core into the heater unit.
      
   2. Install the brace.
      
   3. Install the brace cap screws and the insulator.
      
   4. Place the heater unit into position, then attach the defroster and floor ducting.
      
   5. Install the heater unit mounting nuts.
      
   6. Tighten the heater-to-blower clamp cap screw and install the defroster duct screws.
      
   7. Connect the antenna lead to the retaining clip.
      
   8. Install the instrument panel.
      
   9. Connect and adjust the mode selector and temperature control cables.
      
   10. Connect the heater hoses at the firewall.
       
   11. Fill the cooling system and connect the negative battery cable.
       
   12. Start the engine and check for leaks.
       
   13. Check the coolant level and fill as necessary.
       

You have one of two possible problems.

1) The temperature shaft retention nut is loose behind the knob

2.) The wires to the potentiometer part of the temperature may be broken.

Either one is common to this vehicle. The replacement of the AC controller is about 900 dollars. If the wires are broken, they can easily be reattached to the circuit board via soldering. What you would have to do is remove the control box from the dash, and disassemble it. Once the unit is apart, there are 3 wires from the temp knob to the circuit board that need to be re-soldered. The unit CAN be repaired, as opposed to the expense of replacing it.

1991-95 Models

1. Disable the air bag system by disconnecting the negative battery cable.
2. Have the system discharged by a qualified professional mechanic using an approved recovery/recycling machine.
3. Drain the cooling system.
4. Remove the steering column cover and left and right side under panel silencers.
5. Remove the center bezel by unclipping it from the instrument panel.
6. Remove the accessory switch carrier and the heater/air conditioning control head.
7. Remove storage bin and lower right instrument panel.
8. Disconnect the blower motor lead under the right side of the instrument panel.
9. Remove the right side 40-way connector wiring bracket.
10. Remove the lower right reinforcement, body computer bracket and mid-to-lower reinforcement as an assembly.
11. Disconnect the vacuum lines at the brake booster and water valve.
12. Clamp off the heater hoses near the heater core and remove the hoses from the core tubes. Plug the hose ends and the core tubes to prevent spillage of coolant.
13. If equipped with air conditioning, remove the H-valve and condensation tube.
14. Disconnect the temperature control cable and vacuum harness at the connection at the top of the unit.
15. Remove the retaining nuts from the package mounting studs at the firewall. Disconnect the hanger strap from the package and rotate it aside.

To install:

1. Remove the temperature control door from the unit and clean the unit out with solvent. Lubricate the lower pivot rod and its well and install. Wrap the heater core and/or evaporator with foam tape and place in position. Secure with the screws.
2. Assemble the unit, making sure all vacuum tubes are properly routed.
3. Install the assembly to the vehicle and connect the vacuum harness. Install the nuts to the firewall and install the condensation tube. Fold the carpeting back into position.
4. Connect the hanger strap from the package and rotate it aside. Install the 2 brackets supporting the lower edge of the heater housing. Connect the blower motor wiring, resistor wiring and the temperature control cable.
5. Install the retaining screws from the right side to the steering column. Install the instrument panel trim covering and reinforcement.
6. Assemble the unit, making sure all vacuum tubes are properly routed.
7. Install the assembly to the vehicle and connect the vacuum harness. Install the nuts to the firewall and install the condensation tube. Fold the carpeting back into position.
8. Connect the hanger strap from the package and rotate it aside. Connect the blower motor wiring and temperature control cable.
9. Install the lower right reinforcement, body computer bracket and mid-to-lower reinforcement as an assembly.
10. Install the right side 40-way connector wiring bracket.
11. Install the lower right instrument panel and storage bin.
12. Install the heater/air conditioning control head and accessory switch carrier.
13. Install the center bezel to the instrument panel.
14. Install the under panel silencers and steering column cover.
15. Install the vacuum lines at the brake booster and water valve.
16. Connect the heater hoses to the core tubes.
17. Using new gaskets, install the H-valve and connect the refrigerant lines. Install the condensation tube.
18. Have the system evacuated and recharged by a qualified professional mechanic, utilizing the proper equipment. Add 2 fl. oz. (59 ml) of refrigerant oil during the recharge. Fill the cooling system.
19. Perform the Air Bag System Check procedures outlined in this section before connecting the negative battery cable.
20. Connect the negative battery cable and check the entire climate control system for proper operation and leaks.