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FORD BRONCO -> CLIMATE CONTROL; heater, AC, blower motor/resistor -> Doors & Vacuum Motors: Outside Recirculate, Panel, Floor/Defrost; & Temperature Blend Door that is Cable Controlled (controls temperature)core & Defrost Door)
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Engine Coolant Concerns TSB 93-24-08 for 84-94 Bronco, F Series, Aerostar, Econoline & many others
Lack of Heat, Temperature Blend Door Cam Spring Does Not Blend Door to Seat Properly TSB 92-4-13 for Vehicles Built Prior to 11/11/91, 92 Bronco & F Series & F-47
Revised Temperature Blend Door Cable TSB 95-11-10 for 95 Bronco & F Series
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Cable Operation; "...ALL of our trucks have vacuum motors for the distribution doors exactly like Rob's diagram, EXCEPT 87-early 88 (and mine because I swapped that style in). Only those 2 years used a cable going to a compound lever for the distribution doors. ALL use vacuum for the recirc motor & ALL use cable for the temperature blend door..."
Source: by Steve83 (Steve, That dirty old truck) at FSB
Overview in 80-86; "Off - Vacuum is applied to da Outside Recirc Door Vac Motor, closing that door to outside Air. Normal A/C - Outside-Recirc Door is open to outside air. The panel door directs air to the instr panel registers. The Temperature Control Lever moves a cable connected to da Temp Blend Door that mixes heated & un-heated air. In Defrost Mode - No vacuum to any vacuum "motor" (cannisters looking thangs), air Flows to Defroster outlets (& air compr clutch is engergized). Vent - Outside Recirc Door is open to outside air, as in Normal A/C. Vacuum is applied to the Panel Door Vacuum Motor, letting air flow only to the instr panel registers. In the same way, the defroster outlets are closed by the Floor/Defrost Vacuum Motor. Floor - The Outside-Recirc Door is Open to outside air. With No Vacuum at the Panel Door Vacuum Motor. The Panel Door directs air to the floor outlets. Mix - Vacuum is applied only to Port A of the Floor/Defrost Vacuum Motor positioning the Floor/Defrost Door at mid-position. Air Flow is split between the floor & windshield. There is no vac at the Panel Door Vacuum"
Source: by miesk5 at FSB
"...If all the controls are functioning and you can actually see the cable moving the actuator lever, and you still can't get warm air then most likely your problem is going to be the blend temp door inside the HAVC box. The door is hinged by a piece of flexible plastic, the hinge wears out and breaks then it is not forced into the hot air position by the cable. I found a good one in the junk yard and replaced mine. You have to take most of the dash apart to get to the thing. It takes a while to complete this repair..."
Source: by JDApollo (John A) at FSB
"...Some of the later control panels with knobs have mostly cables behind them, and others use more vacuum. If you get a vacuum leak, you'll lose control, just like if a cable pops loose. It's pretty easy to pull the panel out a little & inspect behind it; & If you can pull your radio out, you can look at the top of the A/C controls. Sometimes a wire from the radio gets tangled in the mechanism, and it can lock it. Or, the cables that connect the slides to the blend doors can kink or come loose. It's most common for the cable to pop out AT the blend door lever, over the passenger footwell, but that never locks the control, so it's probably not what happened in yours...."
Source: by Steve83 (Steve, That dirty old truck) at FSB
"...The air handling system is designed to provide defrost when no vacuum is applied to any of the three air door vacuum motors. This is done to prevent a situation where defrost cannot be obtained due to a system vacuum leak. Instead, a leak in the vacuum control circuit will send all airflow to the defroster outlets. This condition may occur during acceleration (slow leak), may exist at all times (large leak) and may happen only when certain specific functions are selected, indicating a leak in that portion of the circuit. ..." from F-150, F-250, F-350, F-Super Duty and Bronco, F-Super Duty Motorhome Chassis Workshop Manual
Source: by Ford via thedieselstop.com
"...The later trucks got pivots instead of the film hinges our older trucks were built with..."
Source: by Steve83 (Steve, That dirty old truck) at FSB
Air Conditioning & Heater Vacuum Diagram in a 95
Source: by Chilton
Blend Door Control Cable Location pic for 92-96 Bronco & F Series
Source: by Steve83 (Steve, That dirty old truck) at SuperMotors.net
Blend Door Control Cable Location, Behind Control Panel Diagram in a 78
Source: by Indybronco (Lula Mae) at SuperMotors.net
Blend Door Control Cable pic in a 92
Source: by 2bet at SuperMotors.net
Blend Door Location & Replacement Info in an 83; "...If you can take out your glove box, it will make it much easier. If not, you can probably feel around and find it. Just above the box housing the heater core you should find a clamp that holds the other end of the cable from your heater controls. Follow that about an inch or three towards the driver's side until you feel a lever. This controls the little door that bypasses the heater. Just move that lever/door and you should be running heat...."
Source: by darb at FSB
Blend Door Location in a 94; 80-96 similar; "...Probably the temp blend door is loose & flopping around on its own. The easiest way to see it is to fully lower the glove box, pull the ~8 screws from the heater core cover, & look inside to the L (driver's side). You'll see the cable & control lever (in top L of 2nd pic) as soon as you fold the glovebox down, so inspect it first. The 3rd shows the whole cover - it's the large section in the top center with tiny white numbers inked near its bottom edge. The cables are visible, too...."
Source: by Steve83 (Steve, That dirty old truck) at FSB
Blend Door Repair, Ranger, Explorer, Expedition
Source: by jfranks via blenddoorfix.netfirms.com
Blend Door Repair, Ranger, Explorer, Expedition
Source: by jfranks at earthlink.net
Blend Door Replacement in 80-86; "...the air coming thru the heater core was hot. Now you're saying it's cooler by the time it makes it to the dash registers??? The only way for that to happen is for it to mix with cooler air in between. The most likely spot is at the temperature blend door (shown in that diagram). If it doesn't FULLY close off the cold side, you'd feel hot air if you remove the cover behind the glove box, but it would be cooler at whatever register you select (floor, dash, defrost). You have to pull either the heater core or the evaporator core to see the blend door. Obviously, the heater core is easier, but you don't have to open the A/C system to pull the evap. out..."
Source: by Steve83 (Steve, That dirty old truck) at FSB
Door Locations Diagram & Overview in an 86; Floor/Defrost, Panel, Temperature Blend (cable controlled), Outside Recirculate Air; in Electrical and Vacuum Troubleshooting Manual (EVTM) Partial, Bronco for 86; see Pages 141, 142 & 143
Source: by Chris B (Blue, bronco boy) at telus.net
Door Locations in Parts Break-Out Diagram in 80-86; temperature blend door, vacuum motors, heater core, upper & lower plenum depictions, etc.
Source: by Steve83 (Steve, That dirty old truck) at SuperMotors.net
Door Locations in Parts Break-Out Diagram in 80-86; temperature blend door, vacuum motors, heater core, upper & lower plenum depictions, etc.
Source: by HawkRdr at SuperMotors.net
Door Locations pic in 80-86 w/Dash dropped; "...After lowering the column, removing the big Aluminum casting, unbolting the 2 large connectors under the brake booster & releasing them from the firewall, the 3 connectors in the R kick, & the green ground screw, there are four 7mm (T15) screws along the w/s, an 8mm (5/16") at the R end, and two 8mm screws at the brace bars above the tunnel, and the dash flops onto the floor. Then the vacuum lines, HVAC cables, & antenna cable can be released, allowing the dash to come out..."
Source: by Steve83 (Steve, That dirty old truck) at SuperMotors.net
Electronic Automatic Temperature Control (EATC) Conversion in a Crown Vic, but Possible for Broncos & F Series
Source: by 2vmodular at p71interceptor.com
Engine Coolant Concerns TSB 93-24-08 for 84-94 Bronco, F Series, Aerostar, Econoline & many others; See table for checking any binding in Mode and Blend doors; "...ISSUE: Engine performance concerns such as hesitation or stall, rough idle, and/or poor fuel economy may be caused by the thermostat stuck in an open position or opening at a temperature lower than specified. ACTION: Use the following "Cooling System Diagnosis" procedure to diagnose a cooling system that may not be reaching normal operating temperature. Follow the "Thermostat Diagnosis" procedure to determine if the thermostat may be at fault. Check the thermostat without removing it from the vehicle by using Rotunda Service Coolant Temperature Monitor Harness 007-00064. DIAGNOSIS PROCEDURE; A new cooling system diagnosis procedure has been developed for engines that do not reach normal operating temperature. A new thermostat diagnosis procedure also has been developed, using a new service coolant temperature monitor harness. See chart for proper diagnostic procedure. NOTE: THIS PROCEDURE WILL DIAGNOSE ONLY COOLING SYSTEMS THAT MAY NOT BE REACHING NORMAL OPERATING TEMPERATURE. IT WILL NOT DIAGNOSE A THERMOSTAT THAT CAUSES AN ENGINE OVERHEAT CONDITION. THERMOSTAT DIAGNOSIS; NOTE: DISCONNECTING THE POWERTRAIN CONTROL MODULE (PCM) TO ATTACH A BREAKOUT BOX OR AN EEC IV MONITOR WILL ERASE THE ADAPTIVE LEARNING FROM MEMORY AND MAY "HIDE" A DRIVE CONCERN TEMPORARILY UNTIL THE ADAPTIVE LEARNING IS RE-LEARNED. NOTE: THIS PROCEDURE IS MOST ACCURATE IF PERFORMED INDOORS AT LESS THAN 100°F (38°C) AMBIENT TEMPERATURE. THIS TEST MAY BE PERFORMED WITH OR WITHOUT THE HOOD OPEN AND WITH THE ENGINE WARM OR COLD. CAUTION: ALWAYS VENT THE EXHAUST TO THE OUTSIDE WHEN PERFORMING THIS TEST. 1. Check the coolant level in the radiator and coolant recovery reservoir. 2. With the key in the "off" position, proceed as follows: a. Remove the engine coolant temperature (ECT) sensor harness connector. b. Attach Rotunda Service Coolant Temperature Monitor Harness 007-00064 as a jumper between the PCM and the ECT. c. Attach Rotunda 73 Digital Multimeter 105-00051 or equivalent to the thermostat monitor harness. Voltage values (0-5vdc) may now be monitored while the sensor retains its connection to the wiring harness. NOTE: A ROTUNDA NEW GENERATION STAR TESTER (NGS) 007-00500 OR THE ROTUNDA SERVICE BAY DIAGNOSTIC SYSTEM (SBDS) 001-00001 MAY BE USED TO MONITOR THE ECT ON VEHICLES EQUIPPED WITH DATA COMMUNICATIONS LINK (DCL). THE SBDS SEQUENCE TO USE FOR THE SCREEN IS "TOOLBOX - ELECTRONIC ENGINE CONTROL AND DCL - ITEM". 3. Vehicles equipped with electric engine cooling fan(s) must have a fan running during this test (high or low speed may be used). Two methods may be used to turn the fan(s) on: a. Disconnect the A/C compressor clutch power supply and turn the climate control to A/C "ON". Or b. Disconnect the power supply to the cooling fan and supply 12 volts direct to the fan connector from the battery. NOTE: A GROUND MAY BE REQUIRED FOR SOME APPLICATIONS. 4. Place transmission in "park" or "neutral". NOTE: RUNNING THIS TEST WITH THE VEHICLE IN GEAR OR WITH THE A/C COMPRESSOR CLUTCH ENGAGED (RUNNING) WILL CAUSE IMPROPER DIAGNOSIS 5. Start the engine and allow to idle throughout this test: a. Allow engine to run for 2 minutes, then record ECT voltage. b. From now on, record ECT voltage every 60 seconds. c. When the ECT voltage trend changes direction or changes only slightly (0.03 volts or less) from the previous reading, record this as the thermostat opening voltage. d. Use the "Voltage and Corresponding Temperature Chart" shown below to obtain actual coolant temperatures. 6. If the opening voltage is GREATER than 0.75 volts (less than 180° F/ 82° C), or 0.85 volts (170° F/ 77° C) for 2.3L HSC engine only, replace the thermostat. Refer to the dealer Master Parts Catalog for correct thermostat usage. 7. If the thermostat opening voltage is LESS than 0.75 volts (greater than 180° F/ 82° C), or 0.85 volts (170° F/ 77° C) for 2.3L HSC engine only, the thermostat is good and should NOT be replaced. The "Cooling System Diagnosis Chart" should be referenced for further instructions. NOTE: The 10° F opening temperature difference for the 2.3L HSC engine is due to the ECT sensor location. OTHER APPLICABLE ARTICLES: NONE SUPERSEDES: 93-14-04 WARRANTY STATUS: INFORMATION ONLY..."
Source: by Ford via Steve83 (Steve, That dirty old truck) at SuperMotors.net
Floor Panel Door Location & Removal in an 86; "...I think the easiest way to fix it would be to go in through the heater core (behind the glove compartment)and on the left should be the panel door. Replace the panel door ..."
Source: by rust bucket 86 at Ford Bronco Zone Forums
Floor Panel Door, Temperature Blend Door (Cable Controlled), Floor & Defrost Door etc. Location w/Vacuum Line Colors in Parts Break-Out Diagram in a 96 from Workshop Manual
Source: by Ford via thedieselstop.com
Floor Panel Door, Temperature Blend Door (Cable Controlled), Floor Defrost Door, Outside Recirculate Air Diagram in a 96 from Workshop Manual
Source: by Ford via miesk5 at Ford Bronco Zone Forums
Floor/Defrost Vacuum Motor Location Depiction in 80-86
Source: by Steve83 (Steve, That dirty old truck) at SuperMotors.net
Lack of Heat, Temperature Blend Door Cam Spring Does Not Blend Door to Seat Properly TSB 92-4-13 for Vehicles Built Prior to 11/11/91, 92 Bronco & F Series & F-47
Source: by Ford via Chilton
No Heat or Lever Doesn't Provide Enough Heat; "...i have an 88 when i pulled the radio out and i pulled the thermostat pannel out is was just as simple to pop the cable back into the litle clipy thing and then i had heat...."
Source: by killa bronco (Charlie) at FSB
No Heat/Heat in a 94; "...The diverter door (panel, defrost, floor) is totally independent of the blend door (hot/cold), and it's vacuum-operated, so it'll always be slow; Probably the temp blend door is loose & flopping around on its own. The easiest way to see it is to fully lower the glove box, pull the ~8 screws from the heater core cover, & look inside to the L (driver's side). You'll see the cable & control lever (in top L of 2nd pic) as soon as you fold the glovebox down, so inspect it first. The 3rd shows the whole cover - it's the large section in the top center with tiny white numbers inked near its bottom edge. The cables are visible, too...The diverter door (panel, defrost, floor) is totally independent of the blend door (hot/cold), and it's vacuum-operated, so it'll always be slow. Concentrate on the blend door for now. pull the cover & look at it..."
Source: by Steve83 (Steve, That dirty old truck) at FSB
Not Much or No Heat in an 86; "...You should also check the blend door to see if it's switching to hot. If you pull the glove box out, you can see the cable going to it on top of the ductwork as you move the slide. If it has NO resistance or if it binds, then the door might have broken away from its film hinge..."
Source: by Steve83 (Steve, That dirty old truck) at FSB
Parts Break-Out Diagram in a 78 w/ out Nomenclature
Source: by broncohq.com
Vacuum Circuit, Floor Panel Door, Temperature Blend Door (Cable Controlled), Floor & Defrost Door etc. Diagrams in a 96 from Workshop Manual
Source: by Ford via thedieselstop.com
Vacuum Hose Harness Pic in 80-96; "...80-96 similar, except 87-early 88 w/factory air; The 80-86 vacuum tank is a plastic ball on the R wheelwell..."
Source: by Steve83 (Steve, That dirty old truck) at SuperMotors.net
Vacuum Motor Locations in Parts Break-Out Diagram in 80-86
Source: by Steve83 (Steve, That dirty old truck) at SuperMotors.net