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1996 bronco, 351w, E4od
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Discussion Starter · #1 ·
Hey guys,
Just installed my a/c and am getting temps of 55 with the max a/c on. I have headers and my evaporator box has no external insulation. I plan on insulating it but i was wondering if anyone had some real world data on the effectiveness of the insulation. Ex: 55 with no insulation then 40 with insulation.
 

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1987 Ford Bronco, beefed up 351w, JBG HD rear springs, JBG 4” coil, 10.25 rear posi, Dana 44 posi
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+1 on this, I also have headers and my AC has never been the best. I will measure my temp again when I get the AC recharged tomorrow. I also notice that my AC gets significantly worse at idle. Not sure if this is do to heat in engine bay or not enough airflow across condenser.
 
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1995 5.8, 2.5" Rough Country Lift, Extended RA's, 4.10's, 33" BFG's
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Mine has never had the insulation so I couldn't say for sure but I'm sure it helps, there is a fairly new thread about it in the Newbie forum.
One thing you can do is install a heater control valve, it keeps the hot water out of heater core which I know does help, I believe there is a write up on it.
You can also check your blend door to make sure its closing all the way
 
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1996 bronco, 351w, E4od
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Discussion Starter · #4 ·
Yeah i took my fluke temp gun and its 49 degrees at the top of the drier and the outside of the unprotected evaporator shroud was 170 degree. Inside the car temp with a/c on was 57. So im thinking if i can drop the box surface temp by 30 or so i should see 45-50 on the inside temps. (Also yes i did my a/c correct and no im not a pro.) i also hate on forums when people say you should have a pro do something. Thats just wack.😂
 

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Hey guys,
Just installed my a/c and am getting temps of 55 with the max a/c on. I have headers and my evaporator box has no external insulation. I plan on insulating it but i was wondering if anyone had some real world data on the effectiveness of the insulation. Ex: 55 with no insulation then 40 with insulation.
Are you sure it’s setup correctly also? Fully charged and correct pressures? My ac basically burns my hand from frostbite


Sent from my iPhone using Tapatalk
 

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1996 bronco, 351w, E4od
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Discussion Starter · #6 ·
Are you sure it’s setup correctly also? Fully charged and correct pressures? My ac basically burns my hand from frostbite


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Yes its at the correct pressures for the temperature today which was 90. Im going to replace the insulation that is missing on my evap box but idk what i should replace it with.
 

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If it is not a Bronco, it's just not worth driving.....
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+1 on this, I also have headers and my AC has never been the best. I will measure my temp again when I get the AC recharged tomorrow. I also notice that my AC gets significantly worse at idle. Not sure if this is do to heat in engine bay or not enough airflow across condenser.
Airflow across the condenser. I had the same issue with my truck and ended up putting an electric fan setup to ensure better airflow across the condenser. I now get 40 degree air out of my AC at idle ...
 

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1996 bronco, 351w, E4od
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Discussion Starter · #8 ·
Has anyone replaced the evaporator insulation and seen an a/c temp difference? Like they didnt have it and then put some custom insulation on and seen lower temps?
 

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'92 Ford Bronco XLT
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I've insualted my evap box..granted my A/C system not in tip-top shape, compressor and the condenser probably needs to be replaced but there aren't any leaks..the best it would do was 65 degrees from the register at idle with the A/C set to max..it was about 108 degrees outside at the time..

180586


180587

180585
 

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1996 bronco, 351w, E4od
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Discussion Starter · #10 ·
I've insualted my evap box..granted my A/C system not in tip-top shape, compressor and the condenser probably needs to be replaced but there aren't any leaks..the best it would do was 65 degrees from the register at idle with the A/C set to max..it was about 108 degrees outside at the time..

View attachment 180586

View attachment 180587
View attachment 180585
Thanks thats technically in spec according to someone i read on the internet who claimed to be an a/c tech. Stated that 40 degrees below ambient temps is the best you can hope for.
 

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Discussion Starter · #11 ·
OK SO update. I need something else😂 so im going to i sulate that box but i now need to know where that white vacuum like that actuates the blend door runs to because i moved it back and forth and the damn thing opens and closes. So im going to replace it but i dont know where that vacuum line runs.
 

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OK SO update. I need something else😂 so im going to i sulate that box but i now need to know where that white vacuum like that actuates the blend door runs to because i moved it back and forth and the damn thing opens and closes. So im going to replace it but i dont know where that vacuum line runs.
Yo HoustonBronco,
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 (BANNED)

Section 12-03A: Air Conditioning System, Manual A/C-Heater
1996 F-150, F-250, F-350, F-Super Duty and Bronco, F-Super Duty Motorhome Chassis Workshop Manual​
DESCRIPTION AND OPERATION
Climate Control Assembly
The A/C control (19980) is installed in the center of the instrument panel (04320).

It includes the control assembly with one knob-operated A/C temperature cable (19988) for selecting temperature. A second knob moves a selector valve that activates the various function doors and air conditioner electrical contacts. A third knob moves electrical switch contacts so that they establish continuity for one of four available positions between LOW and HIGH speed of the blower.

Air can be distributed through the instrument panel registers, the heater outlet floor ducts (18C433), and the windshield defroster hose nozzles (18490) depending upon the position of the function selector knob. Airflow to the side window demisters occurs in all knob settings.
The following chart and illustration show the vacuum system and how it controls the three airflow doors:
  • Floor/defrost (also called Defrost Door)
  • Panel/defrost (also called Panel Door)
  • Outside/recirc. (also called Recirc. Door)
FUNCTION SELECTOR SWITCH DETENT POSITIONS
Port​
Function​
Max A/C​
Norm A/C​
Vent​
Off​
Floor​
Mix​
Def.​
1 (White)​
Recirc. — O/S Air​
V​
A​
A​
V​
A​
A​
A​
2 (Red)​
Full Floor​
V​
V​
V​
V​
V​
A​
A​
3 (Yellow)​
Panel​
V​
V​
V​
V​
V​
V​
A​
4 (Blue)​
Mix​
V​
V​
V​
A​
A​
A​
A​
5 (Black)​
Source​
V​
V​
V​
V​
V​
V​
V​
V = Vacuum
A = Atmosphere

Vacuum System Diagram
180619


ItemPart NumberDescription
119A566A/C Vacuum Reservoir Tank and Bracket
219A563A/C Vacuum Check Valve
3Outside-Recirculation Door (White) (Part of Vacuum Harness)
418476Heater Core
5Vacuum Harness Connector (Part of Vacuum Harness)
619980A/C Control
7Panel Door (Blue) (Part of Vacuum Harness)
8Floor Defrost Door (Part of 18471)
9Temperature Blend Door (Part of 18471)

Airflow Control
When the function selector knob (18519) is in the A/C (MAX and NORM) and VENT positions, air flows out of the panel registers. Moving the function knob to the FLOOR position directs airflow to the heater outlet floor ducts with a slight bleed to the windshield defroster hose nozzles. The MIX position splits the air between the heater outlet floor ducts and the windshield defroster hose nozzles, and DEFROST position directs airflow to the windshield defroster hose nozzles with a slight bleed to the heater outlet floor ducts.

Airflow Through Duct System
180620

ItemPart NumberDescription
119E726A/C Instrument Panel Duct and Support
204320Instrument Panel
318C433Heater Outlet Floor Duct
4Instrument Panel Ducts (Part of 19E726)

The function knob actuates a vacuum selector valve that controls the movement of the door.
In the NORM A/C, VENT, FLOOR, MIX and DEFROST positions, outside air is drawn into the system by the blower motor (18527). In the OFF and MAX A/C positions, the recirculation door is positioned so that outside air cannot pass into the A/C evaporator case (19897). In the case of MAX A/C, passenger compartment air is recirculated. In OFF position, blower motor does not operate.

Temperature Control
Temperature is controlled by a manually operated air blend door in the heater air plenum chamber (18471). When the temperature control knob is in the extreme COOL position (fully counterclockwise) all air bypasses the heater core (18476).
When the temperature control knob is moved to the extreme WARM (fully clockwise) position, all air is directed through the heater core. When the temperature control knob is between COOL and WARM (between full counterclockwise and clockwise), air is directed through and bypassing the heater core in rough proportion to the position of the temperature control knob between the extremes of its travel.

Blower Motor Control
Speed is controlled by a four-position heater blower motor switch (18578) and a heater blower motor switch resistor (18591) located in the A/C evaporator case upstream from the A/C evaporator core (19860).
The switch is used to select LOW, two intermediate, and HIGH speed settings. The heater blower motor switch is turned off by rotating the function selector knob to its OFF position.

A/C Switch
The air conditioning system is turned on and off by the function selector switch. When the function selector knob is positioned in any A/C mode (MAX or NORM), and the engine is running, electrical current flows through the A/C cycling switch (19E561) to the A/C clutch field coil (2987), the A/C clutch (2884) engages and the air conditioning system operates (providing ambient air temperatures are above a prescribed temperature). When the function selector knob is set in the DEFROST or MIX positions and the same above conditions are met, the A/C system will also operate. This allows the operator to select the proper air temperature (when the temperature control is adjusted) for defogging the windshield and side glass when necessary, by taking advantage of the dehumidification benefits of the air conditioning system. When the function selector is placed in any other position, current is stopped to the air conditioning circuit and the A/C compressor (19703) ceases operation. ●
Outside Air Recirculation Door Hose Leak in 92-96 by John D @ How I fixed my A/C Vac Leak
 

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1996 bronco, 351w, E4od
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207 Posts
Discussion Starter · #14 ·
Yo HoustonBronco,
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 (BANNED)

Section 12-03A: Air Conditioning System, Manual A/C-Heater
1996 F-150, F-250, F-350, F-Super Duty and Bronco, F-Super Duty Motorhome Chassis Workshop Manual​
DESCRIPTION AND OPERATION
Climate Control Assembly
The A/C control (19980) is installed in the center of the instrument panel (04320).

It includes the control assembly with one knob-operated A/C temperature cable (19988) for selecting temperature. A second knob moves a selector valve that activates the various function doors and air conditioner electrical contacts. A third knob moves electrical switch contacts so that they establish continuity for one of four available positions between LOW and HIGH speed of the blower.

Air can be distributed through the instrument panel registers, the heater outlet floor ducts (18C433), and the windshield defroster hose nozzles (18490) depending upon the position of the function selector knob. Airflow to the side window demisters occurs in all knob settings.
The following chart and illustration show the vacuum system and how it controls the three airflow doors:
  • Floor/defrost (also called Defrost Door)
  • Panel/defrost (also called Panel Door)
  • Outside/recirc. (also called Recirc. Door)
FUNCTION SELECTOR SWITCH DETENT POSITIONS
Port​
Function​
Max A/C​
Norm A/C​
Vent​
Off​
Floor​
Mix​
Def.​
1 (White)​
Recirc. — O/S Air​
V​
A​
A​
V​
A​
A​
A​
2 (Red)​
Full Floor​
V​
V​
V​
V​
V​
A​
A​
3 (Yellow)​
Panel​
V​
V​
V​
V​
V​
V​
A​
4 (Blue)​
Mix​
V​
V​
V​
A​
A​
A​
A​
5 (Black)​
Source​
V​
V​
V​
V​
V​
V​
V​
V = Vacuum
A = Atmosphere

Vacuum System Diagram
View attachment 180619

ItemPart NumberDescription
119A566A/C Vacuum Reservoir Tank and Bracket
219A563A/C Vacuum Check Valve
3Outside-Recirculation Door (White) (Part of Vacuum Harness)
418476Heater Core
5Vacuum Harness Connector (Part of Vacuum Harness)
619980A/C Control
7Panel Door (Blue) (Part of Vacuum Harness)
8Floor Defrost Door (Part of 18471)
9Temperature Blend Door (Part of 18471)

Airflow Control
When the function selector knob (18519) is in the A/C (MAX and NORM) and VENT positions, air flows out of the panel registers. Moving the function knob to the FLOOR position directs airflow to the heater outlet floor ducts with a slight bleed to the windshield defroster hose nozzles. The MIX position splits the air between the heater outlet floor ducts and the windshield defroster hose nozzles, and DEFROST position directs airflow to the windshield defroster hose nozzles with a slight bleed to the heater outlet floor ducts.

Airflow Through Duct System
View attachment 180620
ItemPart NumberDescription
119E726A/C Instrument Panel Duct and Support
204320Instrument Panel
318C433Heater Outlet Floor Duct
4Instrument Panel Ducts (Part of 19E726)

The function knob actuates a vacuum selector valve that controls the movement of the door.
In the NORM A/C, VENT, FLOOR, MIX and DEFROST positions, outside air is drawn into the system by the blower motor (18527). In the OFF and MAX A/C positions, the recirculation door is positioned so that outside air cannot pass into the A/C evaporator case (19897). In the case of MAX A/C, passenger compartment air is recirculated. In OFF position, blower motor does not operate.

Temperature Control
Temperature is controlled by a manually operated air blend door in the heater air plenum chamber (18471). When the temperature control knob is in the extreme COOL position (fully counterclockwise) all air bypasses the heater core (18476).
When the temperature control knob is moved to the extreme WARM (fully clockwise) position, all air is directed through the heater core. When the temperature control knob is between COOL and WARM (between full counterclockwise and clockwise), air is directed through and bypassing the heater core in rough proportion to the position of the temperature control knob between the extremes of its travel.

Blower Motor Control
Speed is controlled by a four-position heater blower motor switch (18578) and a heater blower motor switch resistor (18591) located in the A/C evaporator case upstream from the A/C evaporator core (19860).
The switch is used to select LOW, two intermediate, and HIGH speed settings. The heater blower motor switch is turned off by rotating the function selector knob to its OFF position.

A/C Switch
The air conditioning system is turned on and off by the function selector switch. When the function selector knob is positioned in any A/C mode (MAX or NORM), and the engine is running, electrical current flows through the A/C cycling switch (19E561) to the A/C clutch field coil (2987), the A/C clutch (2884) engages and the air conditioning system operates (providing ambient air temperatures are above a prescribed temperature). When the function selector knob is set in the DEFROST or MIX positions and the same above conditions are met, the A/C system will also operate. This allows the operator to select the proper air temperature (when the temperature control is adjusted) for defogging the windshield and side glass when necessary, by taking advantage of the dehumidification benefits of the air conditioning system. When the function selector is placed in any other position, current is stopped to the air conditioning circuit and the A/C compressor (19703) ceases operation. ●
Outside Air Recirculation Door Hose Leak in 92-96 by John D @ How I fixed my A/C Vac Leak
Thanks i got it fixed my vacuum line was shit and leaking so i fixed it and its at 48-50 now. Which is the same as a new 2021 f250 so im good with that. If i wanted more cooling ill go grab some forbidden r12 i have laying around.😂 you know just redo the whole thing
 

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Discussion Starter · #17 ·
Excellent. I would clean the coil and radiator behind it just to say you did unless its the door in the evap/fan housing that Miesk5 mentioned. I have seen both issues cause the same thing.
Coil? Im not understanding what coil your referring to. My whole a/c is new minus the evaporator which looked super clean and freshly replaced when i replaced my fan motor.
 

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Discussion Starter · #19 ·
Condenser coil. But it looks like it was the door so grats on getting it corrected.
Yes thanks the vacuum line ended up being cracked in the loom tubing. The line held vacuum a but it was staying as closed as it should be.
 

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I insulated my box like jermil01 showed in his post. I used Thermo-Tec 13590, it covered the box easily and it made a significant difference in the AC performance. I'm running headers so it made sense to cover the box while I was working in the engine bay. When you get the opportunity, insulate.

Box opened up for new condenser.
180753


Condenser installed.
180754


Covered with Thermo-Tec.
180755
 
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