(1) I have a 79 Bronco, 400, factory heat/ac. Heat works good at the lower vent setting and at the bi-level vents. When I change it over to the defrost position no heat comes out at the top of the dash. What can cause this. Which vacuum motor activates the defrost?

(2) At the heater/ac controls where it has the setting for cool or warm, the rod that controls the temp in the heat/ac box has been removed. How do I go about getting it apart to install one?

(3) In the heater hose lines there is what I belive is called heater water shut-off control valve. Can this be removed? My 79 truck does not have this and the heat works great.

It wont be much longer before it will be cool weather where I live so I guess I need to start working on the Bronco again soon and get it ready for winter or it is going to be a very cold ride.

 

I will try my best to give you a hand... I had some issues with my 1st 79, and was able to fix all of them...

Question 1. The controls get vaccum from the motor actually. on the back side of the engine, there is a vaccum tree. one of the lines goes threw the firewall, and to the controls. Sounds like something may be jammed or blocking the linkage from moving completely.

Question 2. Not quite sure about this one...

Question 3. I don't see why this is needed. My dad's 79 F150 had one, and we removed it with no problems. It just cuts off the hot water flow to the heater core, when the heat is off, or the A/C is on... Myself, I would just bypass it...

Hope I could help...

 

79 defroster, temp controls, heater hoses
<HR style="COLOR: #d1d1e1" SIZE=1 itxtvisited="1"><!-- / icon and title --><!-- message --><TABLE width="100%" border=0 itxtvisited="1"><TBODY itxtvisited="1"><TR itxtvisited="1"><TD vAlign=top itxtvisited="1">(1) I have a 79 Bronco, 400, factory heat/ac. Heat works good at the lower vent setting and at the bi-level vents. When I change it over to the defrost position no heat comes out at the top of the dash. What can cause this. Which vacuum motor activates the defrost? madmader has a valid thought there could be something resticting movement? the system does get vacuum from the engine. the selector lever in the dash sends the vacuum to the right dashpot to open or close the corresponding door that routes heated or cooled air to its destination. check the heater junction box, behind the ashtray. there should be a few of those dashpot visible. make sure the hose that go to them are connected and the correct ones. hope I didn't lose you on this.

(2) At the heater/ac controls where it has the setting for cool or warm, the rod that controls the temp in the heat/ac box has been removed. How do I go about getting it apart to install one? are you referring to the lever that you would slide for heat or cool in the control panel, these are changable, I believe mine are held in place by an E-clips(aka. jesus clip) oh jesus where did it go???? if your referring to the rod that goes thru the suitcase in the engine compartment. thats a hard job. about a days worth. but can be done.

(3) In the heater hose lines there is what I belive is called heater water shut-off control valve. Can this be removed? My 79 truck does not have this and the heat works great. the heater control valve shuts off the hot water to the core, and that helps the A/C get colder, so does the diverter flap you may be missing. important make sure the drain on ths suitcase is open, it should have a small rubber boot on it, to help keep it clean

It wont be much longer before it will be cool weather where I live so I guess I need to start working on the Bronco again soon and get it ready for winter or it is going to be a very cold ride. Just a thought, the A/C doesn't run on '79s when the defroster is selected, so you shouldn't have any problems there. that rod that goes thru the A/C box is cable operated, it works off the top lever from the dash controls.

Good luck, RW
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(2) At the heater/ac controls where it has the setting for cool or warm, the rod that controls the temp in the heat/ac box has been removed. How do I go about getting it apart to install one? are you referring to the lever that you would slide for heat or cool in the control panel, these are changable, I believe mine are held in place by an E-clips(aka. jesus clip) oh jesus where did it go???? if your referring to the rod that goes thru the suitcase in the engine compartment. thats a hard job. about a days worth. but can be done.

The lever in the control panel and the cable is intact. The rod that goes through the "suitcase" in the engine compartment is gone. I guess I got lucky for now it seems to be on the warm side. Thanks for everybody's help.

I fixed my defrost, loose hoses and the vent had a mouse nest in it. Obviously previous owner let it set for a while.

 

not a problem. Now that I think about it, my father had the same "visitor" living in his truck up in the defroster as well, when we revived it from the dead 7 years ago. You may want to pay a visit to a junk yard, and see if you can find on. Remember, most of the heater control parts will interchange between broncos and a F150...

 

What is the procedure for removing the heater/ac box "suitcase"? I think it will be best to replace it instead of trying to get it apart to put in a new rod. I have no idea what the previous owner did to it.

 

If it has A/C, it is a royal pain in the ***. If I remember correctly, it has to come out from under the dash. If you pull it, replace the heater core while you are in there. They are only 15 to 20 bucks at Napa. Call it preventitive maintance.

 

It has factory a/c. Might have to take a trip to the auto shop and let them take care of this one. Im only 18 and going to college and its really starting to get on my nerves that I have no time to work on my Bronco

I have so many things to do to it. Have back wheel arches cut out and replaced. Driverside floor board has a patch panel screwed onto it which needs to be removed so the floor section can be cut out and replaced, for now I just sealed it up good to prevent more rust. At the top of the cab there is some rust where it meets the windshield, need to have somebody fix that, doubt I could do it. Other than that runs good drives good, all lights work and I only gave 600 dollars for it.

 

that is funny... my bronco has rust right at the windshield as well. I have a friend that ownes a bodyshop, and he said that the wildshield will have to come out to fix that.

don't sound like a bad price for it! I gave 500 for mine, but the motor was shot. you can see pics of it at Welcome to Earlmader.com - just click on my toy truck link.

 

Motor in mine is very tight, doesnt smoke any at start up, holds good oil pressure. Awesome low end torque. Bought it with brand new 33x12.50 MT tires which cost 600 dollars. So really all I did was buy a set of tires. Ill try to get pics.

 

 

(1) D5TZ19B888A .. A/C Vacuum Damper Door Switch Assy. (Motorcraft YH13). This is the most likely cause for the problems you're having.

This switch also has the "kicker switch" on it that activates the A/C compressor when the slide is moved to A/C.

This switch is where all the vacuum lines connect, and mounts to the backside of the A/C heater control panel.

Still available from Ford.

MSRP: $168.42 / FTEpartsguy.com price: $101.05

This switch was also used on 1975/79 F100/350's with factory A/C.
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2) If I understand you correctly, this "rod' attaches to the A/C heater control panel.

If so, everything connected to this heater control panel excepting the ***** and switches was only available as an assembly.

D8TZ19980G .. A/C Heater Control Panel / Obsolete / No Ford dealer or obsolete parts seller has one. NOTE: Parts catalog sez this fits 1979 only.

The panel used in 1978 was later replaced by this one as a service part replacement. Some of the parts that originally fit 1978's are different than 1979's.
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3) D4AZ18495A .. Heater Water Control Valve (Motorcraft YG136). This valve was only used when A/C is present and is controlled by vacuum.

It's also a POS that leaks like a SOB after only a few years.

Still available from Ford, and why not? It's been a best seller since day one!

MSRP: $25.64 / FTEpartsguy.com price: $15.38.

Original Ford Parts Catalog: The 1973/79 PASSENGER Car Parts Catalog is available on a CD from hipoparts.com.

BRONCO PARTS are in the car parts catalogs 1966/79. They are in the truck parts catalogs beginning in 1980.