Hilton

Look in the HVAC section of Pirtle's site:

http://members.rennlist.com/pirtle/svc.html

(HVAC - Heating Ventilation Air-Conditioning)

Search terms you may find useful here are: vacuum diaphragm HVAC blows hot

Start off by getting a hand-vacuum pump with a gauge, and testing the vacuum lines at the small manifold in the centre console under the AC control unit.

You need to take both sides off the centre console, undo 3 philips screws (will need a stubby screwdriver for the middle one), and then you can pull the manifold gently out the driver's side of the console to unplug and test each coloured line to see if it holds vacuum.

If any of them leak, the whole system will blow warm.

76FJ55

The first and easiest thing to check is probably the vacuum line connection by the master cylinder. this line supplies the HVAC system with engine vacuum. if it is loose there will be no vac in the system so the heater valve will stay open and none of the vent controls will work. It is common for the is some what common for this connection to get knocked loose.

from Dwayne's post. '87 HVAC Vacuum Leak Testing and Repair Procedure w/pics

riviera455

thanks for these fantastic links, i will find a solution now, and yes it will be a vacuum problem,,my cruisecontrol wont work either. i hear a click when i activate the cruisecontrol, but it does not hold speed. i think a leaking actuator or broken or loose line somwhere that created more than one problem. all vacuum related problems.
i hope to have time this weekend to find wat is realy wrong.

Bill Ball

Dwayne's guide is fanatastic. Word of caution - In this pic from Dwayne's guide notice the red and red/black wires near the bracket. If you are reinstalling this bracket be careful not to pinch any of these wires under it. I am working on a car where the red/black wire was shorted to the bracket. This is the ignition feed to the radio.

Jim Devine

read this- it should help

https://www.928gt.com/t-wallyhvac.aspx

Hilton

One thing to add..

Check the vacuum lines from the blue check-valve by the brake booster and into the left-front fender. Behind the left-front wheel is the vacuum reservoir, and also the cruise control actuator. Make sure the connections to both are plugged in and not open to air, as they're on the same vacuum source as the HVAC.

riviera455

today i started to look wat the problem is.
removed the airbox first, the vacuumcanister holds vacuum, the valve was ziptied.so the problem was pretty old.
tomorrow i will see wat the hvac will tell me,
i hope it is just something odd like a broken vacuumline , or one that has been pulled off when someone installed the radio.

@jim,,,that link is awsome, thanks...

Alan

I'd expect the most likely situation is a failure in the sensor loop that caused the mixing flap to be too far open and the water valve to be on regardless of slider position. If the sensor/mixing flaps work - even with the water valve stuck open the temp wouldn't be unbearably hot if the AC works normally.

That its zip tied says that it was unacceptable to someone & since in Belgium it doesn't get really hot (right?) its more likely there is another fault causing excesiive heat.

Vacuum failures alone (watervalve or recirc/distribution flaps) shouldn't create really extreme conditions...

However if the AC does not work - then a stuck water valve may make things uncomfortably hot... see what you have...

Alan

riviera455

it can be verry hot in belgium , 86 in shade and up in summer.
i am sure i have a vacuumleak under the dash, the line that runs to the hcac does not hold vacuum at all.

ac does not work either,,no belt at the comperssor , and i think , but not sure an empty system.
i would love to fix that in the future, but r12 is not availeble at all in europe,so i think i need a complete rebuild system.
the compressor spins freely, that is all i checked out,,,
i cant start for major repairs right now that are less important,,i have to see wat happens when driving the old car. maby it needs more important repairs.

first i would like to drive,,i still have no license plate and insurance,,,dam slow paperwork.

riviera455

just finisched on checking the HVAC vacuum.
all collored lines hold vacuum. the incmming line gives nice vacuum to the HVAC.
the arconditioning does not work,,no belt,,does the outside temp sensor affect the heatersystem to? or does this sensor only work for the ac system?
ill try to check this sensor out ,,,
when i move the buttons from warm to cold and the other selector i cant see anything happen under the dash,,not any vacuumcanister moves. so i think it is elektrical failure.

search continius,,,

riviera455

update,,
i discovered the large black connector (more than ten pins) on the temp selector was not conected,
as soon as i conected this and set egnition on, the fuse blows. so i have some short somewhere. dont know how to find that quick. it might be the selector itselves.

i cant locate the outside temp sensor,it should be somewhere under thye left headlight, dont know how to get there,, have to find out wat wires are running to and see if there is a short.
this will be difficult to find.

riviera455

the problem is bigger than i thought.
someone used an axe i think.
its an 1984

inside the controle unit a diode has blown, this might be a simple replace ,
it is blown but why? can be difficult.
(the diode is now a closed cirquit on the board, currant runs trough)
(if i connect the large connector the fuse blows.maby because of the diode)
at the controle unit someone has cut of the second smaller connector,,i didnt know it should be there until i opend up the unit .
i did not found the removed connector in the car, i only have the rest of the wire bundle.
the wirediagrams dont give me colors in the wires, so a repair will be verry difficult without help or a colored wirediagram.


picture, blown diode,,(blue arrow)


the short connector is missing, on the large connection is a bad connector witch eventualy can be fixed with a jump wire

this is wat is left of the short connector.someone has tried to connect alternative i think,or tried to ,, problem is, i dont know how to reconnect without the connector. i could solder wires and make alternative connections, but need a picture, a collored wirediagram or a cut off connector




if i cant fix this , the only sollution is "heat on" or "heat of" by running a vacuumline to the watervalve,,but i think tha is a stoneage sollution. also no possibility to fix the ac in the future.

Landseer

Are you asking for a picture of the connectors and wire colors?

The ones that attach to the HVAC controller?

For an 84?

I have an 84 in the basement that is undergoing some surgery. The console is removed and the wire connectors are visible.

Just list what you want to see. PM if you want.

What each wire does as it enters a component, I have no idea, though.

riviera455

the picture below is the controle switch seen from above.(black cover removed)
in the upper right corner there should be a connector (marked with a yellow cirkel on my picture)
this is the connector that is missing. note there are two seperated wires on this connector, if you can take a picture with conector installed so i can see wat the beginning and end is at the connector. also normaly the temp controle unit is covered in black plastic, you dont have to remove that , a picture of the conector installed would be fine , as long as i have the colors. ther schould be 9 wires, two could be red,
the connector is at passengers side. please take a few pictures,,could be verry helpfull.


the large connector marked with red is on drivers side, that one i have.

be carefull with these connectors, do not pull lose when not need to. contacts are dammaged easy. oxidation, condence destroys the connector and contacts on the board.

Landseer

There are two connectors, both on the driver's side of the HVAC head.

The third port on the HVAC head, the one you have circled in yellow, doesn't have a harness connector -- it is left open.
(Based on literature and searches, the head changed and the circuits were simplified after 1983 to this configuration. There are 6 solenoid flap actuators for 83, 5 for 84 and on. I think the one that changed is in the console vent.)

In all these pictures, the left is toward back of the car and the right is toward the front of the car.

The connectors are shown in the correct orientation, as if the head was installed.

Does this help? We can probably decipher, also, which wire goes to which connection point on the fuse box, too, if needed.

(Edit, I've figured out most of the 84 wiring diagrams --- but not this one on HVAC --- you are right, the diagram is confusing and doesn't seem to match the layout of the connections)