• Hello Guest, welcome to the initial stages of our new platform!
    You can find some additional information about where we are in the process of migrating the board and setting up our new software here

    Thank you for being a part of our community!

760 ECC

VB242 said:
What is it doing or not doing? I had to replace the vacuum solenoid bank to get mine working correctly.
Click to expand...

Were you able to find a new one?

This car did not have a water valve on it, after installing the water valve I don't see it opening or closing, no movement.
I believe the A/C did work but it has been hacked, pressure switch not in circuit.

Looking at the Green book
https://ozvolvo.org/archive/archive.php?download=VFAzMTA3NS0xXzc2MF93aXJpbmdfZGlhZ3JhbXMucGRm

TP31075-1_760_wiring_diagrams.pdf Not sure this is even the right diagram?

Are there any other manuals I can snag for it?
 
Dirty Rick said:
Were you able to find a new one?

This car did not have a water valve on it, after installing the water valve I don't see it opening or closing, no movement.
I believe the A/C did work but it has been hacked, pressure switch not in circuit.

Looking at the Green book
https://ozvolvo.org/archive/archive.php?download=VFAzMTA3NS0xXzc2MF93aXJpbmdfZGlhZ3JhbXMucGRm



TP31075-1_760_wiring_diagrams.pdf Not sure this is even the right diagram?

Are there any other manuals I can snag for it?
Click to expand...

I got a used one from another member. Before I replaced it I could jury rig it by pushing against the electrical connector. Is the vacuum supply from the intake manifold hooked up and in good shape?
 
Dirty Rick said:
...

Are there any other manuals I can snag for it?
Click to expand...

Look for TP 31127/1. Body fittings. Interior Climate units. Section 8(82-88)

Have the manual but no opinions or experience on the ECC or any 7-series. Read many folks' stories over the years about resoldering the power transistor in the ECC power stage like so many other "relay modules" needed. Possibly they are in the 7/9 FAQs.

I think the transistor just modulates the fan speed.
 
Re-visiting this nightmare.
Car is a somewhat Frankenstein'd 84 760 at the minimum not the original motor.

I have a sensor under the #4 intake runner I don't see this on the ECC schematic I have and believe it is for a different model?
In the diagram I am using all of the temp sensors are inside the car.

sensorvolvo.jpg


I have 4 wires from the AC harness grommet on the firewall, 1 is a call for AC that has been hacked (no pressure switch operation)
I have no idea what the remaining wires are. Large black, small black, and tan?

wiresvolvo.jpg


I am certain the AC clutch should have a pressure switch in series (for safety if nothing else)
 
Last edited:
Pages 217 thru 299 (that cover ACC which is what I have here Not ECC) are missing from TP31127-1

I am looking at the OZ docs, is there another source?
 
The sensor in your intake is the aux fan. It it normally in the top rh end of the rad. There is a good chance I will have a complete working unit later in the month.
 
It appears no heat and some of the doors work. I got defrost airflow but no heat.

I know the AC used to work, but it scares me that the pressure switch was taken out.

I need to spend some more time with it to see what else does not work.

And it would be really nice to find a manual that covers it.
 
Last edited:
I have a complete set of 700 manuals, will see if I have any info that hasn't already been covered here. I got the ACC working on my '83 and a couple of '84s I have had, didn't take that much effort on any of them.

Works pretty well when it's going good but the one thing I don't like about the basic design is it gives you no ability to control fan speed independent of temp setting. If you want full hot air but medium fan speed, you can't have it since if you crank the temp wheel up it will blast the fan. The low fan speed setting is too low to keep windshield clear in cold and damp weather so it's either full blast fan or effectively nothing.

A couple years ago after studying the internal circuits of the head unit enough, I figured out how to swap the blower motor resistor wires around so that the "auto" setting locks the fan onto medium speed and prevents automatic control regardless of the temp setting. This effectively makes it so the fan speed is all manually controlled, with 3 speeds: "Lo" is low speed, "Auto" is medium and "Hi" is full speed. The auto temp wheel just takes care of the air temperature and can't influence fan speed. Worked great and made the car a lot nicer to use in the winter. In the end I think the actual wiring change was just swapping one connection in one of the plugs that's easily accessible with the glovebox out. If you are interested in doing similar I could probably figure out again what the change was and put up a couple pictures.

The system is pretty simple, bet you will be able to get it working good with a little poking and prodding. Remember that the system is built to default to full heat and full defrost if there is no vacuum being provided to the unit. You're sure the little vacuum line that goes through the firewall to run the system is intact and no leaks?

Do you have a heater control valve still? If so is it staying open when you are asking for heat or is it getting vacuum? What other stuff is hacked on it besides the AC switch?
 
I am hesitant to tear into it without service info. I got roped into working on it.
I installed a heater valve when I reinstalled the motor and it now has no heat.
Since the valve defaults to open I assume it is getting vacuum.

15A PM'd me with a manual for sale I'll follow through on that since it seems the system can be worked on.
I like your idea of the fan speed control.
First thing I noticed was the defrost airflow is not widely distributed and hampered by a Dashmate.
Any clues on the three wires? (engine side see pic)
I also have a single wire temp sensor in the other heater hose (I have a feeling that is some hackery to bypass the missing heater valve)
 
The manual will help you with some of those questions if you can get one. The single wire temp sensor inline in the heater hose is an on/off switch that is meant to prevent the hvac fan from running until engine temperature rises above a certain point. It should have a ground wire with bare spade terminal attached to ground the union pipe on the other side from where the temp switch screws in, then an insulated spade terminal connection on the switch terminal. I'll have to look at my car to remember the color of that wire, it might be one of the two in your picture.

Does the HVAC fan run as intended on yours? If it does then this switch is already hooked up correctly or bypassed. I bypassed it on mine, just a jumper wire between the two female connections does the job without cutting anything. Works better that way.

As you said, the heater control valve should default to open with no vacuum and IIRC the only time it ever actually closes is when you have it in the max A/C recirc setting. If you had heat before and lost it only after installing the heater control valve, it means one of three things is going on: 1) the valve you put in is incorrect and defaulting to closed position, or 2) it's getting vacuum and closing when it shouldn't, or 3) when it was installed, an air pocket got into the heater core that needs to be burped out. Do you have vacuum at the line to the heater control valve? Can you confirm it's not closed and preventing coolant from circulating thru the core?

If you end up isolating the issue to the control unit and need another one, I have a couple spares of those.
 
GOt the manual sadly it is a mechanical manual and has not wiring diagrams.

Blend door is not moving. I jumpered the temp switch wires at the heater valve and the blower comes on. The metal relay above the blower motor next to the cube relay behind the glove box is buzzing (wonky) when switched to off position.
After running it a bit for diagnostics it tried to let the magic smoke out and the pink wire from the cube relay behind the glove box got fairly hot.
I'm thoroughly disgusted with whomever butchered this system.

Is the ECU that mounts in the pass kick panel for the climate control or for the motor? (25 pin connector)
Or are all the electronics for the ACC in the programmer module?

I'm regretting even looking at this more now than before with no manual.... :^(
I'm really regretting this when I discovered that you have to pull the console and the radio and some of the ducting to remove the third mounting screw for the programmer module. FML
 
Last edited:
OK got the programmer/servo out and the vacuum chamber does not hold vacuum. Check valve on the back of the diaphragm was leaking. But it does not look complete? Is something missing? No Part # on it either?

servo.jpg
 
You must log in or register to reply here.
Back
Top