robot808

Does anyone know the difference between the HVAC control head for a manual versus an automatic? I have an '82 Manual and I need to replace the control unit. There is a used one on ebay for the same MY but it has the automatic part number. The a/c has been deleted from my car, so I really just need the heat to work. I am just outside of Chicago and it gets a bit chilly.
As always, thanks for any help.

largecar379

don't know of any difference between control units (auto or manual), but the heater should still work even if the A/C doesn't....

Assuming you didn't change anything (control unit, heater valve, vacuum lines, etc), you'll just have to go down through the list of suspects......

--Russ

John Veninger

I have a Euro version from 1980, $75.00+ shipping
What does your's look like? How do you know its bad? You car has a manual controller?

robot808

I mean to say that my car is a 5 speed. The part numbers for the head unit for the stick and the automatics are different. I was kind of hoping that I could use the automatic, because they are easier to find/cheaper.
John, if your's would work, I would take it. It looks the same but in Fahrenheit. I was hoping that the difference between the part for the auto and the part for the stick might be a/c related since I don't have a/c anyway.
I am not 100% sure that the problem is the head unit, but I have tried following Wally's instructions to track down the problem, and it seems that it is the most likely source. The blower motor does work when directly powered. I have tried new relays & new fuses. I have tried Wally's trick with a jumper in the relay and the fan does kick on with that in place.
The head unit seems to be the most likely source of trouble to me now. Unless anyone has a better idea...
Thanks again,

nosnow

I have an 82 5-speed and I had the opposite problem. My Heat wouldn't turn off. Have you checked to make sure the heater valve is not tied in the close position? There is a relay in the head unit that goes bad and that may cause your problem but I think when that goes bad it defaults to heat.

Personally, I'd pull the air cleaner and verify that your heater valve is working properly before spending money on a new head unit.

robot808

well, I do have an extra heater control valve laying around so I will try that, but I am fairly convinced it is the head unit. I will let you know as soon as I am done with it.
in the meantime, does anyone know about the differences in the controls?
thanks again,

nosnow

When I was saying test I didn't mean swap. Just apply some vacuum to it to verify functionality. If you disconnect the vacuum lead you should have heat as the default is open or heat on. This will at least help trouble shoot it down to head unit or not.

Not sure about the diferences in head units. I would suggest going to 928 intl and looking at the various parts, that will at least tell you what years will interchange with your car. I know that some cars had an a/c button and some had full blown climate control. I assume there was an option package for this feature.

robot808

paul, thank you. I do see what you saying. I will try that and I will probably put in the new one WIAIT.
still looking for ideas on the different head units.
thanks to all.

Alan

I don't believe there was any difference in HVAC head unit between auto & manual transmission cars in any year.

I believe some very early cars (without AC) had manually operated heater only flap controls (by levers & mechanical connections) ... so this may be listed as Auto/Manual referring to the control units not the car's transmisson.

Alan

Jim bailey - 928 International

The reference to manual or automatic really is about the climate control function. If it has numbers above the slider it is a climate control unit where you set the desired temperature and the unit regulates the flow of water,outside air and a/c to maintain that temperature. Most 928s by 1980 especially in the US have climate control. The 1980- 1983.5 is the 928 573 060 05. The 1983.5 after vin # 92 DS 861952 uses the 09 version. They will not interchange . The early manual unit is completely different from the climate control units.

robot808

guys, thank you. that makes an overwhelming amount of sense. although I do feel a little extra stupid, this information is an extraordinary help.

Jim bailey - 928 International

Now about getting some heat ! If you unplug the small hose from the heater valve it defaults to open (unless wired shut ) and the heater core will get hot with a fair amount perculating into the car. Getting the blower to blow will greatly increase the heat . That could be done with a jumper from the post near the radiator back to the plug for the blower just be sure to fuse the wire..... Rude and crude but better than freezing

robot808

Paul,
I did check the heater control valve, appears to be working fine.
Jim,
Those are great tricks. I just used them both with great results. I feel a little ghetto having to open the hood to connect and disconnect the wire since the post has power with the car on or off. This will get me through until I get I get it fixed right though.

Thank you so much.

Nicole

I love the idea of having metric numbers on the climate control. What does Fahrenheit mean anyway...

brutus

i think it means you just sneezed.