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 Post subject: Re: Hot and Cold air blower workings?
PostPosted: Thu Dec 05, 2019 12:37 pm 
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The one at the end of the tube from the rosette in the dash has the thermistor as part of the fan unit at the end

If you pull the tube off the end is probably stuffed with fluff, pick this out carefully as the thermistor is buried in it

They are all replaceable by the way I have a bag of them some where

Make sure the fan is running when the ignition is on

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 Post subject: Re: Hot and Cold air blower workings?
PostPosted: Sat Dec 14, 2019 9:25 pm 
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A bit of an update, I have not had much time to work on this with car being outside at the moment and the weather being as terrible as it has.

I have tested both the solenoids under the dash at he drivers footwell and they both are clicking with 12v on them. I forgot to test whether they are getting voltage from the control unit, I will check this before I fit them back on the heater box.

I have also looked behind the dash where the round vent is to see if there is a sensor but again there seems to be nothing, it even has a blanking plug in the rear of it. There doesn't seem to be anything dropped down behind it either.

Image

I've pulled the blanking plug out a little to show it better.

Image

The one that is supposed to be near the wiper motor also doesn't seem the be there, I have a plug from the wiring loom but nothing on the end of it or close by.

I have eventually removed the fan cover, there were two screws under the scuttle without the cross head on them due to the decades of compost behind the fan box. I managed to get one off with a impact driver but I had to get a hacksaw blade in to cut the head off the other, it was a real pain in this cold weather. I wanted to remove it just to see there was nothing hiding inside and it will allow me to clean the mulch behind it.
While is was in this area I tested the vacuum valves that operate the fresh air flaps, the nearside one worked when I sucked on the pipe but the offside one didn't move and felt seized. I removed it and it moved fine and blew air out of the end pipe so it led me to think it was OK. I decided to spray a little WD40 into the rod/thread end it and blew fluid out of the vac pipe end leading me to believe the diaphragm to be holed. I will order a new or used one of these anyway.

Image

My question, is this enough to stop the whole vacuum system not working., I would assume so?


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 Post subject: Re: Hot and Cold air blower workings?
PostPosted: Sun Dec 15, 2019 3:29 pm 
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Oh yes indeed, you short some sensors

That bung is not right,

This is an oval dash car correct,
Are there any loose connectors behind the glove box there should be a tube fan connected to the back of the rosette by a short rubber hose
This senses the cabin temp, the one under the bonnet senses the air intake temp, on the 968 there is also one in the NS door mirror, and one inside the main mixing chamber of the heater box

I can post up some pics of the bits your missing tomorrow
Where are you located? Bet your miles from me

I'm in Essex

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2013 A4 177 TDI Quattro Ibis White
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 Post subject: Re: Hot and Cold air blower workings?
PostPosted: Sun Dec 15, 2019 5:04 pm 
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Without the sensors, the heater will default to heat. So yes, you will need the missing sensors.

What 944 is this?


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 Post subject: Re: Hot and Cold air blower workings?
PostPosted: Sun Dec 15, 2019 6:09 pm 
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Hi guys, just a thought...if the unit being talked about here is a standard heater, then they are not fitted with all the sensors. Those are used in the climate control version and AC units. I went through this exercise when I had heater issues and couldn't find the sensors shown in the circuit diagram. Someone in the states pointed out my mistake, and it all made sense. Apparently the front panel of the standard heater has the graduated blue to red dial, the climate control has numbers. :)

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 Post subject: Re: Hot and Cold air blower workings?
PostPosted: Sun Dec 15, 2019 6:29 pm 
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To my knowledge, all 944 oval dash heater controls have the 3 sensors; with or without AC. If you look up any explanation on Clark's garage or other, it is explained on there.

Sorry to ask again, but you haven't replied; what 944 do you have?


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 Post subject: Re: Hot and Cold air blower workings?
PostPosted: Sun Dec 15, 2019 6:31 pm 
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Rhett wrote:
Hi guys, just a thought...if the unit being talked about here is a standard heater, then they are not fitted with all the sensors. Those are used in the climate control version and AC units. I went through this exercise when I had heater issues and couldn't find the sensors shown in the circuit diagram. Someone in the states pointed out my mistake, and it all made sense. Apparently the front panel of the standard heater has the graduated blue to red dial, the climate control has numbers. :)


Does yours just have a graduated blue to red dial?


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 Post subject: Re: Hot and Cold air blower workings?
PostPosted: Sun Dec 15, 2019 6:36 pm 
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Rhett wrote:
Hi guys, just a thought...if the unit being talked about here is a standard heater, then they are not fitted with all the sensors. Those are used in the climate control version and AC units. I went through this exercise when I had heater issues and couldn't find the sensors shown in the circuit diagram. Someone in the states pointed out my mistake, and it all made sense. Apparently the front panel of the standard heater has the graduated blue to red dial, the climate control has numbers. :)


You may be right on this as my non-AC heater control did have temperature numbers on the control as well!


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 Post subject: Re: Hot and Cold air blower workings?
PostPosted: Mon Dec 16, 2019 3:35 pm 
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Hi all, sorry for the late reply and thanks for the info, I was out and about all day and night on Sunday so have only just had time to reply.

My car is an 1986 S, Oval dash, it also does have the graduated blue to Red on the temp knob rather than the number so hopefully I don't have anything missing?

The bung in the rear of where the sensor should be does look factory to me and with the other sensors missing I would hope this is one car without the sensors.

My Vac valve doesn't arrive until the end of the week so I will report back with the results of that, if it still doesn't work I will assume its the control unit at fault as everything else seems to be in place and working.

Waylander, yes I'm miles away, in the East Mids.


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 Post subject: Re: Hot and Cold air blower workings?
PostPosted: Mon Dec 16, 2019 3:43 pm 
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infrasilver wrote:
Hi all, sorry for the late reply and thanks for the info, I was out and about all day and night on Sunday so have only just had time to reply.

My car is an 1986 S, Oval dash, it also does have the graduated blue to Red on the temp knob rather than the number so hopefully I don't have anything missing?

The bung in the rear of where the sensor should be does look factory to me and with the other sensors missing I would hope this is one car without the sensors.

My Vac valve doesn't arrive until the end of the week so I will report back with the results of that, if it still doesn't work I will assume its the control unit at fault as everything else seems to be in place and working.

Waylander, yes I'm miles away, in the East Mids.


It does make sense that without temperature control on the control unit, there may not be any temp sensors!


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 Post subject: Re: Hot and Cold air blower workings?
PostPosted: Thu Jan 02, 2020 9:03 pm 
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Just a little update from last week. I have replaced my offside vacuum solenoid but that didn't fix the issue, I am now assuming I have run out of other things to test so will now need to change the control unit out? I don't have enough knowledge to test it and as it seems to be not operating any of the buttons, (recirculate and screen clear) plus the temp dial and both sliders don't seem to do anything, I think it may be faulty?

Also while I'm on, this is the connector where it looks like a sensor may go but as I mentioned there is nothing in this location for it to be connected to, it must be just part of the standard loom?

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 Post subject: Re: Hot and Cold air blower workings?
PostPosted: Thu Jan 02, 2020 9:48 pm 
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What year is the car, I might have missed that in the thread somewhere

The answer to your question about it might not be fitted and the connection is there just for fun can only be confirmed by other owners of cars without, I dont think there were any 85.5>> cars without

If it was just for fun Porsche are very good about fitting blanking plugs in these holes, I have never seen another picture of a blanking plug behind the rosette.

And let’s be fair it’s not a good fit.

As I said before I have a spare controller, if you want to borrow it, just cover the post

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1985 Honda VF1000 F2 Bol D'or In Silver
2013 A4 177 TDI Quattro Ibis White
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 Post subject: Re: Hot and Cold air blower workings?
PostPosted: Thu Jan 02, 2020 10:13 pm 
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It's an October 86 S, an early 85.5

The bung in the back of the rosette is pulled out for the photo but is flush and a perfect fit once pushed home. There are no connections around the area's that folk are saying something should be so I'm happy there isn't anything to connect and I'm sure it's like that from the factory just from looking at it?

I will PM you regarding the control unit, I'm guessing your's has the numbers on the heat knob, either way It'll be good to change it out for a known working one even if some features don't work?


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 Post subject: Re: Hot and Cold air blower workings?
PostPosted: Tue Jan 07, 2020 11:52 pm 
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I got the control unit from Waylander today, much appreciated, as it saved me the cost of buying one to find out that this doesn't seem to be the problem either. The unit just does the same as my own one, where the fan speed works and that is all. I'm almost stumped now but may have to change the actuators down by the passengers feet, again just to eliminate them. Again I'll report back.


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 Post subject: Re: Hot and Cold air blower workings?
PostPosted: Wed Jan 08, 2020 9:27 am 
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Just a query; was the controller you received from Waylander, an AC unit? Have no idea if this makes any difference but I do have a temperature controller that is not an AC unit if you would need to borrow.


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