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Brockoli · Posted: Thu Dec 06, 2007 11:36 am Post subject: Fresh air blower/ heater core

Has anyone taken out the fresh air blower motor/fan? I can see it from the engine bay but there is a plastic gaurd, so I dont think it can be removed that way. I have started to take apart the console/glove box and cant seem to pull the complete ventilation system out the passenger side. Do I have to take out the metal cross member that goes under the glove box or is there an easier way that I have not thought of? Otherwise I think I have to take the dash board and metal cross member out to get the entire thing out. I need to replace my fresh air blower/ fix my heater so I have heat. ANy help would be appreciated!!!
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'80 924 M471,Wideband O2, Full coilover susp,23/19 sways,Bilstiens,KLA Strut Brace,Roll Bar,Test Pipe,BBS RS, Willwood BBK

25% of a '87 944 Chumpcar http://straightpipe.ca/forums/showthread.php?t=2454

'79 924 Sebring Edition(Sitting)

!tom · Posted: Fri Dec 07, 2007 2:31 am Post subject:

There is no easy way. It involves removal of the dash, and just about every other part of the car.
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78 924 NA
5-lug

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

Don't listen to !tom, he's a big crybaby. . .

Totally easy, here is all you have to do (clickable thumbs):

Good luck!

In all seriousness, though, my car has A/C, which made it necessary to do all the dismantling in the pictures. If yours doesn't, according to the Porsche FSM, you should be able to remove the console, glove box, heater core (remove side cover, unbolt flange, slide core out), and the box behind the center vents (called "mixing chamber", held on by one small nut), then withdraw the box through the passenger foot well.
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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

Brockoli · Posted: Sat Dec 08, 2007 10:07 am Post subject:

unfortunatley my '79 does have a/c. But my '77 doesnt, which is the car im gunna scavenge the vent. system from. The '79 A/C unit doesnt work so i might not put it back in, I take it from reading other threads that when u have a/c the power to your fresh air blower is somehow tied in to the power to the A/C fan. Is this right? If i take out the complete A/C system will the original wiring still work for the heater/ fresh air blower?

The other down side is that it is -15 Celcius today and I'm in a garage with no insulation/heat. But it is much warmer than is has been all week
(-25ish).
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'80 924 M471,Wideband O2, Full coilover susp,23/19 sways,Bilstiens,KLA Strut Brace,Roll Bar,Test Pipe,BBS RS, Willwood BBK

25% of a '87 944 Chumpcar http://straightpipe.ca/forums/showthread.php?t=2454

'79 924 Sebring Edition(Sitting)

mgatlag · Joined: 02 Aug 2007 Posts: 647 Location: Avon, IN

I just got done getting my heater to work in my 77.5 na after the AC was removed. After a bunch of questions and the guys here giving input, i have it working. The power for the blower motor does go through the AC switch but you can make the heater work and it's easier than you think. What kinds of questions do you have?
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Michael
'77 1/2 924 N/A- 5 speed Audi box
'04 Ford Taurus - gone!!
'92 Jeep Cherokee Laredo - gone!!

Porsche... better than tea with Miss McGill
(Slap Shot)

Brockoli · Posted: Mon Dec 10, 2007 8:44 am Post subject:

im contemplating if i should take out the A/C system. I dont think i will get it operational because i think it will cost too much for what it is worth. Also, since im taking out the entire dash board/ A/c system to get fresh air blower out I dont think it will be worth putting everything back in place if I'm not gunna use it.

So, if I take the A/C system out do I have to rewire the system so that the heater fan still gets power, if so how? Im still taking everything apart so im not too deep into this problem yet but I will be very soon, any suggestions now will make it easier when I am under the dash elbow deep in wiring and vents!!!!
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'80 924 M471,Wideband O2, Full coilover susp,23/19 sways,Bilstiens,KLA Strut Brace,Roll Bar,Test Pipe,BBS RS, Willwood BBK

25% of a '87 944 Chumpcar http://straightpipe.ca/forums/showthread.php?t=2454

'79 924 Sebring Edition(Sitting)

mgatlag · Joined: 02 Aug 2007 Posts: 647 Location: Avon, IN

My AC was completely removed several years ago since it was going to be too expensive to repair it and probably not worth the hassle. When I got my heater working again, the wiring was a bit challenging but after I figured it out, it was pretty simple.
Coming out of the fuse box, find the fuse that brings power to the blower fan. Should be a red wire and a ground (brn) that goes to the blower motor. Mine did have AC so I had to find where the red wire and where it was wired into a relay for AC system that was apparently put in by the dealership. i cut it and made sure the wire continued on to the blower motor. From the blower, 2 ground wires came back down. A brn/wht and a brn/blk. These wires would go to the heater control assembly and controlled the speeds of the fan. I started a thread about all this and had some great responses, so if this doesn't help enough, find the thread I posted about 3 weeks ago. I'm a little computer retarded so sorry I can't include it here. Let me know if this helps or need to see some of my pics I took along the way.
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Michael
'77 1/2 924 N/A- 5 speed Audi box
'04 Ford Taurus - gone!!
'92 Jeep Cherokee Laredo - gone!!

Porsche... better than tea with Miss McGill
(Slap Shot)

Brockoli · Posted: Thu Jan 03, 2008 11:26 am Post subject:

So i finally have time to work on the car. I took out the A/C stuff under the dashboard and now have to figure out the wiring.

I have extra relays under the dash by my right knee with these wires coming out of them...

relay #1 red/brown, black/white, red, blue white

relay #2 red/blue, red, brown, black/yellow

MGATLAG:

Question #1:you said in your last post that you cut the red wire that was wired into the extra relay. Which relay was that?

Question #2:When you traced your wires from the fuse board did you unwrap all the wires to find yours or did you have a shourtcut?Do I have to unwrap the wiring harness?

I have read the wiring diagrams in the haynes manual and the wires for the fresh air blower come from fuse 10 (16A).

Question #3:So, when the dealership put in the A/C where did they splice into the circuit that includes fuse 10?

I have the proper wires going to my heater assembly, according to the picture from rasta from your previous thread.

Thank you for your help so far, hopefully you can help me with my questions. If you want to call me to make this easier fell free to do so.
Brock @ 780-473-6858
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'80 924 M471,Wideband O2, Full coilover susp,23/19 sways,Bilstiens,KLA Strut Brace,Roll Bar,Test Pipe,BBS RS, Willwood BBK

25% of a '87 944 Chumpcar http://straightpipe.ca/forums/showthread.php?t=2454

'79 924 Sebring Edition(Sitting)

Buwani 931 · Joined: 31 May 2004 Posts: 308 Location: Napa California