Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Technical BBS > 1- Porsche Technical Forums > Porsche 911 Technical Forum

Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Registered User
 
Join Date: Oct 2000
Location: Nearby
Posts: 42,727
Garage
Send a message via AIM to fintstone
Footwell Blowers

Since there seems almost a universal misunderstanding about how these work due to the odd design and poor schematics, I decided to draw it out in a simplified diagram. Please let me know if I have made any errors.



Note:
when the heat control switch is in:
- position 1, 12v is applied through both resistors in the resistor assembly causing the fans to run slowly (voltage drop)
The Aux blower relay remains open (no ground at pin 85)

- position 2, 12v is applied through only one resistor in the resistor assembly. Less resistance causes the fans to run faster. (Less voltage drop)
The Aux blower relay remains open (no ground at pin 85)

- position 3, 12v is removed from the resistor assembly.
Ground is applied to pin 85 of the Aux blower relay which closes it and allows 12v to pass to the fans without going through the resistor assembly...fan runs at full speed.
__________________
74 Targa 3.0, 89 Carrera, 04 Cayenne Turbo
http://www.pelicanparts.com/gallery/fintstone/
"The problem with socialism is that you eventually run out of other people's money"
Some are born free. Some have freedom thrust upon them. Others simply surrender
Old 02-21-2004, 07:31 AM
  Pelican Parts Technical Article Directory    Reply With Quote #1 (permalink)
Back in the saddle again
 
masraum's Avatar
 
Join Date: Oct 2001
Location: Houston, TX
Posts: 27,807
Where's the switch that is triggered by the two red levers? I know it's there, I've seen it and manually operated the thing, so I am certain that it is for the heat.
__________________
Steve
'08 Boxster RS60 Spyder #0099/1960
- never named a car before, but this is Charlotte.
'88 targa SOLD 2004 - gone but not forgotten
Old 02-21-2004, 07:57 AM
  Pelican Parts Technical Article Directory    Reply With Quote #2 (permalink)
A Marchand fan before you
 
Por_sha911's Avatar
 
Join Date: Dec 2003
Location: TN
Posts: 11,035
Garage
My `87 has the in-line fuses as well
__________________
--------------------------------------
Joe
See Porsche run. Run, Porsche, Run: `87 911 Carrera
Old 02-21-2004, 08:02 AM
  Pelican Parts Technical Article Directory    Reply With Quote #3 (permalink)
Registered User
 
Join Date: Oct 2000
Location: Nearby
Posts: 42,727
Garage
Send a message via AIM to fintstone
Steve..this is intentionally only for the manual footwell blowers, not the entire heating system. The switch you refer to turns on the blower motor on the engine via the engine compartment relay.
Joe...They supposedly only came in the '88 and '89 cars. The Factory issued a supplement (fire hazard)to add them to the earlier cars....Perhaps a previous owner did..or it was still on the lot when the supplement came out and the dealer did it. Are you the original owner?
__________________
74 Targa 3.0, 89 Carrera, 04 Cayenne Turbo
http://www.pelicanparts.com/gallery/fintstone/
"The problem with socialism is that you eventually run out of other people's money"
Some are born free. Some have freedom thrust upon them. Others simply surrender
Old 02-21-2004, 08:29 AM
  Pelican Parts Technical Article Directory    Reply With Quote #4 (permalink)
Registered User
 
Join Date: Dec 1969
Location: Lac La Biche, Alberta, Canada
Posts: 951
In my 86 with manual heat, the footwell blowers come on low at both "0" and "1".

I also think your missing the connection between position 1 of the switch and pin 86 of the relay. Also the diode on the same line just before the 2.3 ohm resistor.



Good work!

Tim

Last edited by Tim Polzin; 02-21-2004 at 09:17 AM..
Old 02-21-2004, 09:06 AM
  Pelican Parts Technical Article Directory    Reply With Quote #5 (permalink)
Registered User
 
Join Date: Oct 2000
Location: Nearby
Posts: 42,727
Garage
Send a message via AIM to fintstone
Tim
Thanks..This is a drawing from an '84. Looks like they added the diode in '85 (at least in the schematic).
As far as the connection between position 1 of the switch and pin 85 of the relay. I see that in my '85 schematic, but believe it to be an error. I think they have switched pin 85 and 86 in that drawing because: 1. it is switched from previous years 2. IMHO, it would not work and goes against normal Bosche relay convention. I would be interested if anyone has ever verified this connection. Alas, I am too poor to own anything newer than a '74 so I cant verify it myself.
__________________
74 Targa 3.0, 89 Carrera, 04 Cayenne Turbo
http://www.pelicanparts.com/gallery/fintstone/
"The problem with socialism is that you eventually run out of other people's money"
Some are born free. Some have freedom thrust upon them. Others simply surrender
Old 02-21-2004, 09:47 AM
  Pelican Parts Technical Article Directory    Reply With Quote #6 (permalink)
Registered User
 
Join Date: Dec 1969
Location: Lac La Biche, Alberta, Canada
Posts: 951
You may be right on the error. I noticed a couple of other Bentley errors in wiring for the later DME as well. It really is amazing the convolutions used to achieve minimal tasks.

Now if the roads ever dried up enough to actually drive the freaking car.

Tim
Old 02-21-2004, 10:22 AM
  Pelican Parts Technical Article Directory    Reply With Quote #7 (permalink)
Back in the saddle again
 
masraum's Avatar
 
Join Date: Oct 2001
Location: Houston, TX
Posts: 27,807
Yes, position 0 and 1 are both "low".
__________________
Steve
'08 Boxster RS60 Spyder #0099/1960
- never named a car before, but this is Charlotte.
'88 targa SOLD 2004 - gone but not forgotten
Old 02-21-2004, 10:27 AM
  Pelican Parts Technical Article Directory    Reply With Quote #8 (permalink)
Registered User
 
Join Date: Oct 2000
Location: Nearby
Posts: 42,727
Garage
Send a message via AIM to fintstone
Very interesting. Is this just certain years? Steve/Tim...do you have automatic or manual systems? Joe, what about your '87? That is an '86 and an '88. Anyone have an '84 or an '83 turbo with footwell blowers for comparison??
__________________
74 Targa 3.0, 89 Carrera, 04 Cayenne Turbo
http://www.pelicanparts.com/gallery/fintstone/
"The problem with socialism is that you eventually run out of other people's money"
Some are born free. Some have freedom thrust upon them. Others simply surrender
Old 02-21-2004, 11:46 AM
  Pelican Parts Technical Article Directory    Reply With Quote #9 (permalink)
Registered User
 
3.2 CAB's Avatar
 
Join Date: Dec 2003
Location: MS.
Posts: 2,322
Gee, tell me how to make them work in a 77' Targa. I have a project I am working on. The footwell panels were different before then. If any of you P people can help, let me know.
__________________
84' Steelslantnose Cab.
1953 Dodge B-4-B-108" 90,127 miles
1953 Dodge B-4-C-116" 58,146 miles
1954 Dodge C-1-B8-108" 241V8 POLY
1973 Roadrunner 440-SIX-PACK*
1986 F-250 Super Cab-460 V8 tow
Newest additions-
Matching numbers 1973 340 Road Runner!!
1948 Dodge B-1-F-152" 1-1/2 ton Dump body, 39,690 miles
others...
Old 02-21-2004, 04:57 PM
  Pelican Parts Technical Article Directory    Reply With Quote #10 (permalink)
Registered User
 
greglepore's Avatar
 
Join Date: Mar 2003
Location: SE Pa USA
Posts: 2,917
Finstone-for the schematically challenged, 'splain to me why mine run most of the time only on position 2, intermitently on 1 & 3, whilst the switches behind the handbrake test good all the time. There's a case of your favorite microbrew in store for you if you can solve this.
__________________
Greg Lepore
85 Targa
05 Ducati 749s (wrecked, stupidly)
2000 K1200rs (gone, due to above)
Old 02-21-2004, 05:33 PM
  Pelican Parts Technical Article Directory    Reply With Quote #11 (permalink)
Registered User
 
Join Date: Oct 2000
Location: Nearby
Posts: 42,727
Garage
Send a message via AIM to fintstone
Gregg
I would guess you have a intermittant connection at the 6 pin connector that plugs into the heating control unit between the seats (The pin connected to 2 black wires) or somewhere in the vicinity (perhaps actually where the wires actually attach to the switch).
One way of troubleshooting this,problem is by pulling up the Aux fan relay (in the front trunk) in its connector til you can put a meter or test light on the pins. You should have 12v at pin 30, 86 and 87 , ground at 85 when in position 3. In your case, I suspect you are missing the 12v at pin 86.
__________________
74 Targa 3.0, 89 Carrera, 04 Cayenne Turbo
http://www.pelicanparts.com/gallery/fintstone/
"The problem with socialism is that you eventually run out of other people's money"
Some are born free. Some have freedom thrust upon them. Others simply surrender
Old 02-21-2004, 08:04 PM
  Pelican Parts Technical Article Directory    Reply With Quote #12 (permalink)
 
Now Available for Ordering:   101 Projects For Your BMW 3 Series 1982-2000  [more info]
Registered User
 
Join Date: Oct 2000
Location: Nearby
Posts: 42,727
Garage
Send a message via AIM to fintstone
3.2 cab
Depends exacly what you are looking for. The easiest wey to install them is to get the footwell carpets from 84-89 car. They are formed with a space behind them. You should be able to graft theblowers right into you existing pumbing. Personally, for simplicity, I would probably just wire them in with an on/off switch and a relay so you would ony be able to operate them on high, but you could certainly take the resistor assembly and switch off another car.
__________________
74 Targa 3.0, 89 Carrera, 04 Cayenne Turbo
http://www.pelicanparts.com/gallery/fintstone/
"The problem with socialism is that you eventually run out of other people's money"
Some are born free. Some have freedom thrust upon them. Others simply surrender
Old 02-21-2004, 08:13 PM
  Pelican Parts Technical Article Directory    Reply With Quote #13 (permalink)
Registered User
 
3.2 CAB's Avatar
 
Join Date: Dec 2003
Location: MS.
Posts: 2,322
Flintstone, that was how I was thinking of doing it. I know the panels in my 84 have the bulge in them and the 77 are sort of flat.
__________________
84' Steelslantnose Cab.
1953 Dodge B-4-B-108" 90,127 miles
1953 Dodge B-4-C-116" 58,146 miles
1954 Dodge C-1-B8-108" 241V8 POLY
1973 Roadrunner 440-SIX-PACK*
1986 F-250 Super Cab-460 V8 tow
Newest additions-
Matching numbers 1973 340 Road Runner!!
1948 Dodge B-1-F-152" 1-1/2 ton Dump body, 39,690 miles
others...
Old 02-22-2004, 03:14 AM
  Pelican Parts Technical Article Directory    Reply With Quote #14 (permalink)
Registered User
 
greglepore's Avatar
 
Join Date: Mar 2003
Location: SE Pa USA
Posts: 2,917
Thanks. I'll check that.
__________________
Greg Lepore
85 Targa
05 Ducati 749s (wrecked, stupidly)
2000 K1200rs (gone, due to above)
Old 02-22-2004, 04:32 AM
  Pelican Parts Technical Article Directory    Reply With Quote #15 (permalink)
Registered User
 
Join Date: Oct 2000
Location: Nearby
Posts: 42,727
Garage
Send a message via AIM to fintstone
3.2 Cab
I have most of the used parts to do that with in my garage in a box..including the later footwell panels in black. If you decide to do it and need them, I could give you a decent price. I will probably put them on the sale listing eventually. I decided not install them myself since it just doesn't get very cold here and with SSIs, I have more than enough heat. I think I will concentrate on building a top-notch A/C instead.
__________________
74 Targa 3.0, 89 Carrera, 04 Cayenne Turbo
http://www.pelicanparts.com/gallery/fintstone/
"The problem with socialism is that you eventually run out of other people's money"
Some are born free. Some have freedom thrust upon them. Others simply surrender
Old 02-22-2004, 08:08 AM
  Pelican Parts Technical Article Directory    Reply With Quote #16 (permalink)
Registered User
 
Join Date: Aug 2002
Location: Orchard Park, NY
Posts: 10,522
10A footwell blower fuses appeared on 87 production run...and oddly show up on the 88 and later factory manual wiring schematics. Maybe they were a run-in during 87.


---Wil Ferch
__________________
Wil Ferch
85 Carrera ( gone, but not forgotten )
Old 02-22-2004, 09:47 AM
  Pelican Parts Technical Article Directory    Reply With Quote #17 (permalink)
Registered User
 
3.2 CAB's Avatar
 
Join Date: Dec 2003
Location: MS.
Posts: 2,322
Flintstone, I sent you a PM.
__________________
84' Steelslantnose Cab.
1953 Dodge B-4-B-108" 90,127 miles
1953 Dodge B-4-C-116" 58,146 miles
1954 Dodge C-1-B8-108" 241V8 POLY
1973 Roadrunner 440-SIX-PACK*
1986 F-250 Super Cab-460 V8 tow
Newest additions-
Matching numbers 1973 340 Road Runner!!
1948 Dodge B-1-F-152" 1-1/2 ton Dump body, 39,690 miles
others...
Old 02-22-2004, 09:57 AM
  Pelican Parts Technical Article Directory    Reply With Quote #18 (permalink)
 
Now available:  101 Projects for Your Porsche Boxster!
Registered User
 
'89cab's Avatar
 
Join Date: Feb 2003
Location: Carmel CA
Posts: 250
Garage
Flintstone:
Thanks for your fine work. I appreciate the direction you gave me last weekend (on my footwell blowers that wonít shut off). Weather and work have prevented me from tackling the problem. My current best guess is that a previous owner/mechanic rewired the motors to another power source. Libby O directed me to this site which indicates that Libby and I are not the first to have motors running all the time.
http://www.porschenet.com/bruns02.html

Iím now just using engine blower and it is not too bad. I hope to trace the problem down this weekend. Iíll be using your info as well as the Bentley manual, I also found following diagram somewhat helpful:
http://www.type-911.co.uk/images/exhausts/heatingtech5.jpg
__________________
'89 cab
Old 02-22-2004, 06:57 PM
  Pelican Parts Technical Article Directory    Reply With Quote #19 (permalink)
Registered User
 
Join Date: Oct 2000
Location: Nearby
Posts: 42,727
Garage
Send a message via AIM to fintstone
89 cab
After thinking a bit more about your problem....I had a thought. The engine compartment controller actually has unswitched power. If it shorted out so that you had 12v at pin 4 with the key off..it would also cause your problem...without a rewired sytem. You can check for that by testing pin 4 of the engine compartment controller or pin 86 of the aux blower relay in the front trunk for voltage when the key is off. Something that threw me off is that I have never seen anything before that indicated that the later cars, the fans still run on low in position 0 (with ignition on), but apparently they do.
__________________
74 Targa 3.0, 89 Carrera, 04 Cayenne Turbo
http://www.pelicanparts.com/gallery/fintstone/
"The problem with socialism is that you eventually run out of other people's money"
Some are born free. Some have freedom thrust upon them. Others simply surrender
Old 02-22-2004, 07:42 PM
  Pelican Parts Technical Article Directory    Reply With Quote #20 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 10:39 AM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2016 Pelican Parts - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.