Footwell Blower wiring in SC

DCred911SC · 03-12-2009, 02:05 PM

Looking to wire up the footwell blowers I've installed in my 82SC. I still have the engine compartment fan, but I was wondering whether I could use the same 25amp fuse to supply power to the footwells aswell (through separate relay though). Would the 3 fans running provide too much current draw and blow the fuse ?

I've got the carrera resistor pack to control the speeds, and plan to install separate relay and power for the high speed position.

Any comments welcome

Thanks
David

LM3929 · 03-12-2009, 02:52 PM

David

I'm looking to do this to my 83 SC as well.

Why not use a feed wire off of the frt, blower switch to the Carrera relay and switch

where did you find the Carrera harness?

Lorne M.

Mysterytrain · 03-12-2009, 04:16 PM

I did this a couple of years ago.
How to Install footwell blowers in pre -84 911's

DCred911SC · 03-13-2009, 05:34 AM

Ron,

I know you did lots of research during your install, do you see any issues running the 3 fans from the same supply, maybe even using the same existing relay to switch and power all 3 (except the high speed position) ?

Thanks

David

Mysterytrain · 03-13-2009, 06:34 AM

David,
Its been a while since I got deep into the ying-yang of the wiring. Porsche began to fuse the individual footwell blowers with 10 amp fuses. Based on those numbers you would need a relay rated at 30 amps to run all three blowers. I'm not sure what the rear blower relay is rated at but it is only fused with a 25 amp fuse so you might be over the limit. Remember the big current draw would occur at turn on. I really think you would be more then happy with just the 2 footwell blowers. In my opinion the rear blower has always been useless and removal makes for a nice clean engine bay.
With my install I made things more difficult for myself because I wanted to slow down the high speed position [ too damn much noise] and have a very slow default low speed to spin the blowers when the fan control was in the off position. Basically, I gave myself four speeds.
If you base your install on the factory setup and use the ceramic resistor pack and the aux relay for the high speed setting it will be much easier. My 100 watt power resistor pack was over kill, but it does work well. The worst part of the install was when I decided to go from the original 3 speed setup to the 4 speed with a center console. Installing the console, the new E-brake and the additional wiring was a huge pain. The upside is it looks factory and I can bake bread or slowly BBQ ribs in the footwells.

Joe Bob · Joe Bob's Garage

What is the CFM rating on the blowers?