cwlovell

Problem: '86 911 with blown heater blower motor.
Thought: Can I somehow use the footwell blowers without repairing the rear blower? I know the footwell blowers are wired in series with the engine compartment blower, but can I bypass the engine blower and still control the footwell blowers with the fan speed control between the seats?

I would like to somehow activate the foot well blowers without the engine blower operational. I do get some heat just from the engine shaft fan. I am thinking that with the footwell blowers working, maybe I don't even need the engine electric blower at all. Any thoughts would be welcome and thanks.

Bill Gregory

Without a rear air source pushing the air over the heat exchangers, I'm not sure the fans in front are strong enough to pull heated air by themselves. One option might be to adapt the pre-74 airflow from the fan housing directly to the heat exchanger air input duct at the bottom left corner of the engine compartment. You'd only do the left side on the Carrera. You can see a picture of what it looks like on my SC, look on the left side. There's an article on the tech.rennlist.com site that describes the change and the Porsche part numbers.

old_skul

I actually replaced mine at a cost of $253 (ouch!), but I had to have more heat. On the highway at 3000rpm I was getting sufficient heat but not enough.

Basically, you'd have to rig some sort of wiring switch for that blower - not sure how it's working. But honestly, at speed I got enough heat to defrost my windows and keep me from completely freezing through in sub-30-degree weather.

Stephen Masraum

It may be possible to jump a couple of connections in the 12 pin relay/module in the back to do it for you. I haven't tinkered with mine yet, but the thing's got connections for everything it seems like. If you don't have a Bentley or factory manual or the wiring schematics I could scan them for you and email them to you. Let me know.

cwlovell

I have thought through the options and heeded advice which says replace verses modify. Friends at Parts Heaven, Vertex, and Pelican have replacements for ~$200. I'm going for a replacement.
FYI, everyone(!) says stay away from used with the electic motor powered blowers unless you just love to keep fixing them.
Thanks everyone!