'Houston' we have a - Blower Motor Fire !

[Duckworth]

If you notice, the board seems to average a certain number of fires from electrical mishap relating to both the heater blower motor and the a/c front blower motor.

It would be wise to issue advance WARNINGS to folks about making some changes to the car before it happens to the next victim. Calling on folks to purchase the various fire-tec equipment is nice but....does not address prevention.

Why not just be rid of the heater blower motor ? ?
On my SC I had ALL the heat I needed and then some - even with it's removal. Some people told me that I was building heat up in my exchangers and warned against doing this. Last time I checked the exchangers were steel and they didn't concern me all that much.... Fire concerns me.

A 911 is designed to give you heat when you raise the RPM in my opinion and it does it better than I expected. So what's up with adding an extra electrical 'gremlin' that sits there waiting to strike ?


Phil
_________

'74 fiat 128
'80 928
'82 Targa - sold

[Craig 930 RS]

Is this SOB fused?

[Kenny Fignewton]

Phil,
I agree. My blower was shot, so I removed it. I still have plenty of heat.
The blower is fused by the block just under the CDI on the left side of the engine.

[Brian 162]

When I bought my car I didn't know there was a blower motor because there wasn't one. (Thats why you need someone you trust to inspect the car. I bought mine from my ex-mechanic and got scrooooood). Anyway, for heat I have a hose that goes from the fan assembly to the heat exchanger. The set up seems to work. I have tons of heat.

[Duckworth]

Without scaring folks too much wouldn't it be a benefit to have a link

such as .........................'FIRE - Causes of it in 911's'

This presumably would give out tips and procedures to get owners involved in sorting out their cars to vastly reduce the chances of what must be, a horrendous experience.

Granted that MFI is a different set of variables to an SC or later, but the link could address them as: early 356 fires / MFI fires / CIS fires / Motronic fires etc.

[ianc]

Why not just be rid of the heater blower motor ? ?

I'll tell you why. The engine fan does well at putting air through the heat exchangers at speed, so if you never get stuck in traffic jams and don't spend any time in traffic, then you don't have a problem.

If, OTOH, you live in a populated area, you absolutely MUST HAVE the blower motor to defrost your windshield in the rain and cold unless you constantly want to be swabbing your windshield with a towel to clear it.

There is no reason why a blower motor should cause a fire if it and its attendant wiring are in good condition. Your responsibility.

New blower motors are pricey, but you can easily fit a much cheaper motor instead. See here: Carrera replacement heater blower (long)

ianc

[Decolliber]

As others have asked, why would it cause a fire if it is fused? It is one of the 3 fuses on the left side of engine compartment, under the cover.
The blower that is really dangerous is the front a/c condensor blower - it does not come with a fuse and you need to add one (7.5 amp).
I also added a fuse to the fresh air blower, as the original one had melted into a big blob inside.

[Duckworth]

If, OTOH, you live in a populated area, you absolutely MUST HAVE the blower motor to defrost your windshield in the rain and cold unless you constantly want to be swabbing your windshield with a towel to clear it. ... Ianc

But something just does not add up for a setup to run the blower non-stop. This somehow seems to have been a haphazard idea - for the following reason:

For the occasional rainy day with lots of idling, a toggle switch to activate the fan for the 10 - 30 minutes necessary followed by shutdown [just like your wipers] makes for a more logical way to use the blower.

...Unless, there is perceived benefit to keeping a small, but steady flow of air thru the heat exchangers to offset higher temps inside of them. But as they are steel - why bother ?

Phil
__________

'74 fiat 128
'80 928
'82 Targa - sold

[ianc]

But something just does not add up for a setup to run the blower non-stop.

A couple of points:

It sounds like you're confusing the footwell blowers with the main blower fan. Do you have an SC or a Carrera? None of these blowers run non stop unless the levers between the seats are pulled up with manual heat. The Carrera footwell blowers run (on manual heat cars) even if the switch on the center console is in the '0' position, so that may be what you're talking about, but you don't give enough info to say. Do a little more research on this for your year car.

there is perceived benefit to keeping a small, but steady flow of air thru the heat exchangers to offset higher temps inside of them.

There is. Carreras even have a circuiit activated by a temp sensor in the case breather to turn on the blower fans after the ignition is off, if the temp is too high. Blowing air through the heat exchangers has a beneficial effect on engine cooling, and it happens all the time, but it's only diverted to the cabin when the flapper valves are open.

ianc

[ChemMan]

I just bought a new blower motor of ebay for $76 with shipping. Just the motor not the housing etc. If any of you are ooking, do a search on ebay. There was one left.
Mike

[Wil Ferch]

Want to list sources of possible electrical fires???

See what I say to Glascow...here --->

Dash lighting fuse installation

- Wil

[Duckworth]

Blowing air through the heat exchangers has a beneficial effect on engine cooling, and it happens all the time, but it's only diverted to the cabin when the flapper valves are open. ...Ianc

Somewhat at a loss to see what additional benefit there is to be had cooling the engine with that small rear blower. Has this been confirmed as a benefit in heat of summer driving ? I've always felt that claim rang hollow - but am open to the argument.

You may be right about when and how the rear blower should operate - the main blower isn't an issue so far. But in the case of my SC this pesky thing ran 90% of the time regardless of my settings and later quit altogether. A HUGE relief to me when I put it in the trash.

As far as "having a circuiit activated by a temp sensor in the case breather to turn on the blower fans after the ignition is off - if the temp is too high" - it's sounds like an invitation to serious trouble to me. Porsche people are CONTROL- freaks and I don't like relinquishing control to these type of electrical- sensors. Even if there is a small benefit - keeping the simplicity to the car in my book means removal of items that will only bring trouble down the road.

When I achieve this after working on a car I find myself 'elated' with the new result and new reliability...I'll bet you do too.

Phil
_________

'74 fiat 128
'80 928
'82 Targa - sold

[ianc]

I don't like relinquishing control to these type of electrical- sensors. Even if there is a small benefit - keeping the simplicity to the car in my book means removal of items that will only bring trouble down the road.

You'll be driving a pan, four wheels and an engine before long with that kind of philosophy. Better to repair things properly that aren't working than ditch them altogether to my way of thinking. Doing so makes me feel 'elated'. In some cases the factory design can and should be improved upon, and that's a plus as well.

ianc