Front condenser fan won't run
 

I am checking out the ac on my 82 911SC. The front condenser fan motor does not come on when the ac is running. The fan runs if I apply 12 VDC to it. Is there a temp switch somewhere?

I believe SC's have a relay for the front fan. Either on the fuse panel or in the smugglers box.

Here is the SC AC electrical diagram.

http://www.pelicanparts.com/911/911_Parts/Electrical/911_electrical_82SC_AC.jpg

I believe on my "84" there was no fuse so we put an "inline" fuse just where the power comes into the blower motor. Have you checked to be sure that you don't have an inline fuse? If you do it should be a 7.5A fuse. However your car might have a different schematic.

You can switch one of the relays just to be sure its not the relay which can be found on your fuse panel. For the exact relay just read on the backside of the cover for the correct location.

The fan only runs if the compressor clutch is engaged.

Mike,

West brings up a good point, I'm assuming that when you say, "the A/C is running" you mean the evap blower motor and the compressor clutch are both working? Are you getting cold air at the vent?

Mitch, yes, the a/c is running and blowing cold air. I will track down the relay. Thanks, everybody.

DAMMIT....!!

"...a/c is running and blowing cold air...."

That might mean only...A/C is "enabled" and blowing cold air...

Has someone VERIFIED that the A/C compressor clutch is engaged at the same time you're checking that the front blower is or is not running...?

Not being a hardaxx but it's hard to provide troubleshooting advice from afar without knowing/asking the explict circumstances.

I my expereince the front blower is a common failure item.

wwest, your statement that the fan only runs when the compressor clutch is engaged is quite clear. It is supported by the wiring diagram. So i would not expect the fan to run if the compressor clutch is not engaged. Thank you.

"...a/c is running.."

Sorry, but the above statement tells me NOTHING about/if the compressor itself is running. That's one of the reasons there is an aftermarket indicator light that can be used to "see" if the compressor clucth is engaged.

Of quite great value that indicator light can be.

Let's keep this on topic and friendly.

I'm interested about this too. I'm sure he's just looking for some help and not an argument. He'll check the compressor and get back to us.


Marky,

Let's start this off on a better foot. Welcome to Pelican! SmileWavy It's usually more friendly here. I'm sure you will find the help you need.

Hey WW,

Could the front condesor cause the fuse at panel to get so hot to melt and shrink? Only when I use stage 3 on the blower, it melt and causes a short in the system. Stage 1 2 are fine, it never gets hot enough to melt the fuse.

TIA,

Jim

Because I'm lazy, I would check for 12v at the connector. Could be a bad plug or whatnot. I know he says the blower runs with 12v applied, but I'd meter the input anyway.

Thanks Rusnak, Will do :D

Hi Draco, I did not see your post, brother. I was responding to #11.

I need to think about your question some more. I think there might be a loose connection on the fuse block, increasing resistance. That condensor blower uses a LOT of juice, and melts the fan switch quite regularly, and you can seriously burn yourself on the resistor pack in the footwell.

Thanks Brother, I've cleaned the heck out of the connectors at the fuse panel and insured a tight connection but when I turn the ac on the full "3" and put a infared thermometer, it gets freakin hot.

I will check the connectors at the components anyways to see which one is causing too much resistance. Process of elimination.

I did have my OEM Smugglers Box relay buzz like crazy, swapped with new and it stopped buzzing. did notice one of the wire look like it was melting prior to that.

Jim

Check it out asap before you use the AC again, see -

http://forums.pelicanparts.com/porsche-911-technical-forum/556486-fire-front-condenser-blower.html

Yeap, saw that, what a nightmare :eek;

Oops, correction: (argh) the EVAPORATOR fan is what I meant. That thing pulls a load, esp at high speed.

Yes, the relay powers the evap fan, and the resistor provides stepped voltage.

No Problem, will check it too :-D