Hello all, I haven't been on Rennlist since I sold my 951 (hence my user name), but have finally made the jump to 911 heaven! Anyway, recently purchased a 2005 997 base Carrera 3.6 in the Toronto area and had a PPI done by Gtek. Car passed with flying colours. The car has 112,000 kms and had the IMS and RMS along with the clutch & pressure plate, flywheel and release bearing replaced at around 100,000 km (at Mark Motors Porsche dealer in Ottawa with all Porsche parts). Car is running great, but with this warm weather I have gotten the warning for "Engine Compartment Blower." I did some searches and checked the fuses. There was only one fuse there and it was already 15 amps and it was not blown. With the fuse pulled and the car running I only get 10.2 volts at the tabs where the fuse plugs into, which leads me to believe it could be a relay. Unfortunately, that whole fuse/relay block is not numbered or labeled so I don't know which relay is which. Also, I took the wiring connector off the blower motor itself and ohmed out the fan, It shows 0.0 ohms. I'm sure this isn't correct as all wound electrical motors show some resistance. It's not "open" (as in no reading or infinity) it just shows 0 ohms. Looks like I need a fan too, but I would probably replace the relays anyway just to sure.

Does anyone have a wiring diagram for that or perhaps know which relays are for the engine blower? I assume there are two, for high/low speed although there is only one fuse. Also, best place to buy new fan motor? Any and all help would be greatly appreciated.

 

If you put 12v directly to the fan, does it run?

 

Thanks for responding, Petza914. That's my next move. I just moved and gave away a lot of excess things...like spools of wire I hadn't used in a long time! So, off to buy some wire.

 

Checked the fan by running some wire to another battery and it works perfectly and doesn't have any bearing noise,

I assume the purple ones are the high/low relays.
so the fan is fine. The engine bay temp sensor is sitting nicely in it's rubber grommet in the engine bay and the fuse is fine so it must be the relay or relays. I just don't know which relay is the fan relay.

 

Update: I figured out which relay belongs to the engine compartment fan and the purple relay on the far right top is #7 - the low speed relay, and the purple one next to it is #8 - the high speed relay.
I checked them with my meter and they seem to be fine, but I replaced them anyway. I also replaced the 15 amp fuse although the old one was not blown. Fan still does not come on.

I then pulled the engine bay temp sensor and tested it at ambient temp., with the tip immersed in cold water and also hot water. Resistance readings were 2K ohms at ambient, 4.2K ohms with the cold water (40 deg F), 0.4K ohms in hot water (176 deg F). So the sensor seems to be working correctly.

When I turn the key to on I get approx. 11 volts at the 15 amp fuse then it soon drops to approx. 2 volts. Not sure why it does this. I can't check the voltage on the fan connector because when the rear lid is open the fan will not run. Which leads me to my next question:

Could the switch in the engine lid latch be defective? The engine bay light comes on when the lid is opened (not sure if this is linked).

Does anyone have a schematic that shows what feeds the 15 amp fuse? I would love to get the fan working. Thanks in advance.

 

The fan will not run with the engine lid up, as you've discovered. That's by design for safety. I believe I'd that switch was bad though, you'd get a warning for engine lid not closed when you tried to drive that way.

 

Thanks Petza914, that makes sense. I guess maybe check for a short in the wires because I know the fan works. Sure would be nice to have a wiring diagram.

 

I too am receiving this message on my "New" 2008 C4S. Any update?

 

any update on this?

I found a diagram I used a while ago. It has the blower wiring on there but not much help. You could at least test the wiring from the harness to the blower to rule that out.