Testing the Radiator / Engine Compartment Fans
 

Even with the higher temperatures that we have been seeing here lately, neither one of my front radiator fans have turned themselves on automatically. Similarly, I’ve never heard my engine compartment fan run, ever. Which leads me to wonder if these three (3) fans are even operational in the first place.

Of course, turning on the A/C does cause both front fans to come on, to what I assume to be their higher speed. So my interest now is in checking that, indeed, both front fans are capable of running at low speed – I’ve seen the stories about the blown-out electrical resistors associated with the lowest speed.

Seems like one ought to be able to just remove the relay for each fan, and then plug a temporary jumper wire between a pair of the relay pin sockets so to see if the fans are OK.

So, can someone who is more electrically clever than I am advise which pair of sockets at each relay location are to be bridged so to conduct this type of test? A picture / diagram is always a big help for such as this.

And, under what circumstances does the engine compartment fan click on? Does it operate in conjunction with, or independently of, the pair of front radiator fans?

Thanks - DM

The easiest way to test is with a Porsche specific scan tool, you can simply tell it to run.

When you turn on the AC, that turns the front fans on low, they turn on high if the engine coolant temp gets above a certain level or when the AC load meets a certain level. I don't have those levels handy but they are on this forum somewhere.

To test them without the durametric or other tools, you can jumper the relays and see if they come on.

I have a switch I configured to turn both fans on high on demand that I use when I am tracking the car, to help keep things a little cooler, especially on a cool down lap and driving in the paddock back to my parking.


Search for ben006 thread on radiator fans to find the steps for that, and it probably has links to the other info.

You can test all four radiator fan relays (2 high and 2 low) by jumpering the relays (if I recall correctly it's pins 87 & 30), or with a Durametric. You can find instructions and the relay location by doing a search. The engine compartment fan is triggered by the ECU based on several factors, you can also find this info by searching.

http://986forum.com/forums/diy-project-guides/60239-engine-compartment-fan-manual-switch.html

What Rick3000 said or go onto Pedros board for more detailed instructions

Got it!
 

Thanks for all of the comments / feedback. I'll poke around this weekend, and if any hiccups, will report back.

Thanks - DM

I just did this. removing the relays is a ********************. I needed pliers.

short jumper on 87 and 30 will tell you all you need to know.

fwiw, mine worked fine all the way around, but I wired a high speed fan switch to turn them on when I come off the track.