Porsche Enthusiasts Club Forum

Hi all

My cooling fans are running continuously when the ignition is switched on. I beleive this points to a faulty relay.

I think the part is about £180 brand new.
Part number is 944-615-104-03.

Does anyone have a working spare I could purchase or do I have to bite the big one!

cheers

Mark

unplug the temp sensor in the rad just below the top hose, if the fans stop thats your problem,

about £20 from ebay fits in a few cars other than porsche

I thought if the fan runs continuously with ignition on the fault lies with the relay and if the fan run continuously with no key in the thermostatic radiator switch is the culprit.
Mine is running continuously with ignition on.

Could be the relay, but when the guys at work told me my fans were still running an hour after I arrived the other day it was the temp sensor switch on the radiator. Bugger to get at from above and far easier if you can get at it from underneath after dropping the tray. Much less expensive than a new relay too

http://www.ebay.co.uk/itm/Radiator-Temp ... 235338aa67

thats the three pin version

http://www.ebay.co.uk/itm/NEW-Radiator- ... 2a52078420

Two Pin

Thanks guys,

I fitted a new two pin one of these three months ago, two pin from 9apart.

The fans when the switch failed as suggested ran on an totally flattened my battery.

The fans yesterday were running when I keyed into the ignition.

I put the key in last night later on and no problems Used the car fine this morning all appears fine. I will have to monitor it closely.

Mark

Hi Mark -

What temp does the dial read at? How's the coolant level? Have you checked the header tank cap for perishing? Is your thermostat stuck (ie not delivering warm air to cabin)?

It may seem odd questions but worth looking at each. I replaced my header tank cap a while back as it was in fact perished (that cured the overheating). A short while later I replaced the standard thermo and the rad switch at the same time to the Porsche 'hot climate' system configuration (that's another subject...)

Having said all that, your fans should run for a couple of minutes after ignition switching off, depending on any 'latent heat' build up and the ambient temperature - I think your problem is the temp switch in the rad - relays don't normally fail...

Dave
Cape Town SA

Hi Mark -

I have just remembered another thing - do you have A/C in your car? If so, and the A/C button is ON, your fans will run continually until you switch the A/C OFF...

Dave

Coolant level fine, expansion tank cap recently replaced, warm air delivered the the cab non air con car.

No overheating observed.

Thermo rad switch replaced 3 months ago, the car seems to have cured itself.

Running perfect at the moment.

Will keep a close eye on it.


Thanks for all the replies.

Mark

What brand of switch did you get? I know an LR switch has been advised on here, but on my BL cars I have had no end of issues over the years with dodgy sensors.

Mine was a facet - seems OK one month on......

On my Stag I had a plethora of issues with sensors made by Lucas, Facet and some random Chinese branda (if you ask me, they were all the same).

The first one would go from the middle of the gauge to red within a 5 degree range (85-90) - great if you are stuck in traffic.
The second one went to near the red in comparison to the first.
The third one? Worse than the first and that was under warranty!

I bled the system, and even bought an IR meter to read the temps in various areas. I will not even go down the route of how many voltage stabilisers I tested... In the end I did what I did with my MGB ; Spent £70 on a mechanical gauge. Some peeps said electrical would be more accurate (I found that laughable from my findings above). With the Smiths capillary gauge I found out that my overheating woes were over nothing. Just as well on a car which has a large reputation for boiling over.

What's annoying is that I probably spent £30-50 in pissing about, not to mention time