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Bit of info required about the 996 fans......

ScoobyDoo555

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Joined
26 Feb 2012
Messages
1,414
Hi All,

Noticed a couple of things recently that I need to get sorted. Car has been off the road for most of the Summer (!) whilst holidays and teaching my daughter to drive have taken over.

Some background first.
So I noticed 2 things:

1. AC not working - checked the front and it appears a condenser has failed (tell tale signs of leakage from a stone strike)

This has led to the system shutting down as all the gas has leaked out.
So, I've got a replacement and will refit today.(no legal issue as there is no gas 😂)
I can then get it pressure tested and refilled this week.

This may have affected my other issue -

2. noticed that the car (that has a LTT fitted, so should sit solidly on 80 degrees), crept up in standing traffic when I drove it last week. I noted that the driver's side fan hadn't kicked in.

Looking down, the ballast resistor looked like it had seen better days, so I've already soldered on a replacement working resistor.

But there's no change in temps nor high speed fan kicking in.

As plan b, I've got a spare fan assembly (whole thing) so I can change that too whilst the bumper is off and I'm changing the AC.

HOWEVER, my question is regarding the fans - will the temporarily "non-operational" AC affect my fans operation for say, cooling the car?

Will I need to get the system working to gain high speed fan operation?

Car isn't being driven at the moment, so time isn't an issue. Just want to get it sorted.

Thanks in advance,

Dan
 
The fans ran on mine at low speed when AC was not working. High speed operation is controlled by the ECU but I have never seen mine come on. Both fans should come on with AC. Easy to tell by listening or putting your hand over the air outlet.
The temperature on mine creaps up in traffic too, even with new radiators and two working fans.

MC
 
Thanks buddy.

As confirmed - AC rads are fubar'd. The nearside one was worse than the offside - expected as the one is closer to the dirty side of the road.

I did them 4 years ago and they've been cleaned relatively regularly. TBH, there wasn't much crud due to the mesh I installed. (so nice to see that's worked well).

The whole thing is easy to do, but just not complete as I need to now order another condenser and o-rings.

Did panic when I heard a hissing sound as I undid the fubar'd condenser..... until I realised it was the cushion I was sat on!!!! :floor: :floor: :floor: :floor: :floor: :floor:


Still need to get to the bottom of this fan issue, as I simply don't recall it ever getting warm in traffic as the ac would be on. Hence my "awooga" now it's not working.

Dan
 

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You need to access the true temperature of what's going on here and not what your gauge is showing. Seeing as yours is a 3.4 Dan, you can interrogate the ECU live digital information on your climate control display. Turn it on to read the true water temp. Watch the level rise until the trigger point for enabling the fans is reached. Then see what your fans are doing. AS a quick check on the fan operation, I connect a 2v battery charger straight to the fan wires and see if it runs.

Read here to see how to read the live data:

http://911uk.com/viewtopic.php?t=81945
 
Cheers Alex,

I did recall there being a more accurate method of checking (had an Audi S4), but tbh, I want to get these bits on the car first (sort one problem at a time and see how it) - anything blatantly wrong needs correcting before diagnosing any other problems (especially if they may be related)

Will have a play with the panel when I get these parts sorted - got a bit of a deal with ECP this weekend - picking them up on Tuesday :thumb:

Dan
 
A/C on and even with no gass in the system the fans will still run at slow speed .

If one side is not working and you have changed the resistor then it could be a relay or the fan has died .

Need to get the coolant to 105 degrees for the fans to kick in on high speed ( seperate relay to the low speed ) as this will prove if its a fan or a wiring fault .

Ive read on here not long ago about someone changing his waterpump which had NOT failed and finding the temp was much lower .. sounds very similar to yours although it would appear you have x1 fan inop and that would affect it :)
 
Thanks Demort,

TBH, I was leaning towards the fan being borked anyway. As it turns out, I've got some other things to do as well now :D

The fan does look like a bit of a pig to change, so thankfully I can try to do the ac rad change during the week, leaving the fan for the weekend (may as well change it as I've got the part).

Dan :thumb:
 
Fit some mesh over the air intakes to stop damage to your new condensers!
 
Scobby,

Off-topic, you note at the foot of your posts your running 997 C2S brake discs? - Or have I miss read this?

If this is the case could you provide more detail please :thumb:
 
I have a similar issue, Drivers side fan works High speed, passenger side fan seems to be on low speed (air con on max setting). Think it must be the relay. Which relay is it?? There are 5 relays under the foot well area.
 
Yas.SYC4S said:
I have a similar issue, Drivers side fan works High speed, passenger side fan seems to be on low speed (air con on max setting). Think it must be the relay. Which relay is it?? There are 5 relays under the foot well area.

Relay board 1 above the fuse box , positions 20 and 22 .. not sure which side is which .
 

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Thanks Demort! Will order my new relays.. easy fix!
 
Yas.SYC4S said:
Thanks Demort! Will order my new relays.. easy fix!

A quicker check would be to swop the relays , if the fault swops side to side then ok its a relay .. if not then its out with the meter and ill post a wiring diagram .. i like wiring faults :D
 
Before going to the relays I would check for volts at the resistor. You can activate the high speed fans by heating up the engine bay sensor which sits in a slot in the top of the inlet manifold. When removed it can be a pig to put back until you find the right technique. When that is active you should have battery voltage on the fan side of the resistor. When only the AC is on you should have battery voltage on the other side of the resistor and a lower voltage at the fan.

MC
 

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