toplabels

Hi guys.....i have a 2001 996. My radiator cooling fans are acting up. This is what happens: The temp goes past the 180 mark, actually almost creeps up to the next mark (which does not have a number) between the 180 and the 250 mark. only after its almost to that mark the passenger side fan will come on high only. the driver side does not come on. while the temp is rising the low setting on either fan will not come on.

Yesterday with the help of a friend mechanic we determined the the ballast resistor on the driver side fan is bad. We are pretty certain it is so we ordered one and will change it as soon as we get it. Now the low side resistor on the passenger side is good but the fan will not come on on low as the temp starts to rise. Is it possible the driver side being bad affects the operation of the passenger side low speed function???

Still even though we think the relays are good the high does not come on on the drivers side when the passenger side goes on. I did do some searching yesterday and what i found is that they both should go on at the same time at low or high.

I also have a 997 and the 997 will turn both on at low or high at the same time which it seems only logical that it would.

Going back to the 996....hope i explained myself and did not confuse any of you.

Please help....track day next week need to get this resolved. at this point i would have taken the car to the dealer but not available in my city of el paso texas

logray

Did you check or try swapping the relays?

The mark between 180 and 250 is really very hot, you should not allow the car to get that hot under normal circumstances.

If you turn on your air con, do both low speed fans turn on? If they are working, they should be OK. The computer will activate them at the right temp.

You can test the high speed by removing the high speed relays (or maybe remove be low actually), the HS fans will click on and off every so often (but certainly put the relays back in when you are done).

Yes both fans should run at the same time, it's possible in addition to a bad ballast you have a bad fan motor, or wiring problem, but I would bet on a bad relay first.

toplabels

no we did not swap relays. we thought about that later once i was home from the shop. but i ordered one just in case. from what i have read if the high is not going on it must be a relay you are right.

low speed: thats the biggest question. we tested the low speed fan face by removing the relay which handles the low side and jumped them. the one on the driver side would not go on. the one on the passenger did go on. indicating that the resistor on the driver is bad and the resistor on the passenger is good. we also said if the driver side in not going on on low it also could be a bad fan but tested the fan directly and it does operate. So according to our testing the bad resistor is only on the driver side, but there is always a but, neither side will turn on on low????????

logray

If you turn on your A/C the low speed fans should come on regardless of coolant temp.

You can swap the high speed to low speed or L & R relays between each of the 4 fan relay positions, they are all the same relay IIRC.

If you already replaced the ballasts and tested the fan motors, then whats left in the equation are the relays and wiring.

afast16v

Hello there,
I have been having some issues with temperature as well, my 99 c2 temperature reading stays in the 180 mark, the needle normally tends to travel to the right side of the "0" I have turned the AC on and both fans come on.
Is it a normal operating temperature? Could something else be the culprit of higher temperature readings?
While I'm on the highway the temperature always stays right on the middle of the "0" of the 180 mark, it seems like low speed, street driving that makes it stay on the warm side.
I recently cleaned my radiators.
Thank you for your help.

logray

To the above poster, that sounds pretty normal to me and nothing to worry about.

Coolant needle straight up highway driving.

Not moving fast, street driving it will get hotter.

The right side of the 0 is nearing coolant temps of 100-105C and 110-115C oil temp. But that is still "within spec" so to speak. Should it run cooler, certainly can't hurt.

Your low and high speed fans should come on automatically once it reaches the appropriate temp.

afast16v

Logray, thanks for the fast response and the information

art c.

I just got into my wheel well(passenger), and found the ballast GONE. What do I need to order? There were 2 green and 1 white wires hanging.

logray

Depending on your model one of these:

99661610100 1998-2004 C2/C4
99662414100 2002-2004 C4S
99662414100 40th anniversary edition

street rod

What causes the rear deck lid fan to turn on? i have never seen mine come on.

logray

if it hasn't come on you aren't driving it hard enough.

engine compartment fan:

http://www.renntech.org/forums/topic...ost__p__176912

street rod

Thanks Logray. I ran it pretty hard the other day and it most likely came on but went back off during some calmer highway driving on the way back. Is there any way to know when it comes on other than going back there and looking?

logray

You could wire a simple 12v light into the fan circuit. Search for "fan hack" if you want to explore that.

Other than that, no there is not a way to tell.