cooling fans
 

Hi , Does anyone know if both front Fans should run at low speed with only engine running ? I have a 1999 Boxster and I only hear the left low speed fan running . If I turn A/c on both fans run at high speed. Please help !!

The are controlled separately but should come on together at low speed... and if the AC is on they will both run on high that is correct.

If you're wondering if they are working right, you can do two tests.... 1.) See if you can get access to a Durametric and run a quick fan test on each... or 2.) you can look at the Relay panel over the fuse panel up in the driver side foot well. The fan relays are in the lower row right side relays (4) - Check the relay chart... from right to left is: right/high - right/low - left/high - left/low. A manual test can be run on each bridging sockets 87 and 30 on the panel side with a short jumper wire.... if the fan doesn't work on one of the low speed relays then likely one of the resistor packs on the fan units up front (each fan has one).

Heiko

Both fans should run at low speed with the AC on. If only one runs at low speed and they both run at high speed, then most likely you need to replace the ballast resistor on the side that doesn't run at low speed. Of course, it could be the low speed relay. Just switch the two low speed relays and see if the fan on the bad side starts running again at low speed with the AC on.