Drivers side radiator fan only runs on high speed.
 

The driver's side rad fan does not run at low speed, but will run on high speed. Pass side goes on at around 102C according to the climate control diagnostic, but drivers side is off. When I run the AC, both go on.

Any idesas?

I have a similar situation - I'd posted a thread on this too and to be safe, I'm going to replace the driver side (passenger side for me as RHD - but same side as yours) series resistor. There was some debate on whether both fans were supposed to run at low speed when the a/c is off, but no definitive answer.

I've also asked a couple of independent mechanics and they weren't sure if it's normal or not.

When only one fan is on (a/c off or a/c on but compressor off ??), the temp can go up to 92-95 degree C (probably closer to the end of 0 on you 180 mark), technically not overheating yet, when both on, the temp is only about 82-85 C).

Is your temp similar ?

Please let me if you do get both your fans to come on at low speed with a/c off. My series resistor should be arriving sometime next month, so will only be installing it then. Will let u know if that changes things.

The low speed fan goes on at 103C, according to the climate control realtime diagnostic, and its supposed to go on at 97, so its switching on about 10F higher than it should. I'm not too worried since both fans run on high when the AC is on and here in Miami, I always have it on.

There are 4 relays that control the fans, I switched them all around (they are all the same) with no effect. I'm going to try to check the resistance of the fans at the DME connector, if the left varies significantly from the right, then I'm pretty sure the resistor is the fault.

Replaced the resistor and the problem is gone. also, claening the radiotors and condensers made a huge difference in loweing the coolant temp.