Lexus RX AC fan not turning on.

[Kurtatron]

I noticed the AC wasn’t cooling at idle. The fan isn’t turning on. I’m trying to figure out if the fan is the issue or something else.

I’m only getting about 10 volts at the connectors to the fan. Is that too low?

I saw the temperature gauge increase from below halfway for the first time since buying the car. It was at a stop sign with the AC on. I don’t know how to test the radiator fan voltage because it isn’t turning on.

Voltage at the battery is 13.49 at idle.

Edit: I ran the car at idle and revved it for a while. Both fans are only getting about 10.1 volts at idle.

When I revved the engine, the radiator fan turned on. Let go of throttle, it turned off. Like clockwork. They turn on and off with engine rpm. What could be causing this? Alternator seems good to me.

 

[charbaby]

https://www.clublexus.com/forums/rx-2nd-gen-2004-2009/643734-a-c-condenser-fan-issues.html

 

[Kurtatron]

turns out my diagnosis was correct. Swapped out the radiator cooling computer that’s fixed to the radiator shroud. Put in one from a Sienna, which is cross compatible.

I suspected it was the computer because 10.1 volts seemed low at idle. And when I revved the engine, the fans would come on.

I turned on the AC and the fan turned on at idle. New computer fixed it.

Just posting here for future reference for other older sienna and rx330 owners.