why my fans not coming on on my Lexus ES 300 2002

Your fans are connected to a coolent temperature sensor that tells the fans when to come on . The sensor is some were on the engine block. Do not know exactly were on that vehicle. May went to check with your nearest parts store and ask can you see the repair manual for your vehicle. Sometimes they are nice and will let you look at the manual with out purchasing it.

you need a test light or a jumper wire. you need to bypass all the crap and just put 12v to the fans and test them. rule bad fans out. check fuses. check wiring for bare wires and shorts. coolant sensor should be around the thermostat housing somewhere...intake where water flows...should be easy to spot.

is it actually overheating?

http://www.clublexus.com/forums/