what is the culprit here??

i can warm the car up to normal operating temperature, but neither fan turns on
i turn the AC on cold full blast, still neither fan turns on
the upper hose on the radiator gets hot
the lower hose on the radator going to the thermostat remains cold
the 2 relays in the ECM box next to the battery are ok
the fuses in the dash panel inside are ok

is it my engine coolant temperature sensor (ECTS)?? or what..?

help needed, thanks in advance

 

i checked my codes...not of much help, here is what i have:

P0440 (0705): EVAP system leak
P1448 (0309): EVAP canister vent control valve open

 

How old is the thermostat ??

-matt

 

AFAIK our thermostats fail open.

 

the car has 148k miles, I bought it last March, don't know if the thermostat has ever been changed.

According to Haynes, 3-3:
however, the upper radiator hose IS hot, it's the lower radiator hose that is cold

 

If the A/C compressor runs and your fans don't come on you have an electrical problem. Check the relays, the signals to the relays and the fan motors for proper operation. You can check the ECT sensor with an ohm meter. The Haynes shop manual has a resistance ~vs~ temp table for your referance.

Upper hose is the hot coolant from the engine. Lower hose is the cooled coolant flowing back to the engine. The whole cooling system must be throughly warmed up and flowing before the lower hose gets hot.

 

Have you got a blocked radiator? With cold radiator unplug lower hose and flush with water through top.. if flows freely its not blocked

 

t-stat or maybe faulty water pump. check cooling fan fuse/relay as well.

 

i could not figure it out, and neither can the mechanic so far after 2 days..he is tracing back thru the wiring to find the problem, but nothing so far..

any other suggestions??