2003 jeep wrangler tj 2.4L my coolant fan won't come on. i replaced the coolant senser the relay and fuse still won't come on. i hot wire fan to the battery it comes on

the new code coming up now is 1491 the new code coming up now is 1491

ok, no a/c
sure unplugging the ect will cause the PCM to go nuts
it will go to limphome mode, and run rich.
best to not unplug sensors or risk burning the CAT up.

if the sensor ECT scans and reads same as reality, real water temp there is need to suspect any ECt. ever,unless aIR pocket there.

what temp? thermostat in car? that is first
and forgot to ask. 180 ,192,195,200f?
"P1491"quote:
Radiator Fan Control Relay Circuit
An open or shorted condition detected in the radiator fan control relay control circuit. This includes PWM solid state relays."
unquote.

if the PCM sends the fan on command
and the fan or relay is unplugged
this is normal.(for self caused errors)



what makes you think car overheats???
there are like 20 symptoms !
steam.?
dash gauge only told me this.?
leaks from odd places.?
pinging?
DTC error, overheated, is big time clue.
lost engine power?
the fan only turns on or TRUE overheat.
ONLY (lacking A/C)
215 is not overheated.most cars are 220f

the fan test to prove the fan works
we overheat it on purpose
all cars overheat, parked, all do
with zero air flow ,parked, passing through the radiator.
so it idles and idles, and finally the first rule is hit, in pcm, like 220F ,
and the pcm turns on the relay.
its that simple.



i make sure my thermostat is ok first
and read the stamp on it, 180f or 195f and
then see that the ECT matches that as engine warms,up, the scan tool shows ALL that.
live data.
you have real scan too there,not just a code reader?

S
if its real cold outside, like in alaska
the fan may never come on parked.
outdoor temps matter, .
when parked and idling in moderate weather.
the engine will overheat. and the
thermostat opens fully, and the fan
takes over... at 220f so.
sadly the SM does not show this secret number.
they have what is called.
Hysteresis
comes on at 220F (typ. example xj)
then off at 200f, this PCM programming
hard coded, rules. "unchangable"

let me teach you about EPA smog BS.
the EPA dictates changes HERE,
many cars now,180f is *******. by EPA
and is now near 200f,
the FSM for your jeep repeats the 180f mantra
over and over, for vast numbers of other non related DTCs,this tells me that its NOT 180f
see my logic?
it says, pxxxx dtc is not checked below 180f.
so its near 200f


see my drift?
that means the FAN on temp on all cars with 200f tamps will NEVER be near 200f or below.
above, 220f is common on vast newer EPA CARS
THE JEEP.COM
SHOWS STAT. p/n as.
53010552AC
BUT FAILS TO SHOW ITS TEMPERATURE
MORE PAIN.

if 1491 trips all things connected,its real
take that the bank.
(after reseting it of course)

if car only overheats (real) at stop signs
and fan is DEAD THEN
ect bad. or
air pocket on top of water jackets and ect.
or running pure water for coolent. omg.
or fan wire broken from pcm to relay
for sure 1491. that wire.
after all the relay and fan work hotwired.
dead last PCM bad. $$$$$$$$$$$$$$ ok, no a/c sure unplugging the ect will cause the PCM to go nuts it will go to limphome mode, and run rich. best to not unplug sensors or risk burning the CAT up. if the sensor ECT scans and reads same as reality, real water temp there is need to suspect any ECt. ever,unless aIR pocket there. what temp? thermostat in car? that is first and forgot to ask. 180 ,192,195,200f? "P1491"quote: Radiator Fan Control Relay Circuit An open or shorted condition detected in the radiator fan control relay control circuit. This includes PWM solid state relays." unquote. if the PCM sends the fan on command and the fan or relay is unplugged this is normal.(for self caused errors) what makes you think car overheats??? there are like 20 symptoms ! steam.? dash gauge only told me this.? leaks from odd places.? pinging? DTC error, overheated, is big time clue. lost engine power? the fan only turns on or TRUE overheat. ONLY (lacking A/C) 215 is not overheated.most cars are 220f the fan test to prove the fan works we overheat it on purpose all cars overheat, parked, all do with zero air flow ,parked, passing through the radiator. so it idles and idles, and finally the first rule is hit, in pcm, like 220F , and the pcm turns on the relay. its that simple. i make sure my thermostat is ok first and read the stamp on it, 180f or 195f and then see that the ECT matches that as engine warms,up, the scan tool shows ALL that. live data. you have real scan too there,not just a code reader? S if its real cold outside, like in alaska the fan may never come on parked. outdoor temps matter, . when parked and idling in moderate weather. the engine will overheat. and the thermostat opens fully, and the fan takes over... at 220f so. sadly the SM does not show this secret number. they have what is called. Hysteresis comes on at 220F (typ. example xj) then off at 200f, this PCM programming hard coded, rules. "unchangable" let me teach you about EPA smog BS. the EPA dictates changes HERE, many cars now,180f is *******. by EPA and is now near 200f, the FSM for your jeep repeats the 180f mantra over and over, for vast numbers of other non related DTCs,this tells me that its NOT 180f see my logic? it says, pxxxx dtc is not checked below 180f. so its near 200f see my drift? that means the FAN on temp on all cars with 200f tamps will NEVER be near 200f or below. above, 220f is common on vast newer EPA CARS THE JEEP.COM SHOWS STAT. p/n as. 53010552AC BUT FAILS TO SHOW ITS TEMPERATURE MORE PAIN. if 1491 trips all things connected,its real take that the bank. (after reseting it of course) if car only overheats (real) at stop signs and fan is DEAD THEN ect bad. or air pocket on top of water jackets and ect. or running pure water for coolent. omg. or fan wire broken from pcm to relay for sure 1491. that wire. after all the relay and fan work hotwired. dead last PCM bad. $$$$$$$$$$$$$$