Question about 2002 Jeep Grand Cherokee
The heated seats doesn't work. No lights come on when I turn switch on for both sides. Can't find a fuse for it.
Jeep WJ !
you only have 2 choices
buy the fsm, or find it here. below or use alldata.com , it's all there.
or check all fuses.
each fuse has many loads. so test them all or read the FSM..
all cars. made.
lets see what is there. fuse 23 blown kills cruise. and brake lamps dead. or PCM in limphome and that can kill cruise,
is CEL out running? if not , CRUISE can be suspended for GOOD reasons, (safety) and more on newer cars...
now seats. not the power seat motors. but heaters.
both sides, dead, bottom and back side?
both sides, have a switch, that the BCM watches.
the BCM controls the seat heat.
above 105F ambient this system shuts down.
in the jeep dealer he connects the DRB and sees whats wrong fast.
if the switch LED are dead key on, the fuse is blown.
are yours? dead? (page 8g-5 , fsm)"heated systems"
if the fuses are good, and the lamp glows, at seat it will take
a dealer DRB tool to find true cause or all day with an ohm meter
per above heated systems pages.
here is how seat heat works, it not like a 1995 car.
the BCM watches that seat switch
it sees (monitors) what you do , then sends (by digital COMMAND via PCI bus to) SM.
power (12vdc) to the heater with the "SEAT MODULE"doing the heavy lifting (drivers)
THE SM drives the seat.
black org. wire to diver back heater. and white to bottom heater
so ill assume the SM lost power, (wild guess)
i can not find the fuse that runs SM module.
but if the LED is out, then the fuse is blown and gee, that is easy to find, just looking.
i dont have a searchable FSM, to scan for SM fuse.
Posted on Mar 25, 2014
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Posted on Jan 02, 2017
Sounds like the same problem I had. I brought it to the Jeep dealer and they told me that the heating element in the seat stopped working. They told me that the only way to repair was to take the seat apart and replace the heating element in the seat. Of course they will charge you the standard $80 to tell you this. and then quote you $500 plus to repair. I can't even remember how much, I have decided it was not worth it.
Also this website could help you:
Posted on Nov 03, 2008
Ok it is obvious since the light is coming on you are getting power to the switch. It could be a heated seat relay. Im fairly sure jeeps use a relay after the switch that is where I would start. Check and see if the Heated seat relay, and fuse are good
Posted on Dec 11, 2008
I will post it in 2 different posts because its too long DB
HEATED SEAT SYSTEM
Individually controlled driver and passenger side electrically heated front seats are available factoryinstalled optional equipment on this model, when it is also equipped with the power seat option. The heated seat system allows both the driver and the front seat passenger the option to select one of two seat heating ranges, Low or High, or to turn the individual seat heaters OFF using the heated seat switches located in the center lower bezel near the bottom of the instrument panel center stack. The heated seat switch circuit operates on ignition switched battery current supplied through a fuse in the junction block, only when the ignition switch is in the ON position.
The heated seat system consists of the following components
The electronic modules that may affect heated seat system operation are as follows:
The heated seat system will only operate when the ignition switch is in the ON position, and the surface temperature at the front seat heating element sensors is below the designed temperature set points of the system. The heated seat system will not operate in ambient temperatures greater than about 41 °C (105 °F) . The front seat heating elements and sensors are hard wired to the Heated Seat Module (HSM) or the Memory Heated Seat Module (MHSM).
The heated seat switches are hard wired to the Body Control Module (BCM). The BCM monitors the heated seat switch inputs, then sends heated seat switch status messages to the HSM or MHSM over the Programmable Communications Interface (PCI) data bus. The HSM or MHSM contains the control logic for the heated seat system. The HSM or MHSM responds to the heated seat switch status messages, ignition switch status messages, and the front seat heating element sensor inputs by controlling the output to the front seat heating elements through integral solid-state relays.
When a seat heater is turned ON, the sensor located on the seat cushion electric heater element provides the HSM or MHSM with an input indicating the surface temperature of the seat cushion. If the surface temperature input is below the temperature set point for the selected Low or High heated seat switch position, the HSM or MHSM energizes the integral solid-state relay, which supplies battery current to the heating elements in the seat cushion and back. When the sensor input indicates the correct temperature set point has been achieved, the HSM or MHSM de-energizes the solid-state relay. The HSM or MHSM will continue to cycle the solid-state relay as needed to maintain the temperature set point.
The HSM or MHSM and the seat heater elements operate on non-switched battery current supplied through the power seat circuit breaker in the junction block. However, the HSM or MHSM will automatically turn OFF the heating elements if it detects an open or short in the sensor circuit, a short or open in the heating element circuit causing an excessive current draw, or when the ignition switch is turned to the OFF position.
See the owner's manual in the vehicle glove box for more information on the features, use and operation of the heated seat system.
I WILL POST THE REST
Posted on Feb 03, 2009
contact your local dealer, all grand cherokee jeeps were recalled for faulty heated seat pads. they will replace them free of charge
hope this helps
Posted on Mar 03, 2010
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