2005 GMC 1500 4wd 5.3 v8 Vortec.
GM Computer codes = B2425. We replaced the driver seat module, driver door module, driver heat
switch, driver whole seat swapped with a known good seat, body harness that goes to both driver and
passenger seat, passenger bottom cushion and back heater element, passenger heat switch.
Replaced seat heater circuit breaker by the brake pedal also reprogrammed driver seat module, driver
door module, pcm , bcm.
Question = I HAVE HAD A HEADACHE WITH THIS TRUCK ALREADY. I GOT A B2425 CODE WHICH IS
LEFT FRONT SEAT HEATER CIRCUIT. I CAN PUSH THE DRIVER SEAT HEATER AND SOMETIMES IT
WILL STAY ON FOR A LITTLE BIT AND SOMETIMES I CAN PUSH IT AND IT WILL TURN OFF RIGHT
BUT THE WEIRD THING IS I THINK THE PASSENGER SIDE WILL STAY ON ALL THE TIME TILL U HIT
THE DRIVER SIDE,,,AND THE OTHER WAY ALSO WHEN U HAVE THE DRIVER SIDE ON AN GO TO
PUSH THE PASSENGER SOMETIMES IT WILL KICK OFF...IS THERE ANY SUGGESTIONS U MIGHT
HELP ME OUT WITH??
Since you have replaced all these parts already, and i assume the modules programmed with the latest
software, then i think this bulletin may help...
Driver and passenger heated seats inoperative or shut off in 30 seconds. There will be DTCs B2435,
B2440, B3606 and/or B1825 set in the Drivers Seat Module. The adjustable pedal position sensor, seat
recliner position sensor and both heat seat thermistors share the same 5 volt reference internal to the
Drivers Seat Module. A fault in any of these components/circuits can make the heated seats inoperative
or shut off in 30 seconds, as well as, the seat recliner and/or adjustment pedals may move in short
increments when operated. A fault in heated seats, adjustable pedal or seat recliner will affect BOTH
Note:: Even if the vehicle is not equipped with adjustable pedals DTC B3606 still may set.
To help isolate the area of concern use the Tech 2 and go to "Sensor Data" in the Drivers Seat Module.
Monitor the following parameters for being out of range:
Recline Position- Normal range .39V-4.58V
Pedal Position (if equipped) - Normal range .39V-4.58V
Psgr. Seat Heat Sensor- Normal range 1V-4V
Drvr. Seat Heat Sensor- Normal range 1V-4V
If a parameter is found to be out of range inspect circuits for any opens, shorts to ground, or voltage. If
none found replace the suspect component.
Note: Please be aware of the following common areas of concern:
The adjustable pedal position sensor internally shorted pulling the 5 volt reference low.
Disconnect the adjustable pedal position sensor and see if the heated seats start
working correctly, if so replace.
Note Important:: The APP (Accelerator Pedal Position) sensor is NOT the adjustable
pedal position sensor. Make sure the correct sensor, adjustable pedal position sensor, is
The seat recliner position sensor internally shorted pulling the 5 volt reference low.
Disconnect the recliner position sensor and see if heated seats start working correctly, if
An open in either heated seat thermistor circuits (signal or low reference). The most
common is the passenger thermistor where it passes through seat connector C305 pin
"L" or "K" or C399 pins "R" or "G".
A chaff to ground on either heated seat thermistor signal circuits. The most common is
circuit 5475 black/red or dark blue shorted to ground in the passenger seat near the
Note Important:: The heated seat thermistors act differently to "OPENS and SHORTS"
than the adjustable pedal position sensor and seat recliner position sensor. The
adjustable pedals and seat recliner sensors can be disconnected for testing of the
heated seats. Where as the heated seat thermistor circuit must be working correctly
before EITHER heated seat will operate. Disconnecting one thermistor, which may have a
concern will not allow the opposite heated seat to work correctly, BOTH side must be
operational before EITHER heated seat will operate.
If DTCs will not clear when using the Tech 2 after a repair has been made, try operating
the device in which the repair was made. Example, if a repair was made to the passenger
heated seat thermistor circuit, the DTCs may not clear unless the passenger heated seat
GMC Sierra Heated Seats Shut Off