Gauges wont work when car first turned on, no driver display, heated seats turn off when gauges finally turn on, temperature control for front seats blows cold when set at or under 85 degrees. any ideas? is there a body control module?

Question edited for clarity.
Question moved from Spanish Car company 'Seat', pronounced See-At.

Check Fuse 13 (Heated Seats)

https://fuse-box.info/chevrolet/chevrolet-uplander-2005-2008-fuses-and-relay

..

Heated Seat System Operation
The driver and passenger heated seats have 2 heat zone operating modes with 3 heat level modes and will operate only while the engine is running. The heat zones are determined by which of the 2 heated seat buttons are pressed, while the heat level is determined by the number of times they are pressed. Pressing the seat cushion button 1 time will activate the seat back and cushion heater elements in the high mode. Each time the seat cushion button is pressed the seat back and cushion heat level is reduced from high to medium, low, and off. Pressing the heated seat back button 1 time will activate only the seat back heater element in the high mode. Each time the seat back button is pressed the seat back heat level is reduced from high to medium, low, and off. During heated seat operation the heat zone operating mode may be changed without affecting the current heat level mode.
The heated seat switches are momentary contact switches and are inputs to the driver and passenger door modules. Battery voltage is supplied to the switch assembly from the door module, and when a heated seat switch is pressed and released a brief switch signal voltage is supplied to the door module. Whenever the door module receives an active heated seat switch input, the next heated seat operating mode is determined by whatever the current mode may be. The seat heater elements are controlled by the driver seat module using inputs from the door modules through Class 2 serial data circuit messages. The driver seat module controls the voltage supply and the ground circuits to the seat heater elements. When a heated seat function is commanded active, the seat module will switch battery voltage to the heater element supply circuits, and ground is provided through low side drive control circuits. During heated seat operation both the seat back and cushion heater elements are supplied battery voltage. The seat module grounds the appropriate control circuits for back only or back and cushion heating modes, and opens or closes the active control circuits as necessary in order to maintain the desired seat temperature. The seat module relies on inputs from thermistors located in the driver and passenger seat backs to control heated seat temperatures. The thermistors are 2 wire sensors supplied with a 5-volt referenced signal circuit and a low reference circuit from the seat module. Resistance through the thermistors varies with temperature causing the heated seat sensor signal circuit voltage levels to decrease as the seat back temperatures rise. The seat modules allow heated seat operation only while the engine is running which is determined by a Class 2 serial data circuit message from the powertrain control module.

Heated Seat Components
The heated seat system consists of the following components:
• Driver and passenger heated seat switches
• Driver and passenger seat back heater elements
• Driver and passenger seat cushion heater elements
• Driver and passenger seat back temperature sensors
• Driver seat module
• Driver door module
• Passenger door module

Do you know what B - body DTC -diagnostic trouble code are ?
DTC B2425 Driver Seat Heater Circuit
DTC B2435 Driver Seat Back Heater Sensor Circuit
DTC B3941 Front Seat Heaters Circuit

Heated Seat Always On
Step
Action
Yes
No
Schematic Reference: Driver Seat Schematics and Passenger Seat Schematics
Connector End View Reference: Power Seat Connector End Views
1
Did you perform the Diagnostic System Check - Vehicle?
Go to Step 2
Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2
Operate the heated seat system.
Does the system operate normally?
Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems
Go to Step 3
3
Install a scan tool.
Display the Heated Seat Status parameter in the driver seat module Input/Output data list.
Start the engine.
Does the scan tool display the Heated Seat Status parameter as Off?
Go to Step 6
Go to Step 4
4
Display the Heated Seat Mode parameter in the door module Inputs data list.
Does the scan tool display the Heated Seat Mode parameter as OFF?
Go to Step 6
Go to Step 5
5
Turn OFF the ignition.
Disconnect the heated seat switch connector to the door module.
Start the engine.
Does the scan tool display the Heated Seat Mode parameter as OFF?
Go to Step 7
Go to Step 8
6
Replace the driver seat module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.
Is the repair complete?
Go to Step 9
--
7
Replace the heated seat switch. Refer to Front Seat Heater Switch Replacement .
Is the repair complete?
Go to Step 9
--
8
Replace the door module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.
Is the repair complete?
Go to Step 9
--
9
Operate the system in order to verify the repair.
Did you correct the condition?
System OK
Go to Step 3


your best bet , have a qualified repair shop diagnose the problem

The heated seats are a luxury feature that heat the front seats. This provides maximum comfort for the driver and the front passenger. To turn on the heated seats, press the heated seat button, which is a picture of a seat. There are two of these buttons, and each are located on the center console. The button on the driver's side of the console controls the heat for the driver's seat, while the button on the passenger's side of the center console controls the heat for the passenger's seat. Pressing the heated seat button will turn the heated-seats onto their highest setting. Pressing the button a second time will lower the heated seats to their medium setting. Pressing the button a third time will result in the lowest setting. Pressing the button a fourth time will turn off the heated seats. There are three lights next to the heated seat buttons to indicate what setting the heated seats are on.
Tip
The heated seats will only work when the engine is running.

I may b a fuse in the engine fuse box labeled gauges..check those and all other fuses pertaining to dash lights.. If they are good then it may be your wireing in the dash itself..or plugin wire to the dash may b faulty

Check out related help links with solutions to troubleshoot the problem:---
Click the link below:---
2004 Toyota Tundra: Oil Gauge and Temp Gauge Not Working?

http://howtobyme.blogspot.in/2012/05/2004-toyota-tundra-oil-gauge-and-temp.html

---------
Toyota 4Runner: Temperature Gauge Sensor http://technoanswers.blogspot.in/2012/04/toyota-4runner-temperature-gauge-sensor.html

-----------
Temperature gauge sits over half way mark? http://schematicsdiagram.blogspot.in/2012/04/temperature-gauge-sits-over-half-way.html
----------
Heater blows intermittently and temp gauge goes erratic?

http://technoanswers.blogspot.com/2012/01/heater-blows-intermittently-and-temp.html
------------- No heat on Oldsmobile Silhouette? http://technoanswers.blogspot.in/2012/02/no-heat-on-oldsmobile-silhouette.html
-------------
Temperature gauge does not move and no heat when heater is ON? http://technoanswers.blogspot.com/2012/01/temperature-gauge-does-not-move-and-no.html
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Temperature gauge keeps fluctuating up and down close to red? http://technoanswers.blogspot.com/2012/01/temperature-gauge-keeps-fluctuating-up.html
----------- Temperature gauge on the dash quit working on Pontiac Grand Prix? http://technoanswers.blogspot.com/2012/01/temperature-gauge-on-dash-quit-working.html
-----------
Dodge neon gauges not working? http://technoanswers.blogspot.in/2012/02/dodge-neon-gauges-not-working.html

---------
Heater blows cold? http://schematicsdiagram.blogspot.in/2012/02/heater-blows-cold.html

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Heat blows cold on drivers side and hot on passenger side? http://schematicsdiagram.blogspot.com/2011/12/heat-blows-cold-on-drivers-side-and-hot.html

-----------
1992 Lexus LS400: Engine overheats, Antifreeze out of reservoir and heater Blows Cold Air? http://whatisbyme.blogspot.in/2012/05/1992-lexus-ls400-engine-overheats.html

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These details will help.
Thanks.

You likely have a HVAC control head failure. The rear heater problem is likely a door actuator, the rear wiper is likely a open wire in the door jamb in the top. The gauges are likely a cluster failure.

check the fuses. they are under the back seat just pull up on the lower part of the back seat and it will come out. fuse box is on the drivers side. check to see if water is getting in that could be the cause.

chec the fuse box for bad then do an inspection of the wires for any corrosion/cuts--may hav a module thats bad or computer problem-get a tech that can do a mobile scan

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

• Heated seat elements
• Heated seat sensors
• Heated seat module (or memory heated seat module)
• Heated seat switches.

The heated seat system also relies upon resources shared with other electronic modules in the vehicle over the Programmable Communications Interface (PCI) data bus network. The PCI data bus network allows the sharing of sensor information. This helps to reduce wire harness complexity, internal controller hardware, and component sensor current loads. At the same time, this system provides increased reliability enhanced diagnostics, and allows the addition of many new feature capabilities. For diagnosis of these electronic modules or of the PCI data bus network, the use of a DRB scan tool and the proper Diagnostic Procedures are recommended.

The electronic modules that may affect heated seat system operation are as follows:

• Body Control Module (BCM) - Refer to Body Control Module in Electronic Control Modules for more information.
• Heated Seat Module (HSM) - Refer to Heated Seat Module in Electronic Control Modules for more information.
• Memory Heated Seat Module (MHSM) - If the vehicle is equipped with the Memory System, refer to Memory Seat Module in Electronic Control Modules for more information.

Refer to Power Seats Premium I/III in the Contents of Wiring Diagrams for complete circuit diagrams. Following are general descriptions of the major components in the heated seat system.

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

it sounds like you are getting a surge of voltage from your alternator/generator. Very strange.

the dealer can run a diagnostic test & pull fault codes or you can try this. If this helps, please report back & rate as fixya. Thanks. I am curious what you find as root cause. Good luck.

Instrument Cluster Self-Diagnostic Mode
To enter the instrument cluster self diagnostic mode with the engine off, depress and hold the odometer reset button. Turn the ignition switch to the RUN position and hold until the gauges sweep (within five to eight seconds). Depress the reset button once to advance to each stage of the self-test.
Turn the ignition to the OFF position to exit the instrument cluster self-diagnostic mode. If no DTCs related to the concern are retrieved, proceed to the Symptom Chart to continue diagnostics.


Instrument Cluster Self-Diagnostic Mode Odometer display Description GAGE Carries out gauge sweep of all gauges, then displays the present gauge values. Also carries out the check sum test on ROM and EEPROM. All segments illuminated. Illuminates all odometer segments. bulb Illuminates all micro-controlled lamps and LEDs. r #### Returns to normal operation of all micro-controlled lamps and LEDs and displays hexadecimal value for ROM level (used when requesting assistance from the hotline). nr#### Displays hexidecimal ROM level and type as stored in non-volatile memory (NVM). EE ## Displays hexadecimal value for EE level (used when requesting assistance from the hotline). dt #### Displays hexadecimal code for the final manufacturing date. ###C Gas engines display last temperature gauge input value from SCP, temperature gauge will indicate present temperature. Diesel engine displays present temperature analog/digital input in decimal as a ratio, temperature gauge will indicate present temperature. dtc #### Displays a 16 bit DTC in hexidecimal format. DTCs displayed are those detected in continuous operation not during self-test. EnG Displays English speed value being input, speedometer will indicate present speed. m Displays metric speed value being input, speedometer will indicate present speed. tAc Displays the tachometer value being input to the instrument cluster. Tachometer will indicate present rpm. FUEL Displays the present analog/digital fuel level being input to the instrument cluster as a ratio. OIL Displays the last analog/digital reading of the oil pressure switch contact resistance, oil gauge will indicate present level. br Displays the brake fluid level in an analog/digital ratio value. bAt ##.# Displays present battery analog/digital voltage. rhEo Displays present hexadecimal pulse width modulation (PWM) dimming input. rhi, rhS, rho Alternating 1 second display of pulse width modulation (PWM) input duty cycle, SCP hexidecimal dimming step, output driver counts in hexadecimal. Cr RUN/START sense circuit check. PA, Pb, PC, and Pd Displays 8-bit hexadecimal value for the Port A, B, C, and D readings (used when requesting information from the hotline). PE0-PE7 Displays 8-bit hexadecimal value for the Port E0-Port E7 in analog/digital readings