Tip & How-To about 2004 GMC Envoy

Parasitic battery drain - likely source

Check the number 07 fuse under the rear passenger seat. It serves the Truck Body Controller 2 (TBC 2). The controller fails & is a known source of intermittent battery drain. The will not be blown, it is just serving a bad controller that is not turning things off as it should.

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2008 CTS drivers door switches don't work Just replaced battery All fuses are good

Did the switch work before replaced battery ? 2008 CTS ? Cadillac ? These switches are inputs to a control module , DDM - driver door module . a computer of sorts . A lot of thing's can go wrong with these systems , broken power or ground circuits inside the rubber boot from the body to the driver door . Communication problems between control modules etc... Plus the power windows don't use fuse's , has a circuit breaker for front windows - PWR/WNDW circuit breaker 25 amp located in the fuse box under the back seat , Fuse's are used for rear windows - two 15 amp fuse's LT/REAR an rear ,both are in the rear fuse box under back seat. These rear windows are controlled by the BCM - body control module .

The power windows system consists of the following components:
• Driver door module (DDM)--GMLAN device that receives and transmits messages and signals for window functionality. The DDM contains the driver door switch (DDS) which is integrated into the module. The DDS contains the driver, front passenger, RR and LR window and window lockout switches.
• Passenger front door module (PDM)--GMLAN device that receives and transmits messages and signals for window functionality. The PDM contains the front passenger door switch (PDS) which is integrated into the PDM. The PDS contains the front passenger window switch.
• Left rear power window switch--Provides switched voltage and ground window switch signals to the left rear window motor for left rear passenger window operation
• Right rear power window switch--Provides switched voltage and ground window switch signals to the right rear window motor for right passenger window operation
• Left front power window motor--Contains position sensors and a module that receives signals from the DDM and provides a status signal to the DDM
• Right front power window motor--Contains position sensors and a module that receives signals from the PDM and provides a status signal to the PDM
• Left rear power window motor--Contains position sensors and a module that receives signals from the left rear power window switch
• Right rear power window motor--Contains position sensors and a module that receives signals from the right rear power window switch
• DRIVER DR MOD fuse (15-amp)
• PDM fuse (15-amp)
• PWR WNDW Circuit Breaker (25-amp) -- front
• LT/REAR/WNDW fuse (15-amp) -- rear
• REAR/WNDW fuse (15-amp) -- rear


Power Window Operation
The driver and front passenger doors are equipped with power window motors that contains its own module. Each power window motor receives a hot at all times battery supply voltage and constant ground source. When the right front passenger window switch on the DDS is activated to the up or down position, the DDM will interpret the signal and send a GMLAN serial data message to the PDM. Upon receipt of the message, the PDM will send a signal to the front passenger window motor module on the GMLIN serial data circuit. The window motor module will then supply battery voltage and ground to the window motor to drive the window motor to the up or down position.
The DDM communicates via the GMLAN serial data circuit with the body control module (BCM) to control the rear window functions from the driver master window switch. The BCM is hard wired to each rear power window switch with circuits for window up, window down, and an enable circuit. The rear window switches contain internal logic that when supplied with voltage from the BCM over the enable circuit will driver the appropriate window in the direction commanded.
The rear power window switches are supplied with battery voltage from individual right and left WNDW fuses located in the rear fuse block. When a rear power window switch is activated to the DOWN position, voltage is applied to the motor down circuit and the motor up circuit serves as the path to ground. The window motor will drive in the downward direction until the switch is released or the window has fully opened. When the window switch is activated to the UP position, voltage is applied to the motor up circuit and the motor down circuit serves as the path to ground. Ground for the left rear power window switch is supplied at G200 and the right rear power window switch receives ground at G201.

The power locks work the same .

After replacing the driver door switch (DDS) or passenger door switch (PDS), perform the programing procedure.

If you don't know any of what i posted your best bet , have a qualified repair shop check it out .
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I have TBC WHAT THAT MEANS ON CHEVROLET SILVERADO 2000 4X4X 4.8L

Truck Body Control module aka Body control module..
things like locks,windows,wipers,etc on most new vehicles the switches you use don't go directly to the device they just send a signal to the module that sends it to the device telling it to do what it is supposed to do.
Hope that isn't as clear as mud.
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dome light fuse..??

The BCM - body control module controls those lights ! There are two fuse's in the rear fuse box that supply B+ voltage to the BCM for interior light's. TBC 3 an TBC 4. Fuse # 4 an #40 both are 10amp fuse's . Fuse Block - Rear
Beneath the left rear seat !
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99 chev blazer, service 4wd light is on. Simple things to check before the mechanic

There are a couple of fuses you will want to check. They are located in the under hood fuse box. The TBC ( truck body controller) and ATC (automatic transfer case) fuses.
If both are good, take the truck to your local Auto Zone and ask them to scan the vehicle for "trouble codes". Write the codes down and respond back.
Below is a diagram of the under hood fuse box and the fuse locations.

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What's on TBC 2B fuse?

incorrectly wired radio would cause problem.it would be the wire that is suppose to connect for dimming lights looks like a ground but is not has a yellow or a white stripe with black on it.use it as a ground and it will blow the fuse.
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