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Have a scan tool ? Factory or some other professional type scan tool . Not a code reader ,code reader will not view BCM - body control module codes or switch input data . Plus you would need to know how it all works . Ignition switch is a low voltage input to the BCM . Depending on switch position , ACC / RUN / START etc... the BCM will set the power mode for the vehicle by energizing relay's an sending serial data messages over the GMLAN high speed serial data network to different control modules - PCM - powertrain control module . The BCM on your vehicle is what GM calls the PMM - power mode master .
The body control system consists of the body control module (BCM), communications, and various input and outputs. Some inputs, outputs and messages require other modules to interact with the BCM. The BCM also has discrete input and output terminals to control the vehicle body functions. The BCM is wired to the GMLAN High speed serial data buss and the GMLAN Low speed serial data buss and acts as a gateway between them. If the BCM does not communicate the vehicle will not start due to the inability of the engine/powertrain control module (ECM/PCM) and vehicle theft deterrent (VTD) control module to communicate without the BCM providing the gateway function.
Power Mode Master
This vehicles BCM functions as the power mode master (PMM). The ignition switch is a low current switch with multiple discrete ignition switch signals to the PMM for determination the power mode that will be sent over the serial data circuits to the other modules that need this information, and so the PMM will activate relays and other direct outputs of the PMM as needed. Refer to Power Mode Description and Operation for a complete description of power mode functions.
Serial Data Gateway
The BCM in this vehicle functions as a gateway or translator. The purpose of the gateway is to translate serial data messages between the GMLAN high speed buss and the GMLAN low speed buss for communication between the various modules. The gateway will interact with each network according to that network's transmission protocol.
One example of this necessary communication is the communication between the engine/powertrain control module (ECM/PCM) which is high speed serial data and vehicle theft deterrent (VTD) control module which is low speed serial data. If these modules can not exchange information, the vehicle will not start.
Communication between the BCM and a scan tool can be on the high speed GMLAN network or low speed GMLAN network. If one network is lost, the BCM can still communicate with the scan tool. A lost communication DTC typically is set in modules other than the module with a communication failure.
Serial Data Power Mode Master
Power to many of this vehicles circuits is controlled by the module that is designated the power mode master (PMM). This vehicles PMM is the body control module (BCM). The ignition switch is a low current switch with multiple discrete ignition switch signals to the PMM for determination of the power mode that will be sent over the serial data circuits to the other modules that need this information. The PMM will also activate relays and other direct outputs of the PMM as needed. The PMM determines which power mode (Off, Accessory, Run, Crank Request) is required, and reports this information to other modules via serial data. Modules which have switched voltage inputs may operate in a default mode if the PMM serial data message does not match what the individual module can see from its own connections.
Circuit Description
When the ignition switch is placed in the Start position, a discrete 12-volt signal is supplied to the body control module (BCM) notifying it that the ignition is in the Start position. The BCM then sends a message to the engine control module (ECM) notifying it that CRANK has been requested. The ECM verifies that the transmission is in Park or Neutral. If it is, the ECM then supplies 12 volts to the control circuit of the crank relay. When this occurs, battery positive voltage is supplied through the switch side of the crank relay to the S terminal of the starter solenoid.
What make , model an year vehicle ? It's probably that the speedo gauge is bad . If the vehicle has no problem shifting the VSS - vehicle speed sensor is good . Some vehicles get speed information from ABS wheel speed sensor . GM had bad step motors in side the instrument cluster , these are what control the gauges ! Also most vehicles VSS - info is a input to the PCM - engine computer , the PCM shears this info on the serial data network . How to Diagnose Controller Area Network CAN
The odometer will display 'error' if an internal IPC memory failure is detected or if there is a serial data communication fault between the ECM and the BCM. IPC instrument panel cluster .
Circuit Description
The communication among control modules is performed through the GMLAN high speed serial data circuit and the GMLAN low speed serial data circuit. The modules that need real time communication are attached to the high speed GMLAN network. The body control module (BCM) is the gateway between the networks. The purpose of the gateway is to translate serial data messages between the GMLAN high speed buss and the GMLAN low speed buss. The gateway will interact with each network according to that network's transmission protocol. Refer to Body Control System Description and Operation for more information about the gateway.
Your best bet is to take your vehicle to the dealer , sorry !
What make , model an year vehicle ? your gauge is probably bad ! The vehicle speed sensor is an input to the PCM / ECM - engine computer . All vehicles after 1996 have some kind of a serial data communication network that all modules talk on ,even the instrument cluster ! The PCM sends speed info . to the instrument cluster . Google automotive serial data bus communication network . GM had problems with the stepper motor in their clusters , but so have other car makes . If you would have taken it to a ASE certified repair shop you would wasted your money on a VSS - vehicle speed senor you didn't need .
Sorry for the late reply. Some 3-speed switches are as easy to replace as giving me the model number and serial number of the fan and plugging a new one in. In most cases though, we ask the customer to write down the color code (which colored wires go where in the switch) then I have to break open the switch to identify it. Since I field phone calls from all over the US and Canada, I ask the customer to mail me the switch. You can reach me toll-free at 1-866-600-3267.
Seems that your Pure-Fi Elite had the same problem as mine...sorry for that, but this model does not have a "mute" function. If you bought it before 2 years ago, you are covered by warranty. Remember this model is not avaiable anymore....you will have to choose another U$150 Logitech product. Logitech didn't even asked me to send them my "mute" Pure-Fi Elite...
Hello burrow31. There maybe a switch located on the fan stating 'remote/manual'. Check your manual. Remove the battiers in your remote and short out the battery contact terminals. Reinstall the battiers, start the fan and after fan has reached set speed press & hold fan speed button for one second. Still no speed change contact the Mgfr. with model & serial #.
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