Cluster problem,transmation temp gage ,engine temp gage not working but in info message center flashing other problem like battery voltage flashing but working gage no high beem indecater only sometimes no cruse indecater nmo gas gage also flashing service 4x4 and securty.

More than likely a broken wire, corroded connector or a chafed wire.

Are any DTC'S - diagnostic trouble code's stored in any module ? BCM - body control module , PCM - engine computer ,IPC etc.... It's the temp. gauge not thermostate gauge Did it work after replacing the thermostate an coolant temp sensor ?
Engine Coolant Temperature Gage
The instrument panel cluster (IPC) displays the engine coolant temperature as determined by the engine control module (ECM). The IPC receives a serial data message from the ECM indicating the engine coolant temperature. The engine coolant temperature gage defaults to 38°C (100°F) if:
• The ECM detects a malfunction in the engine coolant temperature sensor circuit.
• The IPC detects a loss of serial data communications from the BCM.

The first thing too do would be to hook up a factory or some other type of professional scan tool an see what the temp. sensor is telling the engine computer an if the BCM is showing the same temp. data . And is that info. getting to the instrument cluster . Knowledge of how it all works an proper diagnostic technique is the key to finding the problem .
If the IPC is see same temp the engine computer is an the gauge isn't working something is wrong with the gauge itself. New instrument cluster would be needed .

Without testing ,hard to say for sure . Gauge could be going bad or the engine coolant temp sensor , wiring for sensor , PCM/ECM etc..... Knowing where that info originates an how it gets to the instrument cluster gauge is key in diagnosing the problem . Having worked at GM dealer ships an having correct tools an information gives me an edge over most . Most people would just replace parts an hope it fixes it . The first place to start would be to hook up a factory or professional scan tool an check for DTC'S - diagnostic trouble codes in the instrument cluster an the PCM/ECM . View live data inputs from the coolant temp sensor to the PCM?ECM - engine computer ,also see if that same info is getting to the instrument cluster . Most usually , if the problem is happening at the time we can't find the fault .
The Coolant temp sensor is an input to the PCM , the PCM sends this if to the instrument cluster on the serial data network . Don't know if you know what that is ?

Engine Coolant Temperature Gage
The instrument panel cluster (IPC) displays the engine coolant temperature as determined by the engine control module (ECM). The IPC receives a serial data message from the ECM indicating the engine coolant temperature. The engine coolant temperature gage defaults to 100°F (40°C) or below if:
• The ECM detects a malfunction in the engine coolant temperature sensor circuit.
• The IPC detects a loss of serial data communications with the BCM.
• The BCM detects a loss of serial data communications with the ECM.

GM did have problems with stepper motors inside instrument clusters 2003 to 2006 . Stepper motors are what control the gauge needles .
https://www.youtube.com/watch?v=oTm2oDx-_GM

Doesn't have a fuse just for the gauges . B+ power supply for the whole instrument cluster . Gauge info comes from the BCM - body control module an the PCM - powertrain control modules over serial data network (GMLAN ) The instrument cluster has electronics inside ,plus software . GM did have stepper motor problems in their instrument clusters from 2003 to 2006 . Your best bet , take it to a qualified repair shop.
How to repair GM Instrument Cluster Speedometer Gauge Stepper
Engine Coolant Temperature Gage
The engine control module (ECM) sends the coolant temperature to the instrument panel cluster (IPC) via serial data circuit. The IPC receives serial data messages from the BCM indicating the engine coolant temperature. The engine coolant temperature (ECT) gage, if equipped, defaults to 75°C (160°F) or below if:
• The ECM detects a malfunction in the ECT sensor circuit.
• The IPC detects a loss of serial data communications with the ECM.
Refer to Cooling System Description and Operation for more information.
Speedometer
The instrument panel cluster (IPC) displays the vehicle speed based on the information from the engine control module (ECM). The ECM sends a 4,000 pulse per mile signal to the cluster discretely. The IPC calculates the vehicle speed using the time difference between consecutive pulses. The speedometer will default to zero if the time duration since the last speed pulse is greater than or equal to one second.

Fuel Gage Description and Operation
The ECM uses the signal circuits of the primary and secondary fuel level senders to calculate the percentage of fuel remaining in the fuel tank. The ECM supplies 5 volts via the 5 volt reference circuit and also provides a low reference to the primary and secondary fuel level senders. When the fuel tank is full, the resistance of both fuel level senders are high and the ECM senses a high signal voltage on both the signal circuits of the primary fuel level sender and the secondary fuel level sender. When the fuel tank is empty, the resistance of both fuel level senders are low and the ECM senses a low signal voltage on both the signal circuits of the primary fuel level sender and the secondary fuel level sender. The engine control module (ECM) sends fuel level information to the instrument panel cluster (IPC) via serial data circuit. The instrument panel cluster (IPC) displays the fuel level information in the fuel gage. When the fuel level is less than a predetermined value, the low fuel message displays in the driver information center (DIC).
The fuel gage defaults to empty if:
• The ECM detects a malfunction in the fuel level sensor circuit.
• The IPC detects a loss of serial data communications with the ECM.

NO , there is not a fuse just for those two thing's ! There are two power supply's for the whole insturment cluster . You could need a new cluster or the ECM isn't sending this info. to the cluster . Could have DTC'S - diagnostic trouble codes stored in the PCM or the insturment cluster . Without knowing how this works (insturment cluster gets it's info.) Your best bet , take it to a qualified repair shop that has the knowledge and test equipment to diagnose this problem.
Engine Oil Pressure Gage
The instrument panel cluster (IPC) displays the engine oil pressure as determined by the engine control module (ECM). The IPC receives a serial data message from the ECM indicating the engine oil pressure. The engine oil pressure gage defaults to 0 psi (0 kPa) or below if:
• The ECM detects a malfunction in the engine oil pressure sensor circuit.
• The IPC detects a loss of serial data communications with the ECM.
For the 4.2L LL8, the ECM uses an engine oil switch that is open when the oil pressure is normal and closed when the oil pressure is low. At normal pressure, the engine oil pressure gage will display 275 kPa (40 psi). At low pressure, the gage will go to 0 kPa and the low pressure warning will be displayed in the driver information center (DIC). At high pressure, the gage will display 551 kPa (80 psi). Any values between these three values are calculated values determined by the ECM.

Voltmeter
The instrument panel cluster (IPC) displays the vehicle voltage based on the information from the body control module (BCM). The IPC uses the serial data information from the BCM to provide a voltage level indication on the voltmeter.

DTC P0521: Engine Oil Pressure (EOP) Sensor Performance

DTC P0522 Engine Oil Pressure (EOP) Sensor Circuit Low Voltage
DTC P0523 Engine Oil Pressure (EOP) Sensor Circuit High Voltage

Volt Gage Inaccurate or Inoperative
2
Install a scan tool.
Turn the ignition ON, with the engine OFF.
With the scan tool, perform the instrument panel cluster (IPC) gauges output control.
Does the volt gauge move up and down when commanded?

Hi Julia , why do you believe you need to find the temp sensor ? Temp gauge not working ? The cooling Temp sensor is a input to the PCM / ECM - engine computer .
Engine Coolant Temperature Gage
The instrument panel cluster (IPC) displays the engine coolant temperature (ECT) as determined by the powertrain control module (PCM) or the powertrain control module (PCM). The IPC receives a class 2 message from the PCM indicating the ECT. The range on the ECT gage is between 60-125°C (140-260°F). The ECT gage defaults to 60°C (140°F) or below if the PCM detects a malfunction in the ECT sensor circuit. Refer to Cooling System Description and Operation .
Would have DTC- diagnostic trouble code stored in Instrument cluster or the check engine light would be on . Before replacing a part you may not need take it to a qualified repair shop to have it diagnosed .

Probably,factory installed alternator has failed and vehivle is only using battery power.Suggestion:Start engine and check available voltage at battery with DVOM.SHOULD be 13.9 volts minimum and about 14.5 max.if not in range listed.please have alternator checked for failure.

with a scan tool read data of transmission look for trans,temp.
if it said the same thing as the temp gauge in cluster
temp sensor inside transmission send info to PCM then pcm send message to cluster

Euc? Do you mean ecu, the computer? Don't think so. Something in the cluster, maybe the little voltage regulator on the back of the cluster. But if the engine light is flashing, definitely have it scanned for trouble codes, first, to see why the light is on. The light may indicate a poor link or connection with the cluster.

You need to contact the dealer parts dept or a salvage yard with a cross over reference book for this model and years you have.