My oil pressure gage is reading at over 80 when the manual says normal is 40, I have a 2005 trailblazer ls 2wd

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?

Check gages means that one of the gages is reading an abnormal reading, like hot engine oil pressure issues, charging system voltage, pay attention next time it happens to the readings on the gages for something out of the normal

No damage will occur. Have you checked the oil pressure with a manual test gage? If not do that and please understand GM oil pressure gages are prone to reading high pressure when the sender is defective.

Oil pressure gage

who has em.
what to buy it
how to read it.
hot of fix it?\
or?

on Jeep Trailblazer? really?

It could be the sending unit. If the truck is low on oil it will cause something similar. Be sure the oil level is topped up. The only way to be sure it so measure the actual oil pressure at the engine with a proper gauge..

OIL PRESSURE GAUGE SHOULD HAVE STEADY READING.IF FLUATING I WOULD HAVE OIL PRESSURE CHECK SOUND LIKE FAULTY OIL PRESSURE REGULATOR.

You may have a bad oil pressure sending unit. The kit they are talking about, I believe is a rebuild kit, not the entire pump. Usally the kit consists of a couple rotors and seals. You would take the old parts out the oil pump housing, and install the new ones. But you want to make sure that all the clearances are within specs. I'd try the sending unit first.

CHECK GAGES light (1) indicates a potential engine failure(low oil pressure, low coolant, coolant overheating) has occurred.
· Check gages and shut down engine. Gages should read as follows: Oil pressure 5 to 10 psi (34 to 69 kPa) at idle; Water Temp gage below 230 degrees (110 C).
· Check engine oil level (Para 2-11) if OIL PRESS gage indicates low reading. Check coolant level (Para 2-11) if Water Temp gage indicates high reading. Notify Unit Maintenance if levels are low.

If CHECK ENGINE light (2) is on, check engine oil pressure gage (3) and water temperature gage (4). If both indicate normal, proceed with mission and then notify Unit Maintenance. If either one does not indicate normal, stop engine immediately and notify Unit Maintenance

Most likely the oil pressure sending unit is going bad or has a loose connection,but it would be safe to have a manual oil pressure test done to be sure it's not a problem with the oil pump.

it is probably the oil sending unit if you have access to a direct reading oil pressure gauge put it on and if oil pressure is reading normal replace sender