What might cause my gauges not to work properly in my 2004 Chevy Trailblazer

...yes reduced or NO ground potential to the chassis...this connection comes off of the NEGATIVE battery cable and ends up at a ground lug...this ground lug is covered in corrosion from repeated high-amperage starts~ you MUST disassemble this connection and wirebrush both the lug and the chassis to assure 300 cold cranking amp potential and to provide NEGATIVE to the dashboard and it's components...kinda surprised that the CEL did not come on because under reduced power/ground potential these brain-boxes lose track of the sensor data and go into a kind of "fail safe" mode what keeps the engine running...brain-dead~....so in summation, wirebrush the 1/0 cable end and chassis and re-assemble them with a NEW battery as they get old quick with NO LEAD in them anymore~...you can test the ground at the dashboard...check for 12.5 unwavering volts~

...also relays will sporatically drop out...in other words, the ignition relay suffers from an undervoltage condition and drops out and then the ignition is dead...same for the fuel pump....they aren't failing to do their job....they just cannot get to ground...electronics Par-Broil themselves when NO ground is at hand~

your fuel gauge has a REGULATED (of it's own regulator) variable resistor...we definitely do not want this one to bounce around...unable to read it...that's why the thing works yet...it has it's own power regulation at hand~

the thermostat is not electrical....but the temperature sensor is~ this is what your computer decides the air/fuel mixture should be at ambient conditions...if bad the car won't run okay~

we alright still...you hangin' in there?~

Just fixed mine it's not a ground . Take your instrument cluster out and completely apart. Takes 10 minutes. Take the circuit board without gauge needles on it and plug it back into the truck carefully. Take a pencil with the rubber eraser side push on all the small compactors and resisted lightly. You will find one problem nears the two big round compactors the size of acorns. Mine was a retailer small flat resistor marked 205 on top. It was never factory soldered on one side. Soldered back . All is good. I had to set gauge points back at 0. Let truck warm up set temp just push the needle on where it should read 190 or so as before. Same with rpm. Fill tank then set . GPS speed then set and test . Oil should be 35 to 38 at idle. Your welcome ... high five it's easy they have computer machine welds their recall is because it missed a solder dang.

So I didn't need to buy a whole new cluster ?

2002 blazer half gauge don't work rpm speedster gos complete dead when stop then i get power back what would it be ty

2002blazer temperature rpm speedster and miles not working n also when stop at light go's complete dead the i get power back to restart what make this happen ty