I have a 1993 Tahoe Lt S10 blazer that has been sitting for 7 years, new fuel pump and some cleaning of the tank got in back running, water in radiator was orange so I flushed it, need to go back and flush it better but I noticed my temp gauge is non existent it doesn’t work at all, any idea what the issue may be as I do not know my way around the cooling system?

 

Have you checked the fuses runs the temp gage that might be bad. If not, it might be temperature sensor is bad or the thermostat is bad.