My factory temp gauge in dash next to oil pressure gauge won't register at all.I sent the gauge to tachman, told him it did'nt work and he just filled the fluid in it said it would work but it does'nt. I put 3 different sending units in, thinking this was the problem, new Delco sending unit fine. Is there a company that fixes these? Is there a FACTORY replacement? I just need the temp gauge. Anybody have a good used factory temp gauge for my factory 66 CHEVELLE cluster?