Instrument gauges only reading half of what they should

[nik1093]

Hey guys,
I have a 1979 D50 with the 2.0. After installing my weber carb, things have gotten funky in the truck.
My dash gauges have been acting really weird lately. First off, when I start my truck I have to rev it to 2000 rpm to get the alternator to start charging. Once I rev it the buzzer will buzz and the seat belt light will come on like it's just starting up. After that my gauges will only read half of what they should. When I fill my fuel tank full it shows half a tank, same with temp gauge. My alt light looks like it's half as bright as it should be. The speedo still works fine because thats all mechanical. If I am at a red light to long my gauges start dropping even lower. I am not sure if there is a voltage regulator in the dash or something that I need to look for. Also when I flip my turn signal switch and click it back, it starts my buzzer and seat belt cycle over again. Lemme know if you need anymore information, thanks for the help guys.

[Fordubishi]

Check the grounds first, a bad ground will cause the problems you're talking about

[BradMph]

lol, mine was doing that but, it was moisture seeping in a hole in floor where rubber cap fell out. The moisture created it's own rain forrest inside truck and dripped off condensation built up on sunroof glass, the next was history. Fixed it and checked all the plugs for residual moisture. Fordubishi is probably correct, ground that motor and whatever else needs one. Check neg battery ground chaining also.

[pennyman1]

also check the back of the fuse box - windshield leaks can cause wierd issues, along with weak prongs on the fuses themselves