Why does temperature gauge on 1991 Chevrolet 1500 Silverado flashes?

[jld_dds]

This is the gauge for the heater. I am getting very little heat, even when the truck is warmed up.

 

[httnmrtt]

You are low on engine coolant and have an air bubble in the heater core. That's why your idiot light is flashing and you're not getting any heat. Top off your radiator with the engine running to purge the heater.

 

[universe man]

check your thermostat and you coolant levels to see if the thermostat is operating at designated temp

 

[dodge man]

low coolant levels will cause it to run a little hot and not give off good heat,recheck the coolant levels in it and make sure they are full,and you may have to bleed the air from the cooling system to get it to work right,good luck.

 

[kelly_f_1999]

truck is over heating would be first sign could be low coolant a belt slipping dirty radator and really if your not gettting heat id say thermostat stuck or its out of coolant

 

[Pedal2TheMetal45]

HI
Check the coolant level in the radiator its self not the overflow tank... with the motor cold the fluid in the radiator should be all the way to the top or no more than 1 below the top.. with low coolant the motor well over heat (the flashing light) and the water pump can not move enough coolant to supply the heating system with hot coolant.
simple fix
good luck
tim