Asked by Mar 10, 2016 at 07:23 PM about the 1994 GMC Sierra 1500 C1500 SL Standard Cab LB

Question type: Maintenance & Repair

I have a 94 GMC Sierra 1500 2wd 4.3 motor, I have
replaced heater core 3x thermostat 2x I have put
new actuators in it bought new hoses, it's blowing
out warm air but not hot, my defrosters aren't
working very well is there anything I can try before I
change the control box out

1 Answer


one suggestion, go out under the hood where the inlet hose and the outlet hose go to the heater core do they feel pretty much the same. if no fan is blowing across they should feel about equal, yet hot. if they are i would suspect the controls. but could you have the wires or pulled of a vac line that controls them, is the vent the brings in outside area completely shutting off. just some ideas.

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