i have no heat at all.i will turn the heat on and turn to high and nothing.if you listen very carefully you can hear a very very faint nose.not sure what it is.any ideas what it could be.its getting cold out

thanks for the help

truck is 88 gmc s-15 jimmy 4.3l engine

Need more info.
Is rad full of coolant?
Does fan blower work or blow good?
Does engine warm up to 195 degrees?
Does vents switch good?
Does heater tempt control go to cold and then to warm/hot?

Has heater controls got good engine vacuum?
Can you hear vacuum leakage?

when i turn it on nothing blows out of the vents.only way i get a little heat is if i just turn it on heat and let the heat from the engine come in

If blower motor is not running work on it and circuitr to it.
Fuse/switch/resistor block.
Jumper motor with 12 volt fused jumper wire and see if it runs.
Let us know how it goes.

MT,
I have a simular problem with heater blowing cold air on my 2000 Blazer LT with the automatic temp control.
All the vent switches work correctly.
The engine temp is 190+.
The radiator and surge tank are full.
The heater core hoses are both HOT.
Can not hear any vacuum leaks. Do the vent doors
work with electric motors? There is like a cerval module unit mounted by the A/C and heater box. Does it control
the air door of A/C and heat? Would it be defective?
SD

MT,
I have a simular problem with heater blowing cold air on my 2000 Blazer LT with the automatic temp control.
All the vent switches work correctly.
The engine temp is 190+.
The radiator and surge tank are full.
The heater core hoses are both HOT.
Can not hear any vacuum leaks. Do the vent doors
work with electric motors? There is like a cerval module unit mounted by the A/C and heater box. Does it control
the air door of A/C and heat? Would it be defective?
SD


Best to start a new Thread/post on yours.

Tempture door is worked by the actuater motor,

Check it for moving cold to hot.
Go up to how to in s-10 forum.
Good information and picture.
http://www.automotiveforums.com/vbulletin/forumdisplay.php?f=2069

gunna try and see whats going on with the heat tomorrow is there a visual inspection i can do to see if its messed up.like is the cage on the motor supposed to spin freely if i try and spin it