Hey gang i have 1997 gmc jimmy 4x4 with a vortec v6 i have no heat i know for sure that my heater core is not plugged the fan motor is blowing hard but only cold air or no air comes out what should i look for to fix this?

 

Is the blend door functioning?

 

A plugged heater core has no relation to the fan motors operation. A plugged heater core means the inside of the core is plugged but air from the fan motor will still pass through the core.

You should check the heater hoses at the firewall going to the heater core. If they are both hot then the core is probably not plugged. If one is hot and the other significantly cooler than you have a blockage in the core.

if both hoses are hot your blend door may not be functioning properly. Use the search feature of this forum and search blend door. It's been covered numerous times. Let us know what you find out.

 

could be one of a million actual issues... looks like your about to pull your dash apart to figure this one - as far as the heat goes you can't tell if the heater core is clogged or just has an air bubble in it preventing transfer of heat to the exchanger. then again there could be leaf/dirt debris on the ac evap core too.

 

^^^ he's right, it could be a dozen things.

simple thermostat issue for no heat. you'll want to flush everything out while you're at it.


as for no air coming out the vents..........well...you're more than likely gonna need to pull the dash out (have fun!) it sounds like either a vacuum line has come off, or is broken.

an since there is no room to get up behind the dash (@ least not for my forearms!) you'll have a bit of an issue truing to check the hose connections @ the vacuum diaphrams.

you never mentioned if your truck has the electronic Auto Climate Control in it. i think it came out in '98, but i'm not 100% sure.

 

thank for all the help got my blend door swapped out but i have a new problem. my temp gauge keeps bouncing up and down replaced the thermostat and the sensor the computer says the I'm at the correct operating temp what do i need to check next i need to now when and if i start running hot

 

should start a new thread for this particular problem but maybe the gauge is just shot or has a bad connection/ground.

 

I have a 97 4x4 vortec v6 my temp gauge is not reading correctly i have changed the sensor and the thermostat computer says i'm operating at the right temperature. my gauge will bottom out a few times before it settles down but it still reads 15-20 degrees hotter than the computer says i DO NOT have a digital dash what do i need to check for?

 

*Combining 3 different threads on the same issues. Please keep it all in one thread so we can follow what is being done and remember that double posting is against Forum rules.*

 

Sorry rriddle3 - i suggested he start a new thread for this new issue of the temp gauge bouncing around rather than continuing on with a thread regarding lack of heat.

sorry to you as well rcampbell33, this is MY fault u got the warning :/