Heater problem

[knoslf]

well, replaced the heater control valve and still no heat, was told it could be this.

was told it may be this...'HVAC Heater Control Valve Solenoid', stealership told me this part is what gives the 'vacuum' to open the little flap to allow how water into the heater core to make hot air...I know the bottom one goes to the the control valve vacuum line but what does tie top go to and has anyone else had to replace this? Its tight on the passenger firewall..

 

[Monstar_est87]

Not sure our trucks use vacuum for the door actuators... I think its all electrical... Theres a heater control valve (see page 1) attached to the heater core hoses, under the coolant overflow... What problems are u having..?

 

[SunlitComet]

Thought it tapped into the PVC module on the left of Plenum but no reference in front of me. Should be a hard line running to it. Then the rubber one from it to water valve.

 

[knoslf]

Mine is just as in the pic, with 2 hoses going in and 2 hoses going to firewall...plus a vacuum hose that goes to the part(2nd pic), but i dont know what the other vacumm hose is for but im assuming if the part is bad whatever the other hose goes to probably isnt performing well either...just got a diagram of it too..the problems im having is no heat, well, it seems to put out some luke warm(as in just a tad bit warmer than cold) but never hot, at 1st it got hot if I closed off that vacuum hose between the control valve & the actuator on the firewall, but only did it once and in the past year i've replaced the WP, TS, and radiator/& cap

 

[retorq]

Not sure our trucks use vacuum for the door actuators... I think its all electrical... Theres a heater control valve (see page 1) attached to the heater core hoses, under the coolant overflow... What problems are u having..?

It uses a vacuum solenoid to control that heater valve that is pictured on page 1.

---------- Post added at 09:59 AM ---------- Previous post was at 09:56 AM ----------

Thought it tapped into the PVC module on the left of Plenum but no reference in front of me. Should be a hard line running to it. Then the rubber one from it to water valve.

No def not a hard line running to it on the TBIs.

 

[RedCrush]

Could also be that the door is not opening up under the dash.

 

[SunlitComet]

No def not a hard line running to it on the TBIs.

that comment was made for vortecs sorry.

 

[markrupp79]

Would this solenoid be more likely to fix my problem than the blend door actuator? I've searched and read through several threads but I am having difficulty finding symptoms exactly like mine.

A/C is working fine, temperature and zone controls. When the A/C is off, the floor vents are blowing air which turns hot after a short while. It just cooks your feet. Turn the A/C on and the floor vents shut off until you select them with the knob.

97 Tahoe (new to me)

Thank you...

 

[SunlitComet]

normally the valve only closes when the temp knob is on max cold detent. even still temp door would keep most of it out if not all.