[baseballZ]

This morn I got in my '78 280Z and...no defroster,no heat , nothing. Air continued to blow out the center vents but didn't get hot. This was all working fine a week ago. I took off the cover (face plate???) of the heater controls to look in there,crawled all up under the blower (thats a lot of fun!) and everything seems to be o.k.(obviously it ain't) Any ideas....could it be electrical,not mechanical? The A/C works,the vent works ,but everything else acts like vent.I hope someone can help me quickly 'cause I kinda want to fix it tonight (while I have it all apart)
Thanks a lot

 

[Dave_260Z]

I've been battling AC/Heater trouble. On my 260 there's a vacuum hose that controls the vent flap for the heater - maybe someone kicked off the vacuum hose?
Otherwise, maybe the water control valve has given up & no longer switches the hot water through the coils.

 

[baseballZ]

Thanks Dave for responding
I'm gonna go check vacuum lines...I hope its not the valve.I don't know why air just keeps coming thru the front...not the top,no matter what the setting

 

[Charles Freiss]

yes check the vacuum hoses. On my 76 280 the hose was dry-rot at the point it connected to the vacuum tube. That the chalky-white bottle on the passenger side of car in engine bay. If it worked before this is where to start. Chuck

 

[Lee Smith]

To have heat & vent only. You can bypas all junk on right side of engin bay. Take vac. line to heat-ac, where it goes through fire wall, directly to vac. port on intake manafold.
The A/C may not work next summer. It looked to me that all the junk was to actuate a throtel advance in A/C mode.