Front-passenger & driver heat not working, only blows cold air

[Don40]

We've posted other threads about our original problem. Long story short, we pulled the motor & put it back in. We had a broken valve spring on #8. We put in a new torque converter, thermostat, tune up. Everything is workng great, it's running wonderful & problem fixed. New problem- there's no heat in the driver & passenger side front. It will only blow cold air, no heat. The back blows hot. Can't figure it out, please help. Thanks. 2003 Explorer Limited V8

 

[Don40]

I messed with the heater situation a little more. After reading through 2 hours of posts, I unhooked the vacuum to the heater valve on the passenger side valve cover. There's no vacuum going to the valve controller. I unhooked the actuator from the valve & opened the valve manually & now I have heat in the front of the vehicle. But, why is there no vacuum to control the actuator? When everything was hooked up you should be able to watch the actuator open & close the valve with somebody changing the heater switch from hot to cold. Please help. I followed a grey colored vacuum line hooked to the actuator through the fire wall & under the passenger dash. It looks good. it goes to a valve body with about 4 other vacuum lines that hooks into some other valve body for probably heater controls.

 

[river.j.rat]

Hi, I also have an '03 Explorer LTD with no heat in the front or the rear heaters. I turned the heat to max both places and only cold air. I checked the water valve near the passenger valve cover, under the hood. There is no vacuum at the actuator. I used my handy dandy hand vacuum pump and the valve actuates, but I don't know when the valve is on or off. The water pipes that lead to the heater cores seem to get to about 120 degrees or so as I can hang on to them without getting burned. I traced the two vacuum lines that go through the firewall and they seem to be hooked up normally. The black one is the source from the intake manifold that hooks to a small reservoir and then to this vacuum manifold mounted near the transmission hump on the passenger side. There appears to be a small amount of vacuum at the "T" that connects to the reservoir, not real strong, but some. The HVAC system is the dual control with no knobs to turn, just set the temperature and let 'er run. The A/C works fine and the doors seem to switch when you push the different buttons.

River Rat