'00 Limited No Heat after battery disconnected

[Drew76]

Had my truck parked in my shop for last 2 weekends with battery disconnected while I did maintenance, reconnected and test drove tonight and have no heat from dash.

Maintenance was not related to Engine or cooling system, I did the following:

Front/Rear diff fluid change
Transfer case fluid change
Rear shocks
Air Lift bag install
Upper/lower rear control arm bushings
Panhard bar bushings

Truck is heating up normally, OEM new Tstat 1 year ago with coolant drain and flush from green to pink at the same time. Climate control module swapped with a repaired one 2016, all buttons seem to be working.

Rear heater is putting out heat, all hoses at heater valve on firewall seem hot, would likely culprit be servo motor behind dash near passenger side?

Anyone know which 2 lines are in and out of heater core?

 

[alumarine]

Is it possible to manually adjust the heater valve on the firewall on the limiteds?

 

[Drew76]

It is possible, I just took the cable off and manually opened it all the way, air got warmer but not hot, pipes in and out of heater core are hot. Behind center console I can see servo motor working while I change temp setting from hot to cold but the heater valve never moves.

When I change source from outdoor air to recirc I can hear/feel the appropriate actuator stroking, same when I change vent output setting from windshield/feet etc...

I've had the heater core get clogged in my Silverado and changed it out myself but in that case the return line from the core was cold so I'm not sure in this case. I guess it can't hurt to flush out the core anyway.

 

[alumarine]

If the valve is open but you have poor heat it could also be the blend door.

 

[Drew76]

If the valve is open but you have poor heat it could also be the blend door.

Yes you are right - I removed the cable closest to the front of the dash from the blend door actuator and now with the heater valve on the firewall manually open I get perfect heat with the temp set to hot, and colder when set to cold.

It seems like the actuator is stroking more with no cable connected, so the door seems to work fine, would the problem be the cable or what do you think?

Also I'm assuming that the cable i disconnected runs from the heater valve at one end to the actuator at the other but I'm not sure.

 

[alumarine]

Sorry but I've exhausted my knowledge on those systems.
I have the manual controls not the auto like yours.

Hopefully someone will come along with more help.