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No Hot Air (cont)[ALL/1988] posted by John Acampora on
Sunday, 22 February 1998, at 4:59 p.m.
Still not getting hot air out of auto air system in 87 765T.
I pulled the glove box to check the Shutter Vaccum motor that opens the heater door. The control rod does not move when I change the temperator of functions on the temp control system. I removed the vaccum motor and move the control rod by hand. That does change the air flow to the foot area, put still no hot air. Does the shutter vaccum motor need a certain temperature before it will turn on? Could it be the heater valve is not working, thus not causing the activation of the vaccume motor?
I watched the Heater Water Valve that goes into the heater core. When the engine is off it is closed (or is not pull inward). With the engine on and heater on, it is still in the same position. Should'nt it change position with the heater on? Is it a bad heater valve or a lack of vaccum that is causing ? How can I tell if I am getting sufficient vaccum to the valve?
Could the themostat have anything to do with this? Is there a way of checking to see if it is working?
Appreciate any help
John
87 765T 123K
Re: No Hot Air (cont)[ALL/1988] posted by Bill Meacham on
Sunday, 22 February 1998, at 9:07 p.m.
John,
Yes the heater valve next to the firewall should definitely change position when turning on the heater. You may need to start there and work your way back to the programmer.
If you have a vacuum pump source (like the Mityvac from IPD) you could check out the heater valve for correct operation. If it works, you could then hook it into the end of the vacuum line from the water valve which terminates at the rotary vacuum switch in the programmer (gray color hose) and check the valve again. If that works, check to make sure you have source vacuum from the motor in the programmer. (You could use the vacuum pump and put it in place of the motor in the programmer to see if the heater then works). That's about the end of my knowledge on the climate control system. Hope it helps.
Bill
86 740T
Re: No Hot Air (cont)[ALL/1988] posted by abe crombie on
Sunday, 22 February 1998, at 9:30 p.m.
That hot water valve is opened (no vacuum) unless you go to full cold positon with temp knob at which time the ACC system will supply vacuum to pull linkage on water valve to close it. Seeing no motion is not a problem unless it is stuck in the closed position already. Pull line off valve and run a vac hose from a nipple on intake where you can detect vacuum and see if valve moves when vac applied and retracts to open when vac is removed.