HI,
At a dead end troubleshooting my ‘70 convertible heater issue. A/C works fine, evaporator and heater core replaced in 2007, Replaced heater valve, vacuum works. COLD-WARM cable works. Disconnected to manually move blend door and hear it moving. Heater hoses to and from the core are hot. Blower still blows cold air at full WARM. I was going to remove both heater hoses to the core and flush it, but with inlet and outlet hoses both hot from the water p[ump and back not sure that’s worth it. Engine temp gauge is in the normal zone so thermostat must be good. Would love NOT to have to remove the heater/A/C box again. Tough job for me. Any ideas are welcome.
The vac can on the far right (pass side) is the cold/fresh air door. Open glove box, undo cable screw to allow glove box door to open all the way. While running car see if that vac can works & moves lever/arm.
Thats the 1st step.
Thank you! The dash pad is out and I did notice that the vacuum motor wasn’t moving that vertical arm regardless of where I moved the selelctor. Didn’t think it was affecting the heat as it brings in fresh air from the grill below the windshield. Or so I thought. Will do.
Bill, you were right. Vacuum motor does not move vertical rod to change the Cold/Fresh air door. Pushed the lever arm down manually after car heated up. Heard and felt the door change position but heat didn’t come on. Because I loosened the heater core hoses outside the firewall some coolant leaked into the box onto the passenger side floor. The coolant was hot, so that’s a good sign. Thx. Joe
Now test the vac can/motor its self. I have a hand held vac pump to test things like this.
If it is good, next is the vac hose for that '“ circuit”. BTW, are the other vac can/door moving? If not then testing the vac can under the Pass fender is next….
I recommend a Ford Service Manual if you don’t already have one.
70 Cougar AC and Heater Dampers - Vacuum.pdf (219.4 KB)
70 Cougar AC and Heater Damper - Action.pdf (174.3 KB)
Thanks for the tip on the Vacuum Pump kit. Don’t own one yet. Yes, all the other vac motors are moving as I cycle through the A/C and heater settings. Determined to fix this heater issue. I appreciate your help.
Thanks for the links. Digging into my 1970 Shop Manual to try and sort this out.
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