[:@]I have a 1993 Ford Thunderbird V6 3.8L. My heat quit working. The blower motor is working that I know of, because I have air blowing out. I back flushed it to see if that was the problem. I put a new heater core on it, and that still didn't work. What else can I check. This car is my only transportation until I get my taxes back. What else could be the problem. Thank you. Freezing Dan [&:]

 

From what I understand the actuators for various environmental controls are vacuum controlled. It is also my understanding that the default position for those controls when there is a loss of vacuum is defrost, so check and see if the air flow you do have is coming through the defrost vents by your windshield. If that is the case I would start checking to see if your vacuum pump or lines are good to go. I have a manual for my 1997 Tbird but it is at work or I would see if it covers your Model year and see for myself how that is controlled.

Let us know what you find and hopefully someone with more knowledge of the Birds will swing by and post.

Good Luck.

 

Some newer cars use a vacuum operated valve inline with (spliced in the middle of) one of the heater hoses. The valve shuts off coolant flow to the heater core to facilitate quicker engine warm-ups. The valve can be broken inside and blocking the flow of hot coolant to the heater core. It may look OK from the outside - but inside is what counts. Also check the vacuum effect on it to be sure it's operating and the vacuum diaphragm isn't shot. Aside from this if you're able to unhook both coolant hoses (vacuum part not hooked in) and blow air from one side coolant hose and feel it coming out the other - it's open in the tubes. So then you want to try cleaning out the plenum (air vents). They may have fresh air intake which can pull in debris and clog the effects of the heater core. Also this can become an unintentional fire hazard as the heater core could ignite dry debris. Last, a check of the vacuum modulators to the individual vent doors and vacuum lines under the dash should be made. Aside from the actual dash switchwith any cablingandfuse boxfuses (easy stuff) that about covers it.

 

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