Windstar heating problems

Hi everyone! A month ago, my 2001 Windstar stopped blowing warm air. “No problem”, says I, “probably just a bad thermostat”. But from under the dash was a ‘thump . . . thump . . .thump’ noise, maybe a ‘thump’ a second. I tried turning switches (blower on, off, hot cold, etc) but nothing changed. After a couple hours it stopped-but still no warm air.



Now the thump is back, and nothing I can do will stop it. Obviously the thump and no heat are connected, but I just can’t figure it out. Any suggestions about where I can start looking?



Thanks,

Dean

Blend air door?

Never even thought about it. I’ll check. Thanks.

first things first.

does the fan work? you say it doesn’t blow hot, does it blow at all?

have you found the heater hoses under the dash? are they warm?

is the engine temp gauge in the middle of the range (normal), assuming you don’t have an idiot light.

does the thump go away when you turn off the fan?

The blend door is broken and the motor keeps trying to move it – thump thump thump…

Fan works, blows cold no matter where I put the selector switch. Heater hoses warm, temp gauge shows warm (middle), thump continues until I turn the key off.