heating

[conan2]

i have a 1999 taurus with a 3.0 engine it has had a new heater core,thermostat,and the system has been flushed,it also has the climate control system.my problem is i get good heat coming out the vents after about 10 minutes but only warm heat coming out of the defroster,can you help im going crazy and its costing me a lot of money.thanks

[Dan_in_WA]

The A/C system operates when the defroster is on - this is to de-humidify the air being blown on to the windshield and prevent fogging. See the Owner's Manual.

There may be a problem with the duct system; like a vaccum solenoid is leaking or something. The heat duct door should be fully open, IIRC.

If you have the electronic Climate Control, there is a self-diagnostic program that you can run, but I don't know how to actuate it on the '99 Taurii. A real competent shop should be able to help you out.

Lastly, if you're already into spending money, go to www.helminc.com and get the factory service manuals. Those books are 4 inches thick and are WELL worth the cost! They will cover things like starting the self-diagnostics on Climate Control.

Good luck, and keep us posted.

[mikeo550]

well the good news is you knocked out half the things you were going to need to replace in the future... the bad news is once the heat stops working it never comes back... try a water pump... vacumm... other than that bundle up!

[wwest]

New design by idiots.

Somebody decided that using the A/C to dehumdify the defrost/defog/demist windshield airflow would always be sufficient to remove and prevent condensation.

It isn't.

When you want to use defrost/defog/demist turn the heat setpoint UP first.

Below about 55F it is only by EXCEPTION that the A/C is efficient enough, depends on the relative humidity of the incoming airside airflow.