Top Answer
User Avatar
Wiki User
Answered 2007-09-12 00:17:36

You have a bad vacuum reservoir or leaking vacuum line. Vacuum is usedd to control the air duct doors in your system and when you accelerate, the vacuum supply is greatly reduced...causing the duct doors to "default" to the defrost position.

User Avatar

Your Answer


Still have questions?

Related Questions

What would cause engine noise on 97 dodge caravan only when ac or defroster is on and only when accelerating?

Loose belt - will sound like a screeching noise.

Why would a 1993 Lincoln Continental Power Steering overheat?

only if it doesnt have fluid.

Why would the brakes stop working on a 1974 Lincoln Continental?

Brake Booster needs replaceing

Does a 1991 Lincoln Continental Have Aluminum Heads?

On a 1991 Lincoln Continental : I'm not a mechanic / technician but I have never heard of aluminum heads for the 3.8 litre Ford V6 engine So , I would assume they are cast iron

What type of freon uses my Lincoln continental 1989?

Would have been built for R12, can be converted to R134a.

Why would the air conditioner blow hot air in a 2000 Lincoln continental?

You might need freon

Would replacing the battery and alternator on a 2002 Lincoln Continental affect the power seats?

No, as being a master mechanic, it would have nothing to do with it.

What is a example of something that is not Accelerating?

A person walking in a straight line at a constant speed would not be accelerating. A person standing still in one spot would not be accelerating.

Where is the neutral safety switch located on a 1997 Lincoln continental?

That would be found on the transmission where the linkage hooks up.

What would cause a 1994 Lincoln Continental to turn but not start Not the battery?

It isprobably not getting fuel or not getting spark.

What would be the problem for rear defogger not working on a expedition?

Check that the wire on the rear defroster is connected to the defroster. If broken off repair it.

Why would the air bag light be blinking code 36 on a 2001 Lincoln Continental?

There is a problem with the SRS...have a dealer check it.

What kind of car is the same name as a hotel breakfast?

Lincoln Continental, although some people would call this a boat, not a car.

Why would your 1997 Lincoln Continental be sitting low in the rear?

Check the air bag suspension. Also, the pump may be bad.

Would a bad oil sending unit cause the warning ding on a 1994 Lincoln Continental? Tappet Brothers know all.

Why would 95 Lincoln Continental crank but not start intermittently?

I had the same issue with was the crank/fuel sensor...cost - 50.00 for part

Is it possible to be accelerating and traveling at a constant speed?

Yes. You can travel in a circle at constant speed, but you would still be accelerating because your direction would be changing constantly.

Type of brake fluid to use for a 1974 Lincoln Continental Mark IV? shows DOT 3 or 4 ( I would use 3 )

Why would a 99 galant stall when accelerating fast and okay when accelerating slow?

Check the fuel filter or the fuel pump.

Why does a car shake only when accelerating?

Only when accelerating, I would suspect a broken motor mount or bad CV joint.

Would you tell me what is the meaning of accelerando?

gradually accelerating

Why does your Air conditioning go from vent to defrost when accelerating?

Mainly because you don't need a fogged up windshield if you are driving fast. Seriously, the defroster setting is where most autos go to if there is a problem with vacuum. If nothing worked in your dash controls, the one thing you would still need would be the defroster, so that is the default setting. Now, when you accelerate fast, the throttle is wide open, and there is no vacuum, or it is very low, so with low vacuum the control reverts back to defrost. It would be the same as if you un hooked a vacuum line and did not feed your dash controls, you would only have defrost.

Why would the blower of a 1990 Lincoln Town Car switch from the heater to the vent to defrost when accelerating or decelerating?

the heater controls are run on engine vacuum. When a engine is accelerating it has a drop in vacuum. There is a one way check valve that keep vacuum in the heater circuit that has gone bad. You could have it fixed or you can deal with it, its not that big of a deal

Where would you plug in a computer on a 1983 Lincoln Continental?

On the '83 Conti, there should be a cigarette lighter at the bottom of the console . You'll have to buy an adapter for your computer to plug into it.

Where is the reset for seats on 2001 Lincoln Continental?

there is not a reset, also you have to do is get the seats where you would like to have them and then press the memory button again and it should set to the new position.