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Virtual Wrench
Virtual Wrench, Ford Mechanic
Category: Ford
Satisfied Customers: 14620
Experience:  35 years Master Mechanic
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1999 Lincoln Navigator: blows out cold air..come on and blow hot air

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Hi there, i have a 1999 Lincoln Navigator. The problem is with the heating system, even when the heat is turned up full it still blows out cold air. Every now and again it will come on and blow hot air out but very rarely. All the dash heater controls work, the temp switches, the switches that direct the air flow in the cabin and the fan blower control. The only problem is that 99% of the time the car will not blow out hot air even when the tempreture control is at its highest level. This is also the case when the controls are set to auto. Can somebody give me an idea of what the problem may be?
Customer: replied 8 years ago.

1999 Lincoln Navigator 5.4 V8

Already Tried:
I have taken the vehicle to a mechanic and an auto electrician and also supplied wiring diagrams (which i got earlier of another expert on this website) but i live in Northern Ireland and to tell you the truth these guys, because it is an American car, seem to be clueless in what they are doing and seem to be fobbing me off with answers so they can screw me out of more money.



Has the thermostat been replaced?

Customer: replied 8 years ago.
Hi there thanks for the quick reply, i bought the vehicle 5 months ago during the summer, so to tell you the truth im not sure if the thermostat has been replaced. What i do know is the vehicle was running of at least on cylinder and i had to have two coils replaced and the spark plugs. When the mechanic tried to remove the spark plugs he found they where ceased in so it does not seem as if much maintenance has been done on the vehicle so the chances of a thermostat being replaced is very low.

Thank you,


99% of the time its going to be the thermostat opening up too soon and not allowing the engine coolant to get hot enough to allow the heater to work right. Now this is providint that the coolant fluid level is full. It is VERY common to do this. It's a simple repair and the parts cost less than $15. I have included the instuctions for replacing it, maybe its something you feel comfortable doing yourself, if not, just show the shop and they will know what to do.





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