Purchased a used 2004 mercury mountaineer and it didn't come with a owner manual and don't know what some of the functions are for.

In a 2004 Mercury Mountaineer, the fuse for the dashboard lights and taillights is typically located in the fuse box under the dashboard on the driver's side of the vehicle. The exact location of the fuse and the fuse number may vary depending on the specific model of Mountaineer you have.
To find the correct fuse, you will need to refer to the owner's manual for your vehicle. The owner's manual should have a diagram of the fuse box, which will show the location and function of each fuse. Alternatively, you can also check the label on the inside of the fuse box cover, which should also list the function of each fuse.
Once you have located the correct fuse, you can use a fuse tester or a multimeter to test the fuse to see if it is functioning properly. If the fuse is blown, you will need to replace it with a new one of the same rating. It is important to use a fuse with the correct amperage rating to avoid damaging the electrical system. If you are unsure which fuse to use, it is recommended to consult a professional mechanic or refer to the owner's manual for guidance.

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https://www.manualslib.com/manual/231991/Mercury-2004-Mountaineer.html

You can purchase them at this site:

Is the battery good in it?

That is a lot of don't knows


That tells me your better off at a repair shop

Why not check all the fuses

If one blew,it will blow again, until you
fix the real problem

If one window works, it won't be a fuse

The most common would be a window
switch you use the most,followed by a window
regulator,then a fail motor.

You should have an owners manual for
all your vehicles to look up fuses & lamps

Helm.Com --is where you go for a Ford & other
make manuals

Fuse,Switch or Control Knob,Mirror Motor or Module
if one applies

Don't know if you can control or check with a scanner
I would have to look at my software to see if ford offers that

I have a 2003 mercury mountaineer with a dying battery problem and we narrowed it to fuse 1 and 29 and they are labeled PJB in the owners manual....if you find out what that means I would like to know too. I don't know if that will help you any

I think you should go for manual first after that it will be easy for u to solve your problem. I had visited this site past 2 months before for my vehicle and find it quite helpful may be you will also get something useful here
Mercury Mountaineer 2002 2005 Factory Service SHop repair manual Download

Initially look at the fuses. The windows will have their own fuse and the radio may work on the same fuse as the gauges. The fuses must be in the main fuse box. The position and function of the fuses is normally marked on the inside of the fuse box cover and also in the owner's handbook. If you don't come right with these, work your way through the fuses looking for a blown ones. A small pair of pliers will ease removal of the fuses.

they can go bad-swap it out with another that you don't need, just to try and see if it is the relay-listed are relays that might only control, for instance, the rear window defroster-generally, relays are all the same, some just get used heavily and some don't (i.e., ABS)-worth a try