Fuse # 4 2002 f 150

check and fix the point where the power wire is shorting out . Have you got the correct bulb in place as if you have a single point bulb and a double point in the connector that is a dead short and blown fuses again and again and again

You need factory wiring diagrams to work on any vehicle
If a fuse blows, it does so for a reason,& replacing it,is
not a fix.
Need a shop to work on the issue
If you loose one relay in 60 years of driving, that would be
a lot,so forget that,leave relay testing to people with
those skills

If the fuse blows on different trailers then it's all down to the vehicle. You either have incorrect wiring on the vehicle, a short OR the fuse is not of a high enough value to cope with the additional brake lights? You could try removing all the trailer bulbs EXCEPT the brake lights - e.g. if it's trying to power up the indicators too? That would stop the fuse blowing...... OR remove the brake bulbs from the vehicle & see if it operates the trailer without blowing...... Check the total wattage of ALL the brake lamps & see if the fuse is actually of a high enough rating? Be aware though that increasing the value of the fuse could cause damage elsewhere! As a rough guide a 25 watt bulb will pull around 2 amps at 12 volts - so 4 bulbs may pull up to 8 amps & clearly blow a 5 amp fuse! If in doubt take it to an auto electrician...... The wiring needs to be correctly protected!

The fuse box diagrams you are asking for are published in the 1998 Ford Windstar Owner's Guide starting on page 237.

If you do not have an Owner's Guide for your vehicle, you can download a free PDF version at the following link.

1998 Ford Windstar Owner's Guide

First thing to do is check the fuses. I believe the fuse for "Power Point 1" (the one in the instrument panel) is in slot 61 and Power Point 2 (the one in the center console) is in slot 64 of the fuse box which under the hood. The fuse box is located just in front and above the passenger front tire and the cover pops off easily. Check your owners guide (pages 190-194) to find the location of the fuses.The fuses in slots 61 and 64 are 20amp and should be yellow. Pull the fuses with a fuse puller and check to see that the two melal legs are connected inside the clear plastic with a ~ looking bar, if the ~ is broken then the fuse is bad. Replace the fuse with a new one (very inexpensive) and test the power point. If that dosent solve your problem then there may be something wrong with your cars electronics, consult a professional.

Sounds definitly like a fuse or a relay. If you have owners Manuel it will point out which fuse/ relay to replace. Remember, if a fuse blows there's a reason for it that needs to be remedied

you are going to have to look in your owners manual to tell us what fuse it is,

Not sure what you mean by eng mod fuse. What's the year, make and model? What's the description of that fuse in the owner's manual?

The dash power point fuse is # 39
The console power point is fuse #37

Note sure which fuse type you are talking about

The truck uses mini fuses & Maxi Cartridge fuses ( those are the ones that are at the end of the list.

http://www.genuineservice.com/genuineservice/en/default?page=genuineService

Go to this site and pick owner guide on left task bar. Input your vehicle info then pick get owner guide.Then pick owner guide 1st printing and your fuse info begins on page 104