99 windstar tail lights and headlights come on by there self no switch turned on

Check the wiring to that socket. Possibly a wire broke or bad bulb socket. The license plate light is only a splice from the tail light wires, so if both or all tail lights work from the park/headlight switch, the tag light problem is right there at the rear. If you have a voltmeter or a test light, check for power to the bulb socket with the park lights on.

have you checked your fuses

You have a short in your daytime runnig lights

No. All those lights are on the same fuse and are controlled by the headlamp switch.

Make sure that the fuses were all checked on the fuse panel inside the vehicle under the dash. That is where the fuse for those lights is.

The relay has nothing to do with the tail lights, but replacing the switch sounds like a good idea. There's a nut holding it in place, see http://www.skandix.de/en/spare-parts/electrics/switches/switch-headlight/1027524/ to get an idea of the construction. And the price. This is not worth fiddling about unreliable workarounds...
In addition, if fuses 15 and/or 16 burn frequently there might be a problem with the tail light cabling.

Good luck
Ingo

bad or lose connection at the headlight switch or bad switch

the headlight switch may have a short in it. replace switch and try again.

WHAT YOU MIGHT CHECK IS THE FUSE FOR TAILLIGHTS, OR DASH LIGHTS. THEY WORK OFF THE SAME FUSE. IF THE FUSE IS BLOWN THE HEADLIGHTS WORK BUT NO TAIL OR DASH LIGHTS

relay? or the switch it self mine had that problem but the headlights didnt work

you could have a broken wire for your tail lights or the wiring harness for taillights is grounding out