I agree with Tim and Mark K....It could be the Multifunction switch in the steering column. However, early Gen-1 Sport Trac's had a problem with the tilt steering wheel pulling on the wiring harness and either pulling wires out of the connector, or breaking wires. Moving the tilt wheel up and down would cause various wires to connect or disconnect. The Multi-function switch controls everything going through the steering column including ignition, starter, headlights, turn signals and taillights, horn, wipers, cruise control, and probably a few more things that I can't remember now. :grin:
The cure is to check the connector under the steering column to verify that there is sufficient slack in the wiring harness to allow for the full range of tilt without pulling on the wires. You can simply pull up more slack in the wiring harness, but be sure that none of the wires are broken or pulled out of the connectors.
If that does not resolve your problem, then you may have a bad Multifunction switch......which is a bigger project than simply checking for bad connections due to the tilt wheel.
...Rich