Bronco II 4WD V6-171 2.8L (1985)
Fig. 7 Speed control wiring diagram. 1986---87 Aerostar
1983-87 Ranger, 1984-87 Bronco II & 1986-87 Aerostar
1.
Locate horn relay connector yellow wire w/light blue dots, then using a suitable voltmeter, check voltage from relay connector wire to ground,
Figs. 6 and 7. Horn relay connector should remain connected during this test.
2.
If 12 volts are not present in step 1, check fuse and/or repair circuit. If 12 volts are present in step 1, depress horn switch.
3.
Voltage should drop to approximately 0 volts and horn should sound. If 12 volts are present when horn switch is depressed, switch is defective and
should be replaced.
4.
Check relay operation by grounding relay terminal number 2 and bypassing the horn switch. If voltage is present on horn relay yellow wire w/light
blue dots but not on relay terminal 2, horn relay is defective and should be replaced. If 12 volts are present at horn relay terminal, proceed to step
