1989 Ford Bronco Owner's Manual - Page 189
1989 Ford Bronco Manual
Page 189 highlights
Tires, Wheels and Loading 6. If the trailer wheels lock-up (indicated by squealing tires), reduce the GAIN setting; if the trailer wheels turn freely, increase the GAIN setting. Repeat Steps 5 and 6 until the GAIN setting is at a point just below trailer wheel lock-up. If towing a heavier trailer, trailer wheel lockup may not be attainable even with the maximum GAIN setting of 10. Explanation of instrument cluster warning messages: The TBC interacts with the instrument cluster message center to display the following messages: TRAILER BRAKE MODULE FAULT: This message is displayed and accompanied by a single chime, in response to faults sensed by the TBC. In the event this message is seen, please contact your authorized dealer as soon as possible for diagnosis and repair. The TBC may still function, but performance may be degraded. WIRING FAULT ON TRAILER: This message is displayed when a Short circuit on the electric brake output wire has occurred. If the WIRING FAULT ON TRAILER message is displayed and accompanied by a single chime, with no trailer connected, the problem is with the vehicle wiring from the TBC to the 7-pin connector in the bumper. If the message is only displayed with a trailer connected, the problem is related to the trailer wiring; consult your trailer dealer for assistance. This can be a short to ground (i.e., chaffed wire) or a short to voltage (i.e., pulled pin on trailer emergency break-away battery) or trailer brakes drawing too much current. Note: Your TBC can be diagnosed by your authorized dealer to determine exactly which trailer fault has occurred; however, if the fault is with the trailer this diagnosis is not covered under your Ford warranty. Points to Remember: • Remember to adjust gain setting before using the TBC for the first time. • Readjust GAIN setting on the TBC (according to procedure above) whenever road, weather and trailer or vehicle loading conditions change from those that existed when the gain was initially set. • The sliding lever on the TBC should be used only for manual activation of trailer brakes to assist with proper adjustment of the GAIN. Misuse, such as application during trailer sway, could cause instability of trailer and/or tow vehicle. • Avoid towing in adverse weather conditions. The TBC does not provide anti-lock control of the trailer wheels. Trailer wheels can lock-up on slippery surfaces, resulting in reduced stability of trailer and tow vehicle. 189 2010 Econoline (eco) Owners Guide, 3rd Printing USA (fus)