The trailer malfunction light will join the existing red ABS light, which indicates a malfunction in the tractor's ABS, on the instrument panel when the rule becomes effective in 2001. The current trailer ABS malfunction light is installed on the lower-left side of the trailer, near the axles. If the amber warning light glows, the driver can spot it in his side-view mirror. This can be used until 2008. ABS became mandatory on air-braked trailers March 1 and on tractors last year.
Older ABS gets power from the brake light circuit and only when the driver steps on the brake pedal.
Navistar International Transportation Corp. He is one of nine members of a Truck Manufacturers Assn. Others are from Freightliner, Mack, Paccar and Volvo. However, the accessory circuit is already used by some truck operators to power and activate lights, pumps, lift gates and other devices on the trailer. They may have to stop using the accessory circuit and begin using a separate wire and connector between tractor and trailer, said Messrs. Gemander, Menig and Hammes. Other options include a special pneumatic-electrical switch that operates the accessory while the trailer is parked and its brakes are locked.