ABS indicator light on Trailer
 

Yesterday one of our other drivers was pulled over and given a Level I DOT Inspection. The only thing they found and wrote him up for was the ABS Indicator light on the trailer did not light up when the truck was not running and key was in the "on" position.

Has anyone heard of this requirement and especially can anyone post/quote the reg that covers it? I have never heard of it, and checked my truck/trailer and it does not come on. We checked 3 others in the yard and none of them come on when the key is turned on either.

BTW, Jackrabbit, this was just west of Holliday on 277 so beware!

Sounds like someone needs to change some bulbs.............


Part 571: Motor Carrier Vehicle Safety Standards



S5.1.6.2 Antilock malfunction signal and circuit.

(a) Each truck tractor manufactured on or after March 1, 1997, and each single unit vehicle manufactured on or after March 1, 1998, shall be equipped with an indicator lamp, mounted in front of and in clear view of the driver, which is activated whenever there is a malfunction that affects the generation or transmission of response or control signals in the vehicle’s antilock brake system. The indicator lamp shall remain activated as long as such a malfunction exists, whenever the ignition (start) switch is in the ”on” (”run”) position, whether or not the engine is running. Each message about the existence of such a malfunction shall be stored in the antilock brake system after the ignition switch is turned to the “off” position and automatically reactivated when the ignition switch is again turned to the “on” (”run”) position. The indicator lamp shall also be activated as a check of lamp function whenever the ignition is turned to the “on” (”run”) position. The indicator lamp shall be deactivated at the end of the check of lamp function unless there is a malfunction or a message about a malfunction that existed when the key switch was last turned to the “off” position.




(b) Each truck tractor manufactured on or after March 1, 2001, and each single unit vehicle manufactured on or after March 1, 2001, that is equipped to tow another air-braked vehicle, shall be equipped with an electrical circuit that is capable of transmitting a malfunction signal from the antilock brake system(s) on one or more towed vehicle(s) (e.g., trailer(s) and dolly(ies)) to the trailer ABS malfunction lamp in the cab of the towing vehicle, and shall have the means for connection of this electrical circuit to the towed vehicle. Each such truck tractor and single unit vehicle shall also be equipped with an indicator lamp, separate from the lamp required in S5.1.6.2(a), mounted in front of and in clear view of the driver, which is activated whenever the malfunction signal circuit described above receives a signal indicating an ABS malfunction on one or more towed vehicle(s). The indicator lamp shall remain activated as long as an ABS malfunction signal from one or more towed vehicle(s) is present, whenever the ignition (start) switch is in the “on” (”run”) position, whether or not the engine is running. The indicator lamp shall also be activated as a check of lamp function whenever the ignition is turned to the ”on” (”run”) position. The indicator lamp shall be deactivated at the end of the check of lamp function unless a trailer ABS malfunction signal is present.





S5.2.3.3 Antilock malfunction indicator.

(a) In addition to the requirements of S5.2.3.2, each trailer and trailer converter dolly manufactured on or after March 1, 1998, and before March 1, 2009, shall be equipped with an external antilock malfunction indicator lamp that meets the requirements of S5.2.3.3 (b) through (d).

(d) The lamp shall be illuminated whenever power is supplied to the antilock brake system and there is a malfunction that affects the generation or transmission of response or control signals in the trailer’s antilock brake system. The lamp shall remain illuminated as long as such a malfunction exists and power is supplied to the antilock brake system. Each message about the existence of such a malfunction shall be stored in the antilock brake system whenever power is no longer supplied to the system. The lamp shall be automatically reactivated when power is again supplied to the trailer’s antilock brake system. The lamp shall also be activated as a check of lamp function whenever power is first supplied to the antilock brake system and the vehicle is stationary. The lamp shall be deactivated at the end of the check of lamp function, unless there is a malfunction or a message about a malfunction that existed when power was last supplied to the antilock brake system.

PTD is correct.

It may be that the bulb is burnt out....but also, when hooking to a trailer....if the ABS light on the trailer does not come on when the key is turned "on"....pry the bulb gizmo out and make sure that plug on the rear is properly attached. If it isn't, connect it and repeat the key on.

If the light stays on...it indicates that the ABS system needs service. It could be as simple as a dirty sensor, or one that has been knocked out of position.

This happened to a good friend of mine. He got written up by DOT for the same thing. He said the light wasn't on when he did his pre-trip. He got stopped at a scale, and the light was on then.

We have some newer Stoughton and Wabash trailers that have the abs light on the rear corner of the trailer, on the driver side. The light only comes on when there is a problem with the trailer abs. I have never seen the light come on while turning the key. According to the manufacturer, the trailer abs light will only come on, and stay on, when there is a trailer abs problem.

The light should come on for 2 seconds as a bulb check when power is applied to the auxiliary pin of the trailer. Most trucks do that any time the key is on but I have come across a few trucks with a manual on/off switch.

If there is no power to the AUX wire then the ABS light will come on when the brakes are pressed, power backfeeds into the module.

I got a roadside Level II in Alabama last week and the officer asked me..."Uhhh...whats that green line for?"

So what is the green line for?

aint the green line the train that goes to brooklyn? :lol2: