abs check lights

The trailer light should come on momentarily when you first power up, I have had to change a few bulbs on these, you wouldn't think that any more than they work. Just remember that it must have ABS on the lense if you replace it, they will write you up on a DOT inspection if it doesn't come on with the clearance lights if it isn't marked.

 

Good info above. I have a 2002 truck with a 2010 trailer and that is how its supposed to work but it doesnt always do the check cycle when you turn the key off. What I mean by this is I can have the truck running, turn it off and then start it up again and sometimes it doesnt go thru this cycle. Whats bad about this is that if during a roadside inspection (has happened to me) that they have you do this and it doesnt work then you will get a bonus surprise of 12 CSA pts + warning/fix it ticket and have to take it to a mechanic to have it verified that it is working. That cost money and time(which is more money lost) and then make endless phone calls (more time which equals money lost) to try and get the 12 pts removed that shouldnt be there in the first place.

 

These are good points, having recently checked several carriers CSA Records I am seeing more and more violations noted during a DOT inspection where the abs system wasn't working properly and the companies assessed accordingly. They had noted the in cab warning light for the abs system as well. What I find astonishing about that is that I never seem to see any of the abs systems that work much more than a year or two, I guess this is just another government mandate that requires you to have a man running along behind you with the tool box in hand. I have NEVER had the abs systems do anything for me other than be a nuisance. The industry fought that off once, then it came around again and the second time no one fought it. Do we now "not pull the trailer", (write up and put out of service during pretrip), because the abs system is not indicating that it works during pretrip, how long is that going to last?? What percentage of trailers in any given yard are the abs systems actually working on??

 

ABS malfunctions are the wheel sensor 90% of the time. What happens is the tire guys will pull the tires off, change out the blown tire, remount, but never verify the sensor is back in place. When a tire blows, your bearing end play will adjust from the sever movement and it will tap the sensor just slightly. Dismounting and remounting the tires during your inspections can occasionally cause that as well.

Another are to look at, the front of the spring for your lines has a small plug. That is the ABS module plug. Remove it, put some dielectric grease there and plug back in. They tend to get a little loose when you have to slide the tandems back for loading.

Most of your ABS problems, I can find and solve in minutes.

Oh, another thing to do, spread the center pin slightly on 7 way box. It gets the most movement from where it is located. That solves a lot of ABS issues.

 

Last year I pulled a 2002 rented trailer for a while. The ABS light would come on anytime the brakes were applied. (like a brake stop light). Does this mean there was a problem with the system on the trailer?

 

The light should come when you make a brake application. I think if you held down on the brakes, after a second or two the light would go out. If it stays on then I believe that would indicate a problem.

 

The only time you should see the abs light on the side of the trailer come on is for a few seconds after powering up, (sending electric current to the trailer through the power cord, any time the key in the tractor is "on" there will be current supplied to the trailer), any other time that you see this light on would indicate a problem. The abs light on the dash of the tractor I have seen come on while sitting on occasion, (while pumping a load off for example), but the moment that you start rolling it will go off if every thing is working properly. I don't know the reason for the dashlight doing this, but I have wondered if you were in the process of a DOT inspection when this happened, would the officer see this and write you up? I guess it is time to get educated on the abs systems to be sure.

 

This is only true with newer trucks. The older ones don't have ignition power for trailer ABS on the center pin. In that case the trailer ABS light would only come on when the brakes are applied. The trailer ABS module will always work off of brake light power as a safety back up should either the constant power fail, or the trailer is connected to an older truck without the center pin constantly powered.

 

I remember when they started powering the center pin, seems like around 1996, but I could be way off there. Are you talking about the original abs brakes that were introduced and then done away with or are you talking about the second round up to around 96, I can remember a few of the ones that you are talking about, but I can't get it out of the archives.