Trailer ABS

really ABS unit is constantly powered (with 5/7 pin cabel in EU and with central pin on US trailers).

brake light ABS power is used as redundance.

the first we must start looking for TABS problems is to identify system. We do not know what the ABS unit installed on this trailer

 

ABS does require 12v ignition power to work properly. The stop light power is a trigger for the ABS ECM. It does act as a fail safe power supply. If there is no 12v ignition power on the blue wire the moment you apply brake the ABS will turn on and start to do its valve checks. This takes about 3sec. So in a panic stop you probably would not have ABS from the moment you hit the brakes. The manufactures state ABS must have 12v ignition source. haldex and Wabco. Also if you are troubleshooting abs faults you need to cycle 12v blue wire power while having 12v stop light power applied. Hope this helps. We rewired all our Trucks to have 12v ignition power on 7wire blue lead. Solved all problems.

 

Yes, you are right. The guy just wanted to know if he can pull this trailer and if the abs will work, and yes it will. Yes it will have a delay, I mentioned that in an earlier post. If the OP wants to rewire his truck, then fine. He is asking if he has to, and I say no. If he wants it to work at its optimal performance, than yes he needs to wire up the center pin. I was just giving him the information, now he can make his own decision.