ABS With Older Tractors

ABS computer gets power from stop light signal circuit. When you push brake pedal ABS light will blink.

 

Older trucks sometimes used the seventh pin for other stuff, does this particular trailer have constant power to the center pin?

If not then yes, ABS will power up any time you hit the brakes and the light on the trailer will come on when you hit the brakes, then shut back off.

 

It's also supposed to blink a couple of times when the key is turned on.

MT gave me a fix it ticket a few years back. Because it didn't blink.

 

Correct. A modem trailer, when the abs powers up, will turn the light on for about two seconds. This lets you know that the malfunction light is working, that it hasn't simply been disconnected, and that it is getting power. If it is working but isn't getting power, then that cycle happens every time you hit the brakes, because it will get power from the brake wire.

 

Should be, yes. I'd double check to make sure when you power on the truck the abs light comes on for a second or two then turns off, and someone standing towards the back of the trailer should hear the abs actuators cycle on and off. Just sounds like clicking. But yes if you have power to that pin then an abs trailer should function properly.

 

I regularly pull a 2016 ABS trailer with a 1995 non-ABS truck. Only thing you have to do is to make sure your center pigtail pin is 12v off the ignition. The truck originally had a dead center pin, All I had to do was hook it to the keyed ignition inside the breaker box.

 

Yes, but if it's not on the ignition, you'll be sending power to the ABS all the time with the trailer hooked up, and it will run the battery down when parked. It could get you by in a pinch, you'd just have to remember to unplug you pigtail when parked, and it could get you a violation. If you get an inspection, and they have you run the ABS test, they will want to see the light cycle. Short of unplugging the pigtail, you'll have no way to cycle the ABS and prove that your fault light is working.

On most trucks I've dealt with, the trailer pigtail wiring terminates at the breaker/fuse box. It would be easy enough to swap that one wire from constant 12v to ignition 12v.