I have had my ABS light come on twice on my 97 F250 in the last 3 months and it locks it in park. Both times it was when I was pulling my boat. I found a blown fuse both times. The first time i Unplugged both of the factory trailer harness's and only plugged the 4 wire back in and it has worked fine until this week. I drove 900 miles with my boat and two days later it did it again. I found a blown fuse again. I unhooked all of the wire harness's and put in a new fuse and it worked until the nest morning. That time I hit the overdrive button 3 times and it went off. I just drove 900 miles back home and it worked fine. What is the cause of this?

 

Welcome to FTE.

What do you mean both harnesses?
What fuse is popping?
Do you have electric brakes on the trailer?
How many wires are going to the trailer?
Are you disconnecting the trailer when you dunk it in the water?

If you have no trouble with the trailer disconnected look for a short in the trailer.

 

I unhooked the two plugs. One is the 4 wire for lights/stops/turns/ground the other one is for the trailer brakes which i left unhooked after the first time it happened. I always unhook the trailer plug before backing in the water. The fuse was the #13 possition fuse which is the stop/hazard-anti-lock brakes-speed control-stop sense for electronic engine control-automatic transmission shift interlock fuse.

 

Did you have the cruise control on when this happened. If so, check the BPA (Brake Pedal Applied) switch on the end of the master cylinder. Remove the plug and look for brake fluid in the cavity. The BPA is a normally closed (continuity all the time) it opens when the brake pedal is applied.
BTW: the BPA has been the subject of a re-call due to shorting out and starting fires. This is not a concern for diesels but it's still the same switch.....with the same failure. You might get a new one for free from the dealer.

 

I did not have the cruse on. Both times I pulled in to get the boat ready and when I started it back up and hit the brake pedal to put it into gear the ABS light came on and it would not come out of park. The first time it happened I unplugged the 4 wire and 3 wire harness going to my trailer plug and replaced the fuse and it worked for 2 months and did not have a problem until last week.

 

Let's hope the new BPA solves your intermittent problem. Time will tell.
You could check your brake lights too for corroded light sockets...especially the 3rd brake light on the cab.

 

Yea, it sounds like something actuated with the brake.

The wiring harness shoudlnt' blow that fuse.

It wont come out of park because it thinks the truck's brake is not pushed in.