Tow/haul fuse blowing

[macgyvr]

2008 F450 4x4 Dually Crewcab 6.4 54k miles.

I just picked this truck up last week. The tow/haul fuse is blowing. This fuse also controls the back up sensors, tcm, and 4x4 module. Also when the fuse blows I am getting a message on the display along the lines of "trailer brake wiring failure" or something close.

I replaced the fuse yesterday and drove it to my parents. Everything was working fine. I backed up to put some wood in the bed, after I started the truck back up, the fuse was blown and I got the trailer message.

I only get the trailer message when I hit the brakes.

I'm going to check the plug out today and see if there is anything obvious. I'm going to make my first tow this coming weekend and would really like to have tow/haul working as well as the 4x4 module. I could care less about the parking sensors.

thoughts or suggestions?

My assumption is that the two things are related...but I know that anything is possible.

I did buy the truck from a Ford Dealer, but since I didn't but a warranty doubt they will offer to do anything to fix the problem. I unfortunately have figured this out after signing the paperwork.

Also this truck has a plug in the bed for a fifth wheel or goose trailer plug in. Is this factory? I can't find any indications there was a fifth or goose installed from the previous owner, so I didn't know if the plug came installed or was installed.

mac 'so far everything else seems to work' gyvr

[macgyvr]

I did some checking today and it turns out that the fuse isn't blown. It is like sometimes the tow haul button wants to work and sometimes it doesn't. When the back up parking sensors come on they only work for about 5 seconds then automatically shut themselves off?

The only thing that I am for sure is working is I can hear the 4x4 motor moving the selector on the tcase...

mac 'suggestions before i visit my local dealer' gyvr

[macgyvr]

The truck is at the dealer where I purchased it in the hopes that since I bought it barely a week ago they will show me some love on the service bill...It is a Ford Dealer.

They tell me that one of the parking sensors is bad and that the trailer plug on the truck is corroded and that's what's causing the trailer brake wiring failure message. With the cost of the diagnosis fee they want $250.

They haven't been able to diagnosis the tow/haul switch not working yet. That scares me. I have no idea what they are going to come back and tell me that is going to cost. I told them not to fix anything until they know what is up with that so I know what the cost will be. I can buy and replace parking sensors I think and replace the trailer plug if needed, but the tow/haul issue is out of my realm of wreching.

I've done some searching and haven't really come up with anything on this forum for tow/haul issues on the trans (unless its buried in a long thread) so I'm playing it by ear to see what the dealer thinks.

I'll post the findings here for future reference.

mac 'love the idea of spending 34k to spend more' gyvr

[macgyvr]

I know that everyone has been sitting on the edge of their seat waiting to hear what the solutions to my problems were...

Well, the tow/haul, tcs was a ground strap that was broke, the parking sensors was a bad sensor, and the trailer plug was corroded. They fixed it all for the affordable price of $500. The sales dept, since I just bought it threw in $150, so I only paid $350. I was ok with it because it was missed in my test drive of the truck...and their oil change inspections as well...

All worked good, I towed my single place trailer with a jeep, this past weekend (total weight of trailer under 7k) 300 miles and got 8.9 mpg...i'm hoping the 14k of an enclosed with two jeeps will get close to 8 mpg.

mac '4.88 gears' gyvr