Well i dug through a ton of old posts and can't find anything on this.

I just bought a 05' F-150 with factory installed trailer/tow package. I pull a 7x14 enclosed trailer that worked great with my 02' 250......my issue is now when I am driving down the road at night with the lights on the cruise keeps shuting off......sometimes it does it on its own, other times when I hit the turn signal it shuts off the cruise.

Anyone have any experience on this??? What a pain in the butt since I pull that trailer 10,000 miles a year....mostly interstate where the cruise is nice to have.

 

Do you have the OD on or off when this happens.

Could be the truck cannot maintain speed in OD, and is signaling a problem due to using OD when towing ? The 04+ are all throttle by wire now, and quite a bit has changed.

 

Hi I would think to try driving the truck without the trailer and see if the same happens..... If not, I would guess the problem may be in the trailer wiring harness. Since you said it happens when you put the turn signal on, or have the lights on somehow I think you are getting a cross feed to the brake light circut from the trailer/truck harness. Just an Idea to check out since i have seen it happen before on a friends chevy.

 

Make sure you have a good ground from the trailer to the truck. Don't rely on the hitch to ground the trailer, use a ground wire going through the plug and ensure that it's connection to the truck frame and trailer frame are clean and tight. A weak or intermittent ground can cause voltage from one circuit to feed back in on another causing strange things to happen.

 

x2

Pull a new ground wire from the trailer's connector all the way back to BOTH taillights.

 

Sounds good, thanks guys. Probably have to add a ground wire, it has never grounded real well since the ball is usually rusty and it takes a few miles to get a good connection......but I never had a problem with my 02' powerstroke.......seems odd they would tie the crusie into the lights???

 

I'll have to admit I don't know why this would be a good suggestions.

The trailer ground is via the 4 pin flat, or 7 pin round trailer plug.

To have a bad ground on this would put it at the plug itself, as the same ground for the tail lights and the trailer tow adapter are up on the driver's side frame rail, about where the spare tire is at.

As for a ground causing the problem, I guess the with and without the trailer using the CC might be a good place to start ??

Additionally, the lights for the trailer, are isolated by relays on the truck.
This would mean a ground problem is feeding back through the trailer harness on the truck, feeding through a Normally Open contact on the trailer tow relays, back through the +12 V power dist buss, and feeding back trough the fuse to the CC ??