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Tim Mohr
Tim Mohr, ASE MASTER TECH
Category: Ford
Satisfied Customers: 15412
Experience:  30 YRS EXPERIENCE, FOREIGN AND DOMESTIC, GAS AND DEISEL
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I have a 2009 f350 was pulling camper and all lights worked

Customer Question

i have a 2009 f350 was pulling camper and all lights worked one day the next day my running lights went out I have blinker, break and backup lights and power brakes work where can i look I have checked all fuses and they are good checked relays and pretty sure they are good
Submitted: 1 year ago.
Category: Ford
Expert:  Tim Mohr replied 1 year ago.

Hi, my name is ***** ***** these the running lights on the camper or on the truck?

Customer: replied 1 year ago.
on camper only i have them on the truck
Expert:  Tim Mohr replied 1 year ago.

ok,the towing lights have their own fuses and relays, seperate from the truck, do you have a test light or a voltmeter? I an help you diagnose this?

Customer: replied 1 year ago.
i have a test light
Expert:  Tim Mohr replied 1 year ago.

that will work, first off, in the fuse box under the hood, we need to check fuse F42, and see if it has power, when the lights are on?

Customer: replied 1 year ago.
i do
Expert:  Tim Mohr replied 1 year ago.

and there is power on both sides of that fuse?

Customer: replied 1 year ago.
Expert:  Tim Mohr replied 1 year ago.

ok, in the same fuse box, there will be a relay marked "trailer tow/ parking lights" can you locate this relay and remove it?

Customer: replied 1 year ago.
it says trailer tow park lamps #55
Expert:  Tim Mohr replied 1 year ago.

yes, now on the bottom of the relay, there will be numbers stamped into the plastic, identifying each pin, they will be 30, 85, 86 and 87, do you see these numbers?

Customer: replied 1 year ago.
i see these numbers
Expert:  Tim Mohr replied 1 year ago.

ok, in the socket the relay plugs into, we need to see if #30 has power at all times, and if 85 has power when the lights are on

Customer: replied 1 year ago.
30 has power at all times but 85 has no power with the key off and lights on but has power all the time with key on
Expert:  Tim Mohr replied 1 year ago.

ok,can you jumper 30 and 87, and see if the trailer lights go on?

Customer: replied 1 year ago.
did it and got nothing
Expert:  Tim Mohr replied 1 year ago.

ok, can you check the brown wire at the towing connector, on the truck side, with it jumpered? disconnect the trailer and check it there

Customer: replied 1 year ago.
still nothing
Expert:  Tim Mohr replied 1 year ago.

so there is no power to the brown wire, at the trailer connector when the 87 and 30 are jumped?

Customer: replied 1 year ago.
that is correct
Expert:  Tim Mohr replied 1 year ago.

ok, then the brown wire is broken, somewhere between the fuse box and the trailer connector, I would start at the trailer connector and trace it back, to find the break,Tim

Customer: replied 1 year ago.
but didn't you say that 85 needed to have power when the lights were on? mine has power all the time when the key is on and nothing when the key is off it makes no difference weather the lights are on or off
Expert:  Tim Mohr replied 1 year ago.

on this, it will have power anytime the parking lights are on, and they come on with the key on this model, when power is applied to the 85, the relay closes and puts power from the 30 to the 87, which power the brown wire at the trailer connecor, since you jumpered the 30 to the 87, you have taken the relayb and everything else out of the system, if the brown wire st the trailer connector does not have ower when jumping 30 to 87, then it can only be a broken wire between the fuse box and the connector, nothing else,Tim

Customer: replied 1 year ago.
we were told that the ........panel where all the fuses and relay switches plug into was out what is you idea on that
Expert:  Tim Mohr replied 1 year ago.

it could be, you need to check the brown wire at the fuse box, and see if it has power with the relay jumpred, if it does, then the wire is broke, if it does not have power, then its in the fuse box it self,Tim

Customer: replied 1 year ago.
ok thanks
Expert:  Tim Mohr replied 1 year ago.

Anytime my friend, Please dont forget to rate me so I cn get credit for helping,Thanks,Tim