12 Volts in Back

[Doggy-Dog]

Anybody know of where I can find 12 volts in the back of the truck by the bumper? This would be switch on and off with the ignition. Also not connected to the trailer connector.

Sponsored

 

[BLoflin]

Why not the trailer connector? Pin 4 is 12V (and on a 30A fuse) and only on with ignition and pretty easy to get to the backside of the connector to tie on to.

Also, you have to be kind of careful where you might put a random load on a 12V source wire as the truck has become very "smart" in monitoring loads and current draws on many of the circuits (looking for fault conditions like opens and shorts, lights burned out, broken).

In the old days any wire that was hot (12V) was good to use for aftermarket up until blowing the fuse. Now, you have to be more careful.

 

[Doggy-Dog]

I know exactly what you mentioned. Any load on that trailer connector and the alarms go off telling you there is a trailer connected and your safety stuff is disconnected. The load I would be using is about 100 mA. Guess I will try that and see what happens
That is why you had to use resistors in my 2019 when installing LED bulbs. The system had a fit when the old bulb was not sucking a ton of juice.

 

[BLoflin]

I know exactly what you mentioned. Any load on that trailer connector and the alarms go off telling you there is a trailer connected and your safety stuff is disconnected. The load I would be using is about 100 mA. Guess I will try that and see what happens
That is why you had to use resistors in my 2019 when installing LED bulbs. The system had a fit when the old bulb was not sucking a ton of juice.

With just 100mA load, I guess you might be good anywhere.

On the 12V on the 7 pin, I think (but don't know for sure) that is Not monitored for any conditions (besides the 30A fuse for overload/shorts). There is no requirement that a trailer has to connect anything to that pin. So with or without a trailer connected, that pin could see 0 load or any amount (depending on what, if anything, it is hooked to in the trailer) up to 30A.

 

[Doggy-Dog]

Well, that reads as interesting. It snowed again here so the truck is wet and so is the garage floor. After going to my doctor on Tuesday, I will be able to leave truck in garage and let it and the floor dry up. So I will look into that 12 volt wire in a couple of days.
Thanks.

 

[Doggy-Dog]

Well, things dried up faster with the Sun showing and I went checking. With ignition on-nothing. With the engine running-nothing. No 12 volts on any pin at the trailer hitch. If it should be there then Ford must have forgot to hook it up. Will check the fuse box on Wednesday. Too late to play with it today.
Bummer.

 

[BLoflin]

That's strange. Across pin 4 (12V) and pin 1 (Gnd) with a DC Voltmeter you should see 12V when truck is on.

 

[Doggy-Dog]

Nice picture of the connector. I was so curious to check it out I went to my 45 degree garage and turned on the truck and stuck the meter probes in the connector. Results-DEAD. No reading. So Wednesday after turning up the heat I will check and see if Ford forgot to install a fuse.

 

[BLoflin]

That's the Under Hood Fuse Box from pg 473 of my Owners Manual, just upside down. I attached a rotated version of it, so it's easier to see.

So fuse 107 from diagram which is one of the pink colored ones that is 30Amps in your pic. So yes you have it installed.

 

[Doggy-Dog]

Yes, I discovered that rotation problem. I also found a post on another site that just may answer the entire problem of zero volts on that 12 volt pin. Below is what that person stated.
Guess I will have to find 12 volts somewhere else.
.

 

[BLoflin]

Yes, I discovered that rotation problem. I also found a post on another site that just may answer the entire problem of zero volts on that 12 volt pin. Below is what that person stated.
Guess I will have to find 12 volts somewhere else.
.

Don't know why/how those things are said....

Anyway, I just jumped up and went out and measured again, for ya.

No trailer (truck is in my garage).

Sitting there off = no voltage (as expected)

Truck On (accessory mode, not running) = 12.8V

Truck Running (fully on) = 12.8V

Turn Truck back off = no voltage.

 

[Doggy-Dog]

I even checked the fuse today and no problem with the fuse. Still nothing at that trailer connector. On or off-zero volts. Thursday I am going to jumper on a couple of lights so the truck will think a trailer is attached and see if I get volts then. If still none, then Ford must have messed up the wires on my truck.

 

[BLoflin]

In case you didn't yet.... Did you check the fuse after you pulled it with an Ohm Meter (it should show 0 ohms)? Also, you could (carefully) probe the fuse holder contacts (with the fuse out) in the fuse box to see if you are getting 12V on one of the contact sides.

 

[Doggy-Dog]

In case you didn't yet.... Did you check the fuse after you pulled it with an Ohm Meter (it should show 0 ohms)? Also, you could (carefully) probe the fuse holder contacts (with the fuse out) in the fuse box to see if you are getting 12V on one of the contact sides.

That is a good idea. I should have the other day when I checked the fuse. Fuse is OK. I will pull it again maybe Monday when we will see a little warm up and check there for 12V. Still going to try the "fake the truck" in thinking there is a trailer connected to see if that turns on the 12V pin.

 

[Doggy-Dog]

It got up to 50 today! WOW! So I went out and connected some trailer lights with jumpers to the trailer connector and started the truck. Notice on display that all the safety stuff was disconnected because a trailer was connected. Put my meter probes on pin 1 and 4 an sure enough there was 12 volts. Shut off the truck and removed the fake trailer light connection and went back and started the truck. Notice on display trailer was disconnected. Went out and checked pins 1 & 4 and no voltage. Zero, nothing. So who ever stated that 12 volts comes on when a trailer is connected was 100% correct. But this may be different with your unit. Or YUMV=your unit may vary.

Sponsored