1998 Ford F150 Tow Hitch Wiring Diagram

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1998 F150 4x4 trailer brakes., wanting to add them

hgoody77: New Member; Posts: 20; Joined: Fri Feb 20, 2009 4:46 pm; Location: Bartlett, Tn ( Memphis ); My Truck Mods

1998 F150 4x4 trailer brakes., wanting to add them

Hi, i am wanting to add a brake controller to my truck, it has a 4 way plug but i need the big round plug in the back with trailer brake controller in the cab. can i just buy any brake controller and splice into wires under the dash? what other 3 wires do i need to get to the hitch and were do i need to run wire from to get a total of 7 back there to the hitch. will the vin tell me if it had a tow package?
thanks, Howard

RkyMtnHi: Hardcore Ford Truck Fanatic; Posts: 4596; Joined: Sat Aug 21, 2004 6:58 pm; Truck: 1999 F-150 4X4 -5.4; Location: Denver, Colorado; My Truck Mods

Post by RkyMtnHi » Fri Feb 20, 2009 8:21 pm

The pigtail for the 7 wire plug is available at the Ford dealer. To install it you drop the spare tire and plug it into the connector you will find there, and mount the other end to the bumper. I have the Trailer Tow Package wiring schematics which shows all the wires, fuses and connections. If you want to send me your email address in a Private Message, I will send them to you.

hgoody77: New Member; Posts: 20; Joined: Fri Feb 20, 2009 4:46 pm; Location: Bartlett, Tn ( Memphis ); My Truck Mods

Post by hgoody77 » Sat Feb 21, 2009 1:46 pm

ok thanks for the prints, So if the truck does not have the tow package, and mine does not. what wires do i tap into under the dash?

RkyMtnHi: Hardcore Ford Truck Fanatic; Posts: 4596; Joined: Sat Aug 21, 2004 6:58 pm; Truck: 1999 F-150 4X4 -5.4; Location: Denver, Colorado; My Truck Mods

Post by RkyMtnHi » Sat Feb 21, 2009 2:21 pm

Did you check to see if there is a connector above the spare tire to plug the 7 pin plug into? I think there should be.

If there is not a connector there, look at page 5. It identifies all the wire colors.

hgoody77: New Member; Posts: 20; Joined: Fri Feb 20, 2009 4:46 pm; Location: Bartlett, Tn ( Memphis ); My Truck Mods

Post by hgoody77 » Sat Feb 21, 2009 2:35 pm

connector at rear spare tire. from what i read, the adapter would be round if it was able to run the trailer brake controller. otherwise i have to run more wires back there as i understand it.
in this PDF file in the figure #4 it says hook that red wire from the brake controller to the non-powered stop light wire. is that the wire that is "LG-light green" on your prints that is on page 5?

http://www.hayesbc.com/PDFs/[email protected]%2 ... 21-CAB.pdf

RkyMtnHi: Hardcore Ford Truck Fanatic; Posts: 4596; Joined: Sat Aug 21, 2004 6:58 pm; Truck: 1999 F-150 4X4 -5.4; Location: Denver, Colorado; My Truck Mods

Post by RkyMtnHi » Sat Feb 21, 2009 2:43 pm

I have never wired a brake controller, but the instructions on page 3 seem to me to be fairly straight forward, unless your controller is set up differently from the wiring on the truck.

From what it says, no additional wiring should be necessary.

RkyMtnHi: Hardcore Ford Truck Fanatic; Posts: 4596; Joined: Sat Aug 21, 2004 6:58 pm; Truck: 1999 F-150 4X4 -5.4; Location: Denver, Colorado; My Truck Mods

Post by RkyMtnHi » Sat Feb 21, 2009 2:47 pm

You may need to purchase the Jumper Harness they mention. It has a part number.

hgoody77: New Member; Posts: 20; Joined: Fri Feb 20, 2009 4:46 pm; Location: Bartlett, Tn ( Memphis ); My Truck Mods

Post by hgoody77 » Sat Feb 21, 2009 3:02 pm

ok, so i got under there and i did in fact find a 6 way grey plug in under the dash. took a little diggin, i aint the smallest fella, ha ha it's a tight fit to get under there and look around. so im thinking i can put the brake controller in with a harness to connect to that grey plug.

RkyMtnHi: Hardcore Ford Truck Fanatic; Posts: 4596; Joined: Sat Aug 21, 2004 6:58 pm; Truck: 1999 F-150 4X4 -5.4; Location: Denver, Colorado; My Truck Mods

Post by RkyMtnHi » Sat Feb 21, 2009 3:05 pm

That is the way I read Page 3 and the controller installation pdf. You just wire the appropriate wire colors from the controller to the loose wires on the plug.

hgoody77: New Member; Posts: 20; Joined: Fri Feb 20, 2009 4:46 pm; Location: Bartlett, Tn ( Memphis ); My Truck Mods

Post by hgoody77 » Sat Feb 21, 2009 3:05 pm

well, so do all the trucks come with this 6 way connector? i asked the dealer about a tow package and he told me no according to the vin number. about to go drop the spare tire and see what plug in i have back there. there is a 4 pin trailer plug at the hitch already.

hgoody77: New Member; Posts: 20; Joined: Fri Feb 20, 2009 4:46 pm; Location: Bartlett, Tn ( Memphis ); My Truck Mods

Post by hgoody77 » Sat Feb 21, 2009 3:22 pm

the plug i have out back by the spare tire is a 12 wire plug square in shape.

RkyMtnHi: Hardcore Ford Truck Fanatic; Posts: 4596; Joined: Sat Aug 21, 2004 6:58 pm; Truck: 1999 F-150 4X4 -5.4; Location: Denver, Colorado; My Truck Mods

Post by RkyMtnHi » Sat Feb 21, 2009 3:29 pm

Look at the pigtail on page 2 and see if it looks like it will plug into the connector you are looking at.

hgoody77: New Member; Posts: 20; Joined: Fri Feb 20, 2009 4:46 pm; Location: Bartlett, Tn ( Memphis ); My Truck Mods

Post by hgoody77 » Sat Feb 21, 2009 4:10 pm

hummm, yeah. i guess i could assume that it would fit. i mean it's square. whats the round plug for?

Well, i was going to get a brake controller and an adapter for the plug under the dash, i will need them anyways. seems like everything is correct to me. i dunno. i got the grey 6 way connector under the dash for the brake controller, and heck there is 12 wires out back at the spare tire, to me it looks like i need that ford, or equivelant, wire harness from the plug i at the spare tire to a new 7 way RV trailer plug outlet. does that seem correct?

RkyMtnHi: Hardcore Ford Truck Fanatic; Posts: 4596; Joined: Sat Aug 21, 2004 6:58 pm; Truck: 1999 F-150 4X4 -5.4; Location: Denver, Colorado; My Truck Mods

Post by RkyMtnHi » Sat Feb 21, 2009 4:17 pm

It does to me.

The end of the 7 pin trailer tow harness where the trailer plugs in is round, so you need the corresponding 7 pin round plug attached to the trailer wiring.

hgoody77: New Member; Posts: 20; Joined: Fri Feb 20, 2009 4:46 pm; Location: Bartlett, Tn ( Memphis ); My Truck Mods

Post by hgoody77 » Sat Feb 21, 2009 4:52 pm

i think this is what i need under ther spare tire area.

RkyMtnHi: Hardcore Ford Truck Fanatic; Posts: 4596; Joined: Sat Aug 21, 2004 6:58 pm; Truck: 1999 F-150 4X4 -5.4; Location: Denver, Colorado; My Truck Mods

Post by RkyMtnHi » Sat Feb 21, 2009 5:16 pm

I am not sure what that is. Looks like a 4 pin trailer connector on the end. Doesn't look like the Ford connector in the schematics I sent you. Where did you get that picture?

hgoody77: New Member; Posts: 20; Joined: Fri Feb 20, 2009 4:46 pm; Location: Bartlett, Tn ( Memphis ); My Truck Mods

Post by hgoody77 » Sat Feb 21, 2009 9:25 pm

no not a ford connector. thats a Hopkins connector. it looks like it will plug right into the harness that is by the spare tire, more like a "T" and it has the 4 wire flat that will connect to the pig tail that i have for the 7 pin RV outlet i already bought. and then the red and blue wire just splice in. here are the two items. looks like it will work. in my head anyways. lol
Left picture: Hopkins 40145
right picture: Hopkins 47185

hgoody77: New Member; Posts: 20; Joined: Fri Feb 20, 2009 4:46 pm; Location: Bartlett, Tn ( Memphis ); My Truck Mods

Post by hgoody77 » Sat Feb 21, 2009 10:04 pm

on the picture on the right. the diagram shows that the center prong is "BU" back up? whats that like reverse lights?

RkyMtnHi: Hardcore Ford Truck Fanatic; Posts: 4596; Joined: Sat Aug 21, 2004 6:58 pm; Truck: 1999 F-150 4X4 -5.4; Location: Denver, Colorado; My Truck Mods

Post by RkyMtnHi » Sun Feb 22, 2009 6:58 am

Yes, look at page 2 of the schematic I sent. There is a drawing that shows what each of those prongs are for.

RkyMtnHi: Hardcore Ford Truck Fanatic; Posts: 4596; Joined: Sat Aug 21, 2004 6:58 pm; Truck: 1999 F-150 4X4 -5.4; Location: Denver, Colorado; My Truck Mods