On my 1999 I have the 4 pin trialer harness. I want to put in a 7 pin with electric brake. Any advice?

 

The 1999 can be a bit strange, depending on the build date.

The fuse panel might be the type of a 2000 MY, which all the fuse and relays for the trailer tow adapter are going to be in the fuse boxes themselves.

The trailer tow adapter, you should be able to switch out from a 4 pin, to a 7 pin. The connector should be up along the frame rail.

There is a sticky in the Towing and hauling forum for the part numbers, this is from a 2001 Trailer Tow adapter install directions.



https://www.f150online.com/forums/to...locations.html

There are a few locations online to purchase the trailer tow adapter ( both online Ford parts places, as well as aftermarket ), and the pigtail for under the dash for the trailer brake hookup.

The relay part numbers should be listed for the 97-03 MYs.

If you want a PDF of the 2001 MY trailer tow install directions, drop me an email via my profile, and I can send it to you. This might help with your install.

The relays can be found at Autozone or the likes. Just have the Ford part number for a cross reference.

Take a look under the hood, to see if your fuse panel looks like this ( picture from 1997 & 1998 MY, some post have 1999 MYs with this as well ).

 

I tried loading pics put I can't. On my posting rules reads "can not post attachments". Can I get that changed?
My fuse panel does not look like the pic. I see the see the harness on the frame rail, this looks easy to change out. I am just going to need details on the fuses and relays.

 

If you go under your profile, you can create an album, and add pictures to it. The attaching pictures has been shut off some time ago due to a security hole ( been that way since I have been here ).

https://www.f150online.com/forums/me...9fordf150.html

If you Fuse box does not have either aux box ( the relays or the 5 slot fuse panel ) then it is the same as the 00-03 MYs.

The details on the fuses and relays are in the sticky linked above ( URL just below the picture of the trailer tow harness ).

 

If I buy a 7 pin wiring harness that plugs into the 4 pin connector and I put the relays in the fuse box. Where are the wires located that come off the fuse box?

 

The harness shown above, and referenced in the Towing and Hauling forum actually replaces the current 4 pin one you have with the 7pin & 4 pin combo.

The picture above shows what is being installed. The 4 pin version you have, you will remove first.