Using unused circuits in power dist. box

Manta22 · Jul 26, 2015

I am looking to add a couple radios to an '09 Expedition. I see there are several locations in the power dist. box under the hood at the front that are labeled as "Unused". I checked and they all have power on the one tab that is present. How do I add a power out tab to take advantage of this fused power supply?

I install the radios in a console and usually put a simple fuse block in there with a 6 or 4 gauge power lead and identical size ground lead. I do put a maxi-fuse holder inline under the hood before the firewall as a precaution, but there is almost nowhere to put one in the Expedition and still keep it accessible.

stamp11127 · Jul 26, 2015

It depends on the connectors used in the distribution box. Once you source those it is straight forward addition. The easiest way would be get a second box from the junk yard and rob the connectors from it. The other would be to source them from companies like Mouser.

How many amps will the circuit draw?

I doubt the box is designed to pass over 40a on a single circuit if it is using a PC board

Manta22 · Jul 26, 2015

Each radio (3 total) would draw up to 15 amps (radios come with 20a fuses, but manf. say radio won't draw more the 15). My idea is to build a harness and connect each radio to a separate unused circuit - there are 8 total.

stamp11127 · Jul 26, 2015

I would open the distro box to see how they made the existing 20a connections. If it is on a board you may have to beef up the existing traces to handle the load.
Another thing to consider is at idle the alt won't cover the 45a load the radios are adding to the existing load.

Manta22 · Jul 26, 2015

The radios only draw that much when transmitting. They usually draw 2-3a monitoring and 5a when receiving. I don't see all three transmitting at one time.

stamp11127 · Jul 26, 2015

Even though you don't plan on transmitting on all 3 at the same time, you should wire so that you could.
You will need through hole female spade terminals in order to add the additional circuits. Check with your local Ford Dealer Parts Dept. to see if they have a source for them. If not I would try an get a distro box from the junkyard to use as a donor - same year if possible.

Manta22 · Jul 27, 2015

It looks like the circuits are powered off two buses, not a circuit board. The front/bottom row has two 60a fuses.

I have my local Ford parts guy scratching his head and looking around now.

stamp11127 · Jul 27, 2015

If you can take high resolution pics of both sides of the internals of the distro box and send them to me I would appreciate it. That would help others in the future if they needed to know what was in there prior to adding circuits. Also if you could get a closeup of one of the terminals and how it mounts that would aid in finding them.

Manta22 · Jul 29, 2015

According to my local Ford dealer, no can do. Ford does not make those connectors and if there is a pin problem, they have to replace the whole box.

Time to hunt around some more...

stamp11127 · Jul 29, 2015

They say that since it isn't a normal type of "repair" and individual components that are on the boards will not be listed in their parts database.

Some of the manufacturers will stamp their logo or name on the part if it has enough room. One of the common manufacturers is AMP. Expect to spend hours looking for a source, I've spent a good day looking for specialized connectors on and off back when I was in the parts position.

Without knowing what type of female connector was used on your model year it will be a crap shoot to find the correct version. I did run across a fuse box repair on a Ferrari that shows how Ford may have constructed your distro box. To add the circuits to yours would be similar.

Fuse box repair on Ferrari:
http://www.ferrariaustralia.com/Technical/fuse_panel_repairs.htm

This link will give you an idea of just some of the terminals that are available to manufactures:
http://compass.alibaba.com/tag-sear...5770832170.html?spm=a2700.7724838.19.4.tY7Nzx

Using unused circuits in power dist. box

Manta22

Member

stamp11127

Full Access Members

Manta22

Member

stamp11127

Full Access Members

Manta22

Member

Attachments

stamp11127

Full Access Members

Manta22

Member

stamp11127

Full Access Members

Manta22

Member

stamp11127

Full Access Members

Similar threads

Latest posts

Staff online

Members online

Forum statistics

Share this page