For the wiring wizards

[djmac]

I am installing a 2 speed taurus fan under my hood. I also have several after market wires running to my solenoid post (fuel injection msd electric fan etc) which I would like to consolidate in a neat way. So I took a shot and bought a 97 Mercury Sable power center for 25 dollars off ebay. I thought I could run a heavy guage cable from the solenoid to the line side of the power center then run all the miscellaneous stuff to the power center which has lots of fuse ports. Now that I have it I have a few questions. There is a connection for a large Battery feed (8 guage ?) and a large alternator feed (6 guage?) What is the alternator feed about. Currently I have 2 #10 wires from my alternator that run to my solenoid (ford engine and alternator) should those go to this side of the power center? Also I was hoping to find a fan relay in this power center. I see a fuse location marked fan and number of relays that are for other accessories. At any rate it looks like I can remove the existing relays to make room for the fan relay but the question is: Is there a 80 to 100 amp relay that will fit in the standard relay socket found in the power center? Hope I did not make this issue to confusing, thanks for any help in advance.

[djmac]

bumpity bump

[Junk Yard Genius]

Since you didn't post pictures of what you purchased, I'll have to take a broad stroke guess...

One battery terminal on the end, and right next to it a terminal marked for the alternator feed.
The battery feed is a direct feed of about 6 Ga. wire with no fuse or fusible link.

There should be a fusible link or master fuse between the battery & alternator terminals, and probably a cover over the master fuse/fusible link and master terminals if the 'Power Center' you purchased is all there.

The fuse is in there to keep the alternator from ruining the battery and the rest of the wiring if the alternator goes 'Full Field', that means putting out about 40 volts and around 75 to 100 amps.

You should have a set of relay positions, most of which are single usage relays.
There may be some dual use relays in there somewhere, but I haven't worked on a Taurus in more than five years...

The fans on some models use two relays in parallel. I remember that because it seemed odd to me at the time.

You should have a number of fused outputs.

And one diode polarity protected output.
I don't remember what the diode was for, I just remember the diode being there.

Your best bet is to spend a few bucks for a DVM (Digital Volt/Ohm Meter),
Radio Shack has one for under $25, Wally-World has them (Chinese crap), but I'm not up on the price.
Sears sell them for about $25 and Harbor Freight has them for about $5 (Chinese crap).

Map the outputs or take really good pictures and post it here and I'll have a look.

[djmac]

Right on the money site unseen!! The batt and alt are protected by the fuse. there are 2 5 terminal plug in relays. The cover seems to indicate they are 2 the windshield wipers and blower motor but when you check the path of the conductors the 40 amp fuse marked cooling fan is fed from one pole of the relays which would seem that this was a fan relay. Whan I am hoping to do is to use these 2 relay space and feed my soon to be installed 2 speed taurus fan. I am thinking if I use a 40 amp fuse and relay to feed each speed I should be able to feed the fan pretty well. As I mentioned along with feeding the fan I was hoping to clean up some of the underhood wiring by using the same power center and just relabel the cover to indicate what the fuses locations are really feeding. Do you see any problems with my plan? Also, what is the difference between single use and dual use relays? And another question; Currently the Batt wires from my alternator go the battery side of my solenoid. If I move them to the alternator terminal on the power center and then hooked up a heavy guage wire from the battery to the batt side of the power center wouldn't that be doing the same thing only with the improvement of the fused protection between the two terminals?

[Junk Yard Genius]

The five terminal relays are dual use.
Dual use just means they have the potential to power two things when activated, nothing more.

Four terminals are single use and power only one item per relay.

Battery power should be direct feed with no fuse of any kind. (that's what the item fuses are for.)

The alternator should have a fuse between it's terminal and the battery terminal.
Keep it there or use a fusible link in there.
Alternator fuse keeps the an alternator melt down from killing the vehicle wiring.

You can use the fuse slots for anything you want, but keep a mind towards your wire size.
Small wire and a big fuse can have the effect of the wire melting/burning before the fuse.
So, with a big fuse, use a bigger wire,
For a small fuse, you can get away with a smaller wire.

Pay attention to the wire size connected to the terminals, this can be the 'burn point' of you connect a larger wire to it and stick in a fat fuse.
It's better to hook your new wire up to the fuse socket if you can get to it.

The rule of thumb when you are a novice is to use larger wire...
14 gauge wire use a 10 amp or smaller fuse.
16 gauge wire, use a 5 amp or smaller fuse.

The only thing that should draw more than 10 amps is your ignition (10 amps is plenty for the Ford DuarSpark system),
Your head lights, your parking/tail lights (These are separate circuits running through the same dash switch)
... I can't think right now, but I'm sure there is something else...

When in doubt, use a smaller fuse and work your way up to the wire gauge limits...

[djmac]

Great info. Sounds like hooking up my alternator batt terminal wires to the power center is the right way to go. Right now it goes straight to the solenoid post where it meets the battery cable without any current protection. The power center has built in overcurrent protection. Sounds like if I wire the 2 relays in parallell to the taurus fan I can make use of the relay locations as well. Thanks for your time.

[Junk Yard Genius]

Normal alternator feeds come to the battery cable side of the starter solenoid for a reason...

They do have over current protection, it's called a fuseable link, and it's usually the first 4" or so of the wire going to the alternator 'Batt' terminal.

The reason the fusible link is at the starter solenoid is because if the alternator shorts out internally, or the heavy wire is pinched or mashed, the fusible link will fry.
If it's attached to the battery, the hot wire/fire may ignite the battery gasses, so the fusible link is mounted at the starter solenoid where it's unlikely to spark a battery explosion, but it still has unrestriced current flow to the battery.

A fusible link usually feels different than regular wire, and a fusible link usually has a plastic collar attached about 3 or 4" down from the 'eye' terminal where it connects to the actual wire.

Fusible links should be two wire sizes under the feed wire you are using.
IE: 10 Ga wire, use a 12 Ga. fusible link.
12 Ga wire, use a 14 Ga. fusible link.

[djmac]

Normal alternator feeds come to the battery cable side of the starter solenoid for a reason...

They do have over current protection, it's called a fuseable link, and it's usually the first 4" or so of the wire going to the alternator 'Batt' terminal.

The reason the fusible link is at the starter solenoid is because if the alternator shorts out internally, or the heavy wire is pinched or mashed, the fusible link will fry.
If it's attached to the battery, the hot wire/fire may ignite the battery gasses, so the fusible link is mounted at the starter solenoid where it's unlikely to spark a battery explosion, but it still has unrestriced current flow to the battery.

A fusible link usually feels different than regular wire, and a fusible link usually has a plastic collar attached about 3 or 4" down from the 'eye' terminal where it connects to the actual wire.

Fusible links should be two wire sizes under the feed wire you are using.
IE: 10 Ga wire, use a 12 Ga. fusible link.
12 Ga wire, use a 14 Ga. fusible link.

Sorry for picking your brains so much but I am getting a good education here. So the fuse between the alt and batt lugs on the power center would not be as good protection a fusible link. Assuming that is true what normally attaches to the ALT lug on the power center. Maybe in my adaptation I should not attach anything to the ALT lug and just run a heavy gauge wire to the Batt lug? Thanks for your patience.