Battery Master Disconnect Switch Locations

thehueypilot

Active Member
Feb 25, 2004
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Medina,Tennessee
What are some good locations to mount a battery master disconnect switch for a trunk mounted battery? I have seen some mounted at the back plate holder, but where else would be a good location that is NHRA legal? Pictures would be great!
 
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Find one of the cars that hid the fuel filler cap under the license plate & take the
license plate holder from it. Then mount the switch behind the flip down license
plate holder.

Some electrical stuff that you may have already seen...

For a battery cut off switch, see
http://www.moroso.com/catalog/categorydisplay.asp?catcode=42225 is the switch
http://www.moroso.com/catalog/images/74102_inst.pdf
Use the super duty switch and the following tech note to wire it and you
will be good to go.

Use the Moroso plan for the alternator wiring and you risk a fire.
The 10 gauge wire they recommend is even less adequate that
the stock Mustang wiring.

There is a solution, but it will require about 40' of 18 gauge green wire.

Wire the battery to the two 1/4" posts as shown in the diagram.

The alternator requires a different approach. On the small alternator plug
there is a green wire. On the diagram it is #904, lt green/red wire that connects
to the alternator and dash light. It is the sense lead that turns the regulator on
when the ignition switch is in the run position. Cut the green wire and solder the
40' of green wire between the two pieces. Use some heat shrink to cover the
splices. See http://fordfuelinjection.com/?p=7 for some excellent
help on soldering & using heat shrink tubing.

Run the green wire back to the Moroso switch and cut off the excess wire.
Try to run the green wire inside the car and protect it from getting cut or
chaffed. Crimp a 18 gauge ring terminal (red is 18 gauge color code for the crimp
on terminals) on each wire. Bolt one ring terminal to each of the 3/16" studs.
Do not add the jumper between the 1/4" stud and the 3/16" stud as shown it the
Moroso diagram.

How it works:
The green/red wire is the ignition on sense feed to the regulator. It supplies
power to the regulator when the ignition switch is in the run position. Turn
the Moroso switch to off, and the sense voltage goes away, the voltage
regulator shuts off and the alternator quits making power.

See the following website for some help from Tmoss (diagram designer) &
Stang&2Birds (website host) for help on 88-90 wiring and lots more…

http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif

Diagram courtesy of Tmoss and Stang&2birds.
fuel-alt-links-ign-ac.gif
 
bullitstang1313 said:
I mounted mine underneath the license plate so nobody could mess with it when I'm just out around town and when I go to the track, I just pop the license plate off and there it is.

Im with him. I just made some brackets to move the plate out enough to clear the switch. You have to move the plate out about 1" and you cant even tell you changed anything.
 
mustangnick said:
YOU CAN MOUNT IT ANYWHERE YOU WANT AS LONG AS IT IS IN THE REAR. I MOUNTED MINE NEXT TO THE LICENSE PLATE. I JUST PUT NEW HOLE IN THE PLATE AND MOVED IT OVER.
this is the exact thing i did. I wanted to do a nice switch through a tail light but it wasn't going to be very easy so a moved the licence plat over.