Install of master shut off switch
- Thread starter old31
- Start date
Big hammer
Well-known member
I would switch the ground , battery ground to switch then back to a ground . I use Fords disconnect , remove the battery ground cable terminal from the battery ! flip up the rubber mat , pop the oblong cover , twist and pull the terminal , easy peasy ! Don’t install the terminal so tight that you can’t remove it by hand, in a emergency it can be done very quickly !!
Jim Brierley
Well-known member
me too. I have locate the switch inside the car where it is easily reached.
Dan McEachern
Senior Member
Front of seat riser is one place you might consider mounting it. Run the cables up thru the floor of the seat pan with grommets.
Y-Blockhead
Well-known member
I agree, my shut-off switch is on the ground wire. Mounted thru the floor in front of my seat in my Town Sedan.
Y-Blockhead
Well-known member
I run mine Battery + (if your car is + ground) > switch > ground. Starter is out of the picture.
jeepguy1948
Well-known member
I also install the disconnect switch in the ground wire (+ side for positive ground, - side for negative ground). Nobody has ever explained the rationale for this method but in my mind I believe that it is because if one of the cables shorts to ground it is not a dead short (I hope my explanation makes sense). There may be other reasons but I am unaware of them.
I have a good idea making this way too complicated than it needs to be, but I am confused on this.
My car is positive ground 6 V.
So you take one cable from the plus battery to the off side on the master. Then where are you running the other cable from the on side of the master to?.
My car is positive ground 6 V.
So you take one cable from the plus battery to the off side on the master. Then where are you running the other cable from the on side of the master to?.
jeepguy1948
Well-known member
It seems that the most common location to attach the wire is to one of the transmission bolts (this is probably where the ground wire is attached now).
There is a hole in the front of the middle cross member, immediately adjacent to the back terminal of the battery, that is the master ground for the chassis. Often people run a supplemental ground from the transmission or flywheel housing to the frame as well, this can improve starter performance. But you need to ground the battery (or in old31's case, the wire from the cutoff switch) directly to the frame at a minimum. All the other grounds from the car - headlights, taillights, horn, instruments, etc. are grounded to the frame. If you do not connect the ground from the battery directly to the frame then you run the risk of accessories not working, not to mention that you set up a potential voltage drop from the frame to the engine - which might result in a shocking discovery of the problem.
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47topless
Well-known member
To starter
ModelA29
Well-known member
The simple answer is - use either cable. That cable gets the switch installed to it. You can cut the cable and add a couple terminals to it or just add another length of cable to go from one side of the switch to what you disconnected the cable from (starter or ground). Mount it where it's easy to use - or you won't use it. Our Tudor is under the hood so unless it's going to be parked for months it's always on.
Keith True
Well-known member
47,you are sending him in the wrong direction.He has a positive ground system,with one cable hooked between the + on the battery and the switch.The other side of the switch needs to connect to the car ground,frame,trans,etc,NOT to the starter.
Dan McEachern
Senior Member
Batterycablesusa.com is a great source for cable, terminals and shrink wrap.
47topless
Well-known member
Thank you for correcting my error. I apologize.
