The Stovebolt Site Forums The Shop Area The Electrical Bay Ignition Switch Post Identification

I started a rewire of my 51 Chev 1/2 Ton Surburban about a year ago. Old age has apparently caught up with me or just have a severe case of "CRS". I forgot which post is which. Ignition switch has three posts. One post is centered at the bottom. I presume this is the hot (to battery) post. Which one of the other two that are situated above and off center of the hot post is the #2 post. The switch is orginal. Converted the system to 12 volt about 5 years ago. Thanks in advance......

OldArmy,

Last weekend I re-wired under the dash of my '54 Suburban and the ignition should be same as in your truck. My diagrams show the battery (B) post at the bottom, as you indicated.

If you are looking at the switch from the back (laying on the floor and firewall), the post on the right is Ignition (I). The third post (A) is to the left, above the B (Battery) post.

B at 6 o'clock
I at 2 o'clock
A at 10 o-clock

Does anyone know if the "A" post stands for "Accessory"? I have not tested when "A" is hot. Is it hot all the time or only when the key is "On"? What would be connected to "A"?

None of my wiring diagrams or accessory installation diagrams show anything connected to the "A" terminal.

Tim

Whilst on the subject of ignitions someone in the alternator category mentioned something about a new switch. Would that be anyone of the ignition switches advertised in the many chev catalogs? I also converted to an alternator but since my recent rewire am just trying to make sure I have all my wires connected correctly. It can't be that difficult but I have melted a couple of wires in my attempts of getting it right. Marc

I posted something like that in the past. I was using my orig ign switch (52)Chevy with my 12 volt alternator system. The switch contacts (on/off)only were a hit and miss at best sometimes so I switched out to a new (universal 3 position switch) that fits nice in the hole and almost looks like it belongs there. Can get at any or most auto parts places and is about $9.00 to $12.00.
T

:)howziit OldArmy!

i've had some background in army aviation electronics, and my Verizon career, so i always treasure my trusty volt-ohm meter(VOM), as a must-have tool.

it has also served me well, in trouble-shooting auto electrical problems, and can be purchased very cheaply.

be very sure that the battery is disconnected!

NOW...using this simple tool handy, turn the ignition switch to the "7 o'clock position". using the two meter's leads, touch any two screw terminals, until you get a reading of ZERO on the meter.

make a note of which terminals; these are your IGNITION ON positions.

NOW...turn the switch to the "4 o'clock position". touch any two screw terminals,so you get the ZERO reading.

note these terminals; these are your ACCESSORIES position.

if you have a fourth spring-loaded "9 o'clock position", touch any two terminals, for a ZERO reading.

note these terminals; these are your STARTER ON position.

looking at your notes, you will find ONE terminal that is common to all the tests.

THIS IS YOUR BATT+(hot lead); all the other leads are where you hook up ignition,accessory, and starter.

JMO, buy an ohm-meter, and practice with it. it will save you lots of unnecessarily-cut wiring, major headaches, untimely stalls, and $$$$ given to the repair shops.

makes you feel good to know which goes where,and why... even if all the wires were same color.

hope this helps.