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Old 11-07-2025, 01:43 PM   #1
bowt1ed
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Ignition switch sanity check

While wiring my new ignition switch with Painless kit, I'm checking continuity on switch poles, and I would think I should get a short across BAT and ACC when switch is in ACC position, but it's open. I'm getting it in the ON position, but not ACC. And the other positions (Start and Run) seem right to their respective poles. Am I missing something?
Cheer Jim
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Old 11-07-2025, 04:04 PM   #2
leegreen
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Re: Ignition switch sanity check

your switch has acc/off/on/run/start positions? What would 'on' be for?

Maybe on and run poles are both live at the same switch position to spread the load to two conductors? Which poles are hot in start position?

but to answer your question I would expect ACC to connect to bat when the switch is in ACC and RUN positions but not START
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Old 11-07-2025, 07:24 PM   #3
bowt1ed
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Re: Ignition switch sanity check

Sorry, by ON, I meant RUN. New (Classic Parts) original switch, has OFF (fully left), Position 2 (ACC?), Position 3 (ON/RUN), spring turn to START (releases to RUN).
Reading:
1) OFF Position- reading open from BAT to all posts
2) Position 2 (ACC?) - reading open to all posts
3) Position 3 (ON/RUN) - continuity from BAT to ACC and IGN 1
4) START Position - continuity to SOL (starter solenoid) & IGN 2

So, getting continuity from BAT to all as expected, except Position 2, which I assume is ACC...?
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Old 11-07-2025, 07:36 PM   #4
leegreen
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Re: Ignition switch sanity check

which positions does the key come out in?

you may have lock/off/run/start and no accessory-on position as modern cars have.
In off you can remove the key but the switch is not locked and you can still turn it with the ridges that come out around the key
In lock the key comes out and the switch can't be turned
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Old 11-07-2025, 07:39 PM   #5
bowt1ed
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Re: Ignition switch sanity check

Comes out in any position.
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Old 11-07-2025, 07:40 PM   #6
leegreen
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Re: Ignition switch sanity check

will the switch turn with key out in any position?
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Old 11-07-2025, 07:45 PM   #7
bowt1ed
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Re: Ignition switch sanity check

That's it. Must be the Lock, Off, Run, Start. Wonder why the ACC post then?
Thanks!
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Old 11-07-2025, 07:53 PM   #8
bowt1ed
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Re: Ignition switch sanity check

Yep, can switch between Off, Run, Start, but not back to Lock unless key is fully inserted. Cannot switch out of Lock without key fully inserted. That's it. I guess ACC just feeds switched 12V loads from RUN position. Thanks again!
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Old 11-07-2025, 07:55 PM   #9
leegreen
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Re: Ignition switch sanity check

They modernized from running the entire truck off the light switch to having a couple extra fuses tucked away and needed extra switch poles to hook things too.
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Old 11-07-2025, 08:03 PM   #10
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Re: Ignition switch sanity check

Makes sense. Cheers, Jim
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Old 11-08-2025, 04:38 PM   #11
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Re: Ignition switch sanity check

I don't think that a separate accessory spot was much of an issue as most of the TF trucks left the factory without radios. I think I stuck a cheap AM-FM hang it under the dash radio in my 57 panel.
I remember that all the time a friend of mine had his TF truck he never had a key for it that I know of. That was back when you didn't worry much about someone jumping in your work truck and taking off with it.
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