Technical Tri 5 to 60's GM ignition switch question

Hi, I've got a 1957 Chevy and a '57 (CDN) Pontiac they came without an ignition switch. I guess over the decades the key was lost and someone had to pull the switch to jimmy up a starter button. The Canadian Pontiac is basically just a rebodied '57 Chev...easy right? Not really because in '57 they used 2 different ignition switches and wiring circuits. Wiring circuit A is (I believe) the "new" harness with B being ( I think) a hold over from '55-6.....neither one of these switches is readily available leaving the interweb specialty vintage suppliers like Danchuk etc. but it's a real rabbit hole with ordering the wrong parts more than just a possibility...or Ebay and hope you stumble across a good OEM switch I have next to no faith in either (actually Danchuk only has 2 pics of the side of their switch not the blades so it's useless) ....luckily although everything else was tossed I found the base plate w the blades... it'a 5 blade (pin)unit
Most of the usual players are present: ACC, BAT, SOL, self explanatory the other 2 are marked IGN 1 and IGN 2
IGN 1 & ACC are 12V "hot" on RUN...IGN 2 and SOL are 12V hot on START
So I talked to my local NAPA and found they can only go back as far as 1960 Bel Air that switch is also 5 pin but marked as follows: ACC, BAT, SOL, IGN and GRD so here's the million dollar question is GRD "hot" on START? can I basically use it as the old switch used IGN 2? I mean the switch is grounded to the dashboard (although it's not necessary) so what is GRD? not a ground obviously...I propose to pull the spades from the socket and run the wires to the BR and back from the BR siamesed to the GRD connector instead of IGN 2...so 12V on START and 8V on RUN
**These pics are of the '57 (not the one I'm dealing with) switch and harness, some of which show 6-7 pins but no idea how they're marked... the diagram doesn't show a GRD an seems to be missing the ACC pin altogether...yes it does show the GM part# but no one can cross reference it anymore

 

Okay, so this is WHAT YOU HAVE.

Commonly and typically, there may be some exceptions, ignition coils got direct power on 6 volt cars. When 12 volt started taking over, most all had a resistor inline for running so the ignition circuit didn't have high amperage which would burn up the points. Many had a bypass for full 12 volts during cranking to make up for the voltage drop during the high draw.
So without knowing this exact case (57 Pontiac Canadian), my guess is that IGN1 is the running ignition circuit and that IGN2 is the bypass ignition circuit. This should be shown in the wiring diagram.

As for the other stuff with a different car/year GRD, I think you are just confusing things for yourself.
If you need to confirm using the newer switch for the old application, you should first confirm how your missing car switch operates (this is hopefully done using the WD), then test the new switch using an ohmmeter at the store before you buy.

 

Thanks i'm not sure how the meter would help unless I could also hook it up to 12V I'm not sure how the parts guys would react to me walking in with a battery, a meter, and wires ...I've boiled it down to whether or not GRD is 12v hot on START if it is then great should function exactly as IGN 2 if it is a ground of some kind then back to searching...doesn't make sense that it's a ground though because it's on the baseplate not the metal part of the switch

 

There is no need to 'power' the switch with a battery and wiring to check it's operation. It is a mechanical switch that closes metal contacts together depending on position.

Testing the switch using just an ohmmeter should not worry a counterperson.

Ground is either the exact function of your switch, which is continuity between B+ and IGN2 (old terminals), B+ and GRD terminals (new switch) in the START position, which is most likely.
or
it has continuity between the IGN2 (old switch)/GRD (new switch) terminal and the base of the switch attached to the metal dashboard when the switch is in the START position or some other ground source. This is unlikely, since as you mention it has a dedicated terminal that is not attached to the switch housing.
However, Chevy did do some grounding through the switch back then.
https://www.stevesnovasite.com/threads/continuity-on-ignition-switch-in-all-key-positions.654289/

 

can't say I'm too familiar with Ohm meters just the old school touch the wires together "Oh my! meter"

 

Same thing, 20 or 200 ohms scale
infinite or out of range (OR) = no continuity = not connected = no beep (hold two ends apart)
number close to zero ohms = continuity = connected = beep! (hold two ends together)

Ohms are used on stuff that does work or draws power (coil windings, resistors, motors) to check that they are in spec.
It is also used to check circuits (wiring) to make sure they are complete (no open circuit = broken) and no high resistance (corroded connectors). This is what is being done with the switch, to make sure the terminals that are switched together complete the circuit.

 

As @RodStRace mentions above, you will be testing for continuity between terminals, when switch is turned to the varying positions, not voltage/power.
I have an inexpensive one, it doesn't go "beep". Just watch the meter.

 

You said, “luckily although everything else was tossed I found the base plate w the blades... it'a 5 blade (pin)unit
Most of the usual players are present: ACC, BAT, SOL, self explanatory the other 2 are marked IGN 1 and IGN 2”

https://www.ebay.com/itm/2661408916...w59L/OmcoGz6dAK80+qwZJwTY=|tkp:Bk9SR5iWsYzrYg

 

Thanks @Johnny Gee which according to some info is a 55-6 style harness...the Ebay switch shows the correct positioning of the terminals:
*note the space marked GRD but absence of terminal*... but it's obviously old and crusty...and I have NAPA down to $38. on the '60 switch and $21. on the lock cyl. vs. $50. US + shipping(if they even ship to Can.)...I was really hoping one of the dudes here would recall that GRD is hot on START from dealing w this in the past or have a '60-'65 GM switch layin around to test...

 

Ground is just that. That ground terminal will make contact with the housing of the switch. Its only purpose is for idiot lights that typically never come on due to such things like never over heating. So that terminal will cause the lamb to light up upon start position as a form of bulb check.

As for ignition 1 & 2 how will you resolve this with the NAPA switch?

 

Awesome @Johnny Gee I think we're on the right track since it is isolated from the main body I'm going to say that it's "hot" (12V) on start and "cold" on RUN which should be technically the same as IGN 2 ...once the ballast resistor "in" and "out" are connected to this GRD terminal it should shoot 12V to ignition on START and carry the 8V on RUN...like it did w the dummy lights that only come on at START position...

 

IGN 1 to ballast resistor then to coil.
IGN 2 direct to coil (or out put at ballast resistor) for full voltage upon start up.

 

You know I did something similar to this years ago on a '57 and I just left the switch hanging under the dash not bolted in the dash and it functioned just fine is this not possible in a '60-'65?...I understand a switch can work both ways where a light + is hot and ground is switched but that would mean the case needs to be grounded to the dash as well...so why have it isolated in the back plate ...wouldnt the rotor contacts inside the switch be sending power from batt to ign. 2 but grounding at GRD at the same time then? doesn't make sense

 

I’m lost about why ground terminal is an issue here?

Your Pontiac has a Temp Gauge and not a Temp Light?

You have a Chevy 283 with Pontiac script on the valve covers? What trans behind it? I ask because I want to know which type starter you have as for as wiring connections to it.

 

bone stock 235 and 3 spd. luckily doesn't appear as though any of the wiring is cut or f'ed with so all wiring/connections are o/g...it's this later model switch that I need info on... either GRD goes "hot" while in start or it doesn't... in which case back to looking for later model solutions on the switch...spending 3x the $ & waiting 3 weeks for a crusty old part does'nt appeal to me as much as pulling the spades out of the plug to reconfigure the wires

 

because GRD spade is on the later '60 switch I want to use... if GRD "hot" at START then it functions the same as IGN 2 on the '57 switch ...otherwise the switch is "hot" at IGN but "cold" at GRD in START position which seems odd

 

Just a cut and paste to read and chew on, gather what you can for info, and the light will come on.

GM

Ground - 18 ga. Dark Green wire to temp sending unit (goes to ground when hot) and to temp gauge or light
IGN SW Accy - 18 ga. Black wire and Brown/White wire from Fuse block and ALT sense wire
SOL - 12 ga. Purple wire to Neutral Safety Switch then to starter
BATT - 12 ga. to Cigar Lighter, Head light switch, fuse block, Horn relay and Battery 12v+
IGN SW IGN - 18 ga. Blk/Pink (switched) fuse block, Coil and going to all the POS side of the Dash indicator lights ie, OIL, TEMP light or Gauge, GEN or ALT light, Pos 12V+ for Gas Gauge.

Painless

GROUND - not used
IGN SW ACCY - Brown wire 12.ga. #932 Origin from fuse block
SOL - Purple wire 12.ga. #919 Origin from starter
BATT - Red wire 12 ga. #934 Origin from fuse block
IGN SW IGN - Pink wire 14 ga. #931 Origin from fuse block (MSD 6AL ignition.)

Hope this helps

 

No, ground does not function like that. I still need confirmation that your Pontiac has a Temp Gauge or Temp Light before I go any further. I’ll address things now that I know you have a 235 3 on the tree as well.

 

By the way, I fully understand wanted to use another switch. Did you have it yet? If so post a pic of the back side and it’s markings.

 

@Johnny Gee looks like you're right it seems to be right at the edge of the case...i geuss this is the plan B https://www.amazon.ca/Waterproof-31...59-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9idGY&psc=1

 

not yet ...I won't pop for it if it's not hot in start... have to keep looking I guess

 

You’ll be better off with a unit like this that a local NAPA would have on hand.

 

^^^^^ So long as the nose is long enough so it’ll fit the dash ok.

 

As for IGN 1 and 2 there’s a way around that. But that’s for later.

 

I have this switch, it's from a Pontiac, not sure of the year, nothing older then '65 I would guess.

This one is also a Pontiac, '65 big car most likely
I can test them if you need to know something about them or you need one

 

@Joe H this one is interesting because it's exactly the same as my missing one except it has the ground post ....any part # on it? or maybe recall what it came from?

 

I went ahead and ordered that style...but Joe H made me think maybe there's a mid 60's Pontiac starter switch out there that is nearly identical...so I dont have to cut anything (preferably) ...I'm going down the rabbit hole again lol

 

Sounds like a plan with Joe’s offer. The GRD terminal is a later feature. Just disregard it.

 

You never did answer about temp if it’s a gauge or a light?

 

I dug these out of dad's stash of parts, he parted out a '67 GTO, and his '65 Catalina, and I replaced a '65 Lemans switch with a later one, so it might be any one of three cars.