M38a1 ignition switch wiring

1952 - 1968, M38A1, M170, questions, discussions, regarding anything related to the M38a1 series.
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Mike Seymour
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M38a1 ignition switch wiring

Post by Mike Seymour » Sun Sep 23, 2007 3:46 pm

I'm doing a little modification and using a Packard connector ignition switch with my Douglas wire harness, using some pigtails that I got from Joe Hall in Maine. The Packard ends are lettered A through D but there are no markings on the switch sockets. I know where the Douglas ends go.
Can someone tell me the socket letters or numbers clockwise from the upper right around? or does it matter where I plug them in?

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Post by Cuz » Sun Sep 23, 2007 10:18 pm

Hello Mike,
I'm not familiar with that late model 4 terminal switch. Does it have any part numbers or manufacturer's markings on it? Is it a two position (on-off) switch? If it's a two position switch I would just ohm it out and select the paired terminals I needed. With the switch off and a number assigned to each of it's temrinals check between each with an ohm meter and list which if any have continuity with each other. The do the same with the switch on. Then post your finding here.
Cuz (AKA Wes K)
45 MB, 51 M38, 54 M37, 6? M101A1, 60 CJ5, 76 DJ5D & 47 T3-C

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DaveO
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Post by DaveO » Sun Sep 30, 2007 9:47 am

Hi Mike,

I'm in the process of doing the same thing. I was able to come up with this:

Looking at the back of your switch, starting upper-left, and going CW=

A B

C D

A and C are your hot feed to the switch, wire #11. It's the dual pigtail. It taps one of the lighting wires coming from the voltage regulator. The ignition switch hot connectors have those raised lines along the recepticle.

B is wire #27 which feeds the instrument cluster "spider".

D is wire #12, your distributor feed.

Mind you, I'm going solely by what is in my truck at the moment, and what tracing I've done in the less-than-desirable wiring diagram in the -8014. It sounds pretty reasonable to me, though.

Allow me to suggest using a dab of silicone grease on the rubber of the packards when you put them together. They are a bear to get apart when they've been assembled dry.

Good luck!
Last edited by DaveO on Sun Oct 14, 2007 11:26 am, edited 1 time in total.
Dave Ostlund
1941 WC9
1952 M37 W/W
1953 M38A1
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Post by Cuz » Sun Sep 30, 2007 11:09 pm

This is the dash section of the wiring diagram. The original switch had one power in (#11) and three power outs (27 instruments, 12 Ignition and 85 spare for accessory add-on)

Image
Wrong see photo below which is corrected to Dave's new data.

Dave, Can the switch power both B & C with only one #11 connected to either A or D?

So far what you describe would look like this:

Image

Image
Last edited by Cuz on Tue Oct 16, 2007 3:02 am, edited 1 time in total.
Cuz (AKA Wes K)
45 MB, 51 M38, 54 M37, 6? M101A1, 60 CJ5, 76 DJ5D & 47 T3-C

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NOTE! Correction...

Post by DaveO » Mon Oct 01, 2007 12:46 pm

Hi Wes,

NOTE! My previous posting was incorrect. I have since edited both of these entries. Wes' photo shows how I stated it should go earlier. Reverse C and D in the photo, and you are good to go. The way Mike wired it IS correct, though. Sorry 'bout that!

With my disclaimer in mind (this is what is on my truck, which doesn't look like anybody has been creative with the wiring), I would say that your picture is correct. According to my meter, the packard ignition switch is isolated A to B and C to D.

It would appear that 85 was eliminated if an ignition switch was changed to the packard style. Purely supposition, though.

Dave
Last edited by DaveO on Sun Oct 14, 2007 1:10 pm, edited 2 times in total.
Dave Ostlund
1941 WC9
1952 M37 W/W
1953 M38A1
M116

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Post by Cuz » Mon Oct 01, 2007 6:56 pm

That would make it a double pole single throw switch. So to get power from both B & C then both A & D need to have power in to them. This will require adding a second #11 wire and using a split one into two connector or splicing one end of two of the leads provided together. Which will work just fine.
Cuz (AKA Wes K)
45 MB, 51 M38, 54 M37, 6? M101A1, 60 CJ5, 76 DJ5D & 47 T3-C

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DaveO
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Post by DaveO » Tue Oct 02, 2007 3:27 pm

Indeed it would be a DPST. My rig has a molded dual pigtail on #11. I think I see one in the picture Mike provided. You can see what looks to be the beginnings of the molded block to the right of the switch. Difficult angle to tell, though...

Can you shed any light Mike?
Dave Ostlund
1941 WC9
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1953 M38A1
M116

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Mike Seymour
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Post by Mike Seymour » Tue Oct 02, 2007 5:09 pm

Just got back from another road trip and haven't been around..sorry..
So..with the help of you guys, I came up with this... Switch is in the same position as the first pic.

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Mike Seymour
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'53 M38a1 'Dagwood'
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DaveO
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Post by DaveO » Tue Oct 02, 2007 5:19 pm

That's ought to do 'er.

Out of curiosity, Mike, what are the tag numbers on the end of the dual douglas pigtail?

Thanks...
Dave Ostlund
1941 WC9
1952 M37 W/W
1953 M38A1
M116

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Mike Seymour
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Post by Mike Seymour » Tue Oct 02, 2007 6:26 pm

Dave,
From left to right..11, 12, 27 and 85. The instructions say 85 is an open connection..Must be for hooking up a heater or something else.
Mike Seymour
'43 MB 'Blondie'
'53 M38a1 'Dagwood'
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DaveO
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Post by DaveO » Tue Oct 02, 2007 6:54 pm

Mike,

Okay, so 85 is still in there. It indeed looks like the place I'll be plugging in the heater when I get that far.

Thanks!
Dave Ostlund
1941 WC9
1952 M37 W/W
1953 M38A1
M116

RTFB

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Mike Seymour
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Post by Mike Seymour » Tue Oct 02, 2007 7:52 pm

DaveO wrote:Mike,

Okay, so 85 is still in there. It indeed looks like the place I'll be plugging in the heater when I get that far.

Thanks!


Yup, I'll be doing the same, if I can find a water type M38a1 heater. This will be my wife's jeep and she doesn't want a gas heater...something about blowing up her and the grandkids :roll:
Mike Seymour
'43 MB 'Blondie'
'53 M38a1 'Dagwood'
SOMVCC
COG
MVPA #24294

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DaveO
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Post by DaveO » Tue Oct 02, 2007 9:46 pm

Can't say as I blame her. Those things give me the heebie-jeebies, too.

Bizal at Midwest Military has the NOS M38A1 water heater kits.

I modified a MUTT heater to fit my M37. The windshield defrost ability alone was worth the effort.

"Ory-gun", eh? I was stationed in Astoria. I would always cringe when folks would say "Ora-gone".
Dave Ostlund
1941 WC9
1952 M37 W/W
1953 M38A1
M116

RTFB

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Mike Seymour
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Post by Mike Seymour » Tue Oct 02, 2007 10:33 pm

You must have been in the Coast Guard. It's pretty but wet up in that neck of the woods.
My wife is a native and taught me how to pronounce "Orygun" many years ago.
I'll check on those heaters at Midwest..Thanks!
Mike Seymour
'43 MB 'Blondie'
'53 M38a1 'Dagwood'
SOMVCC
COG
MVPA #24294

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Post by Cuz » Wed Oct 03, 2007 12:43 am

Mike,
Where did you get that switch and the adapter lead set?
Cuz (AKA Wes K)
45 MB, 51 M38, 54 M37, 6? M101A1, 60 CJ5, 76 DJ5D & 47 T3-C

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