M38 24V SW Temp Gauge screw-up

arisLgr · Posted: Sun Aug 27, 2017 8:59 am Post subject: M38 24V SW Temp Gauge screw-up

Hi guys, I really screwed up my NOS SW temp gauge! It was working but showing lower than actual temperature, so daft me, to check it I hooked it up straight on to 24 volts and BANG, it died on me!
I'm sure I must have burned it so with replacement prices sky-high, does anyone know of a repair shop for those gauges?
Embarassed

_________________
Aris
Willys M38
1936 Cord Phaeton
1954 Mercury Monterey
1968 Corvette Stingray
1973 Mercedes 350SE
1974 Montesa Cota 247T
1982 Kubota B7100

4x4M38 · Posted: Sun Aug 27, 2017 9:24 am Post subject:

Aris,
What are the part numbers on the gauge?

How exactly did you wire it to 24 volts?
_________________
Brian
1950 M38
MC11481
http://www.willysmjeeps.com/v2/modules.php?set_albumName=album372&op=modload&name=gallery&file=index&include=view_album.php

w30bob · Posted: Sun Aug 27, 2017 9:29 am Post subject:

Hi Aris,

The plastic lens for these gauges is held on by a "crimped-on" ring and is not intended to be removed. If you can find a way to re-crush the ring you could possible pry the ring up with a screwdriver from the backside and take gauge apart.........but they weren't designed to be taken apart.

Even if you got it apart......if you fried the small wire coil....it's toast. You're only real option is to replace it with another gauge. You see these gauges used at the meets for pretty cheap all the time.

regards,
bob

wesk · Posted: Sun Aug 27, 2017 3:37 pm Post subject:

Only the extremely early M38 gauges were 6 volt and used the external 95 Ohm resistor. The rest are 24 volt (having internal resistors) so they are connected directly to 24 volt all the time.

Let us know the actual part number of the gauge you fried.

AC # 1512244, WO# 118105, ORD # 7728855 is the very early M38 MC10001 thru MC17855 units used with the external resistor.

All of these temp gages are with Internal resistors and connect directly to 24 Volt:
AC # 1512422, SW # 505A, WO # 119086, ORD # 7389567 AC # 1512669, SW # 505N, WO # 811244, AC# 1512676, AL # EO-11933, SW # 505K, WO # 808568, WO # 809822, ORD # 7954511.

AC = AC Delco
AL = Autolite
SW = Stewart Warner
ORD = US Army numbering
WO = Willys-Overland numbering.
_________________
Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100

Mjeeps photo album: http://www.willysmjeeps.com/v2/modules.php?set_albumName=Wes-Knettle&op=modload&name=gallery&file=index&include=view_album.php

arisLgr · Posted: Mon Aug 28, 2017 5:02 am Post subject:

Thank you all for the replies, the gauge is still on the Jeep and I will be able to remove it in a couple of weeks, at that time I will post it's SN!
_________________
Aris
Willys M38
1936 Cord Phaeton
1954 Mercury Monterey
1968 Corvette Stingray
1973 Mercedes 350SE
1974 Montesa Cota 247T
1982 Kubota B7100

4x4M38 · Posted: Mon Aug 28, 2017 8:06 am Post subject:

Aris,
The numbers we are asking about are on the face of
the gauge, usually at the bottom, sometimes just below
center, and sometimes at the top.

No need to remove the gauge to find these numbers.
_________________
Brian
1950 M38
MC11481
http://www.willysmjeeps.com/v2/modules.php?set_albumName=album372&op=modload&name=gallery&file=index&include=view_album.php

wesk · Posted: Mon Aug 28, 2017 8:49 am Post subject:

No need to remove the gauges. The part numbers are on the front (face) of the gauge.

_________________
Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100

Mjeeps photo album: http://www.willysmjeeps.com/v2/modules.php?set_albumName=Wes-Knettle&op=modload&name=gallery&file=index&include=view_album.php

arisLgr · Posted: Fri Sep 08, 2017 11:21 am Post subject:

OK here it is

_________________
Aris
Willys M38
1936 Cord Phaeton
1954 Mercury Monterey
1968 Corvette Stingray
1973 Mercedes 350SE
1974 Montesa Cota 247T
1982 Kubota B7100

4x4M38 · Posted: Fri Sep 08, 2017 4:10 pm Post subject:

That's a 24 volt gauge. It would seem
the only way you could have damaged it
was to reverse the leads.

You might still go through the gauge troubleshooting
procedures just to confirm it's toast.

If you are still in need of a gauge the brethren here
may be able to help.

Take care,
_________________
Brian
1950 M38
MC11481
http://www.willysmjeeps.com/v2/modules.php?set_albumName=album372&op=modload&name=gallery&file=index&include=view_album.php

baios · Posted: Sat Sep 09, 2017 7:27 am Post subject:

aris baios here any foto of yr m38? Wink

arisLgr · Posted: Sat Sep 09, 2017 10:25 am Post subject:

Any links for the gauge troubleshooting?
_________________
Aris
Willys M38
1936 Cord Phaeton
1954 Mercury Monterey
1968 Corvette Stingray
1973 Mercedes 350SE
1974 Montesa Cota 247T
1982 Kubota B7100

4x4M38 · Posted: Sat Sep 09, 2017 10:29 am Post subject:

Top left, under downloads.

M38 electrical heading.

http://willysmjeeps.com/downloads/instruments.pdf
_________________
Brian
1950 M38
MC11481
http://www.willysmjeeps.com/v2/modules.php?set_albumName=album372&op=modload&name=gallery&file=index&include=view_album.php

arisLgr · Posted: Sat Sep 09, 2017 10:34 am Post subject:

Thanks a million Brian !
_________________
Aris
Willys M38
1936 Cord Phaeton
1954 Mercury Monterey
1968 Corvette Stingray
1973 Mercedes 350SE
1974 Montesa Cota 247T
1982 Kubota B7100

arisLgr · Posted: Sat Sep 09, 2017 11:01 am Post subject:

Well, I bench tested the gauge with a D 1,5 volt battery then with a 3,7 volt as well, nothing moving... Rolling Eyes

so I've burned it Embarassed

Where do I go from here? I did find a NOS one on line but it was very expensive, This one looks just like new so I wonder if it can be repaired, or maybe I could buy a cheap replacement and use it's innards on mine?
_________________
Aris
Willys M38
1936 Cord Phaeton
1954 Mercury Monterey
1968 Corvette Stingray
1973 Mercedes 350SE
1974 Montesa Cota 247T
1982 Kubota B7100

arisLgr · Posted: Sat Sep 09, 2017 11:09 am Post subject:

Baio here is the pic

_________________
Aris
Willys M38
1936 Cord Phaeton
1954 Mercury Monterey
1968 Corvette Stingray
1973 Mercedes 350SE
1974 Montesa Cota 247T
1982 Kubota B7100


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