Joined: Nov 14, 2008 Posts: 91 Location: Minnesota
Posted: Sun Dec 07, 2008 8:01 am Post subject: Main Light SW.--Reass and Testing
Every Head/tail light wire on my 52 M38 is burnt to a crisp so I am testing every electrical item before replacement of wiring harness ect.
I was doing a "Pin a to Pin b" test of the main light switch without much success. I pulled the cannon plug open and it smelled burned inside to I pulled off the top and several copper connectors fell out. They all look good and see no burned wires...Where can I get a reassembly and testing diagram for this switch-------Thanks for your help.
There are a dozen versions of the main light switch. Only the first two have a blowup drawing and a list of parts and were originally intended to be repaired or overhauled. They were made by Bendix-Scintilla. The rest since them are throw aways. Yes some have snap rings allowing disassembly and some have crimped or otherwise sealed edges that do not lend themselves to disassembly. The two early style switches are illustrated quite well in your ORD 9 parts manual. Finding those small parts will be no easy chore.
To properly repair any of these switches will take patience and a knowledge of electrical repair techniques. The sliding contacts must be clean, smooth, and snug fitting. The very old wires connecting these contacts to the cannon plug will need to be replaced. Soft or broken springs will need replacement. And during assembly a special electro-insulating grease is used on the sliding contacts. Cleanliness is of the upmost importance during all of this.
If a functioning switch is your only need then I would go with the newest date of manufacture new switch I could find. This includes the current push button type switch that fits perfectly by the way.
Left to right are first Bendix, Second Bendix and early standard throw away.
Jos. Pollak unit.
Inside this is what you see. Note in the left photo at the top area there are dark tracks between the small round contacts and one contact is discolored. These are the tracks made by small copper particles that eventually pile up and cause shorting and overheating of the switch. These switches can be repaired but will often not last very long.
Here is the inside of the first style Bendix switch. This switch id clearly illustrated with a parts list in your ORD 9.
This is the latest push button style which will bolt right in. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
My switch is the early standard throw away type on Wes's picture. The top arm was just flopping about when I bought the Jeep. Disassambled the switch and found the shaft broken inside. Because of the shape of it, it was easy to make another shaft from plastic on a lathe. With a little filing on the end, it was replaced in the switch. Installed the switch in the dash, but not completely, because I was called away and planned to finish it the next day. But a couple of days later we had decided to go for a little ride with my son. On a back road in the nearby village in the darkest section(where else) we had lost all lights and had lots of smoke. Well, the wires burned in the newly repaired improperly connected switch. The wires were replaced, with correct thickness new ones, soldered in.
A new swich cost about 60Euro around here I would buy one if necessary, but the switch works perfectly since, so it is possible to repair your switch. I can send pictures.
The second and third photos above are the unit he is describing. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Joined: Jul 18, 2008 Posts: 639 Location: Melrose, MA and Santa Fe, NM
Posted: Wed Dec 10, 2008 7:22 am Post subject:
The switch on my M38 is the same as GPA's - the third one in the first picture. Now I'm wondering how long mine will last! It looks very similar to current HMVVE light switches but I haven't done any closer examination - only based on my noticing them when I get behind the wheel of them. I confess, from an asthetic point of view, the push-button type does not appeal to me. I imagine that somone makes repros of the lever switch types if the original's can't be found. Or fix it for the time being as GPA did.
I do not know of any reproduction main light switches being made anywhere. There are a very good supply of surplus stocks around. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
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