Wire Loom Question For a 1961 A1

[madmike]

I placed a question at the end of another subject and should have put it in a new post. So here goes. My March 1961 USMC ordered A1, according to the experts, should have a wiring harness made up with Packard connectors.

My A1 has mostly Douglas connectors. Only the tail lights were changed to Packard and knowing this jeep had rear end damage from an accident while in service, I suspect they replaced the lights at that time.

All the other connectors are metal shielded, including the dimmer switch, horn leads, headlights, engine sending units, etc. What do you think the chances are that this wiring was completely switched from newer style to older style? Would the military have gone to that extent to make a change to the OLDER style? And then add the Packard connectors after that? An engine change on this jeep was done, I believe, in 1966, using the data tag on the engine for evidence, but I do not know when the rear body damage was done, other then before 1973 when it was sold off. The engine components use the Douglas style.

I have not been able to get a definitive answer on when the wiring was changed to Packard on the A1's. Only that "the 60's orders were Packard". My March 1961 order was right at the beginning of the Kaiser ownership.

I may need to order a new harness and would to be certain on which one to order. If anyone out here, like me, has an early 60's A1 I would to know which style yours has. Would appreciate feedback and your knowledge/experience on this subject.....Mike

[wesk]

Hello Mike,

Kaiser took the reins in 1957. The earliest all Rubber Packard m38A1's in my data base are 1962. I haven't nailed down a month yet. 52 to 61 are metal Douglas.

I think it is reasonable to assume the only reason for your rubber Packard connections on the tail lights are because late production tail lights were installed in your m38A1 in the field.

Also Loom was only used in a few places on the m38 and M38A1 harness. The fuel gage wire across the top of the tank and the distributor wire #12 from the firewall to the distributor come to mind. There were more but my mind is on holiday today.

[madmike]

Thanks for the correction on the Kaiser takeover date. I don't know where I got the 3/61 date but I'll throw that out of the data bank in my head and make room for more accurate and useful information.

Also thank you for the information in the data base. That eases my mind on which HARNESS to purchase if need be.

It was mentioned by a vendor, that if you have a short with a 24 volt system, it is like having an arc welder in your vehicle somewhere. I have not noticed that there is fuse protection anywhere in the system. Am I correct in this observation and is there any way to protect against the jeep melting down if left unattended with a short problem? If this was discussed before, I apologize and would like a reference to the link.

[wesk]

The main light switches other then the early Bendix Scintilla units used in 1950/51 have a built in circuit breaker. The only unprotected circuits are the horn, instruments and ignition. A battery disconnect switch or remote master relay are your best protection. You can also insert modern circuit breakers, fuses or the old originals found in the early M38 in those unprotected circuits.

[madmike]

Just so I am clear on the concept, a remote master relay would be something in line that would act like a battery disconnect? And that modern circuit breakers would be available for a 24 volt system?

[wesk]

A master relay would be a continuous duty 24 volt solenoid that you would control with a master switch. The solenoid would interrupt the main battery + cable very close to the batteries. This solenoid must be rated equal to or greater than the maximum amperage used in your system. The difference between a master relay and a battery cut off switch is you must manually operate the battery cut off switch and you just flip the dash master switch to operate the master relay. They both do the same job in the same location.


You can also use a hidden switch or even a key operated switch.

Here;s a source:
http://texasindustrialelectric.com/relays.asp
http://texasindustrialelectric.com/pdf/ ... relays.pdf
The SAS-4401 or -4420 would work ok.




The same folks that made the 24 volt Douglas connector circuit breakers and later the 24 volt Packard connector circuit breakers still make them today.

They are the Klixon Company
http://www.sensata.com/klixon/klixon.htm

They still market the 24 volt Packard connector breakers on this page:
http://www.sensata.com/klixon/circuit-b ... l-9115.htm


This is a manual reset breaker. They are also stocked in automatic reset just like the original.

24 volt electrical systems are very much still in use today by Commercial vehicles, military vehicles, emergency vehicles and civilian and military aircraft.

[G740]

You don't need to got as elaborate as Wes has suggested. Not that it is a bad idea, there is another way. Lots of military trucks used a master disconnect switch in the battery cable. Various types, but all were a simple turn switch to positively disconnect the link between the battery and ground.
I have 3 different types of military master switches in stock.
John

[madmike]

John...Are these military type switches mounted under the hood? Do you have to get under the hood each time you want to switch to off? Or were these located in the driver's area. I was thinking that the glove box might be a good place for the switch. Out of sight but handy to use. The relay type shown by Wes would have you routing a small wire to a toggle in the drivers area. can you do this with your switch? I would like to stay military if possible.

[wesk]

Well the relay system is just as military as the manual cutoff switch. But the choice is yours. The manual switch can go right under the dash near the cowl battery box. You will have to fabricate new battery cables for the run from the +terminal on the cowl battery to the manual switch and from the manual switch to the starter. It's no big deal and often depending on where you put the switch the original starter cable will reach the switch and you'll only need to make up a short one up to the battery.

If you really want to go all military then you disconnect the battery ground cable everyday just like we did during my 22 years with Uncle Sam.

Otherwise you can buy all the parts for both systems from military surplus or brand new civilian sources and it won't make any difference since you will be hiding it all from any prospective thieves anyway.

[madmike]

Yes. Hiding it is one of the considerations so it cannot be easily jumped. I will study this some more when I get the tub back on and do my final wiring. Appreciate the information and variations possible.

Mike

[GPA]

Madmike, check out the installation of the Master Switch on the dash of Nekaf M38A1. They were standard on those and with the battery cutoff switch is not only a short/fire prevention, but you will get a theft protection in the same time.