1967 M-715 Rewiring Advice needed

I am looking for advice here for rewiring. I have read various threads here and other places and have gained pros and cons. I have a 1967 M-715 that is in great shape but the wiring is suspect. I acquired an old fire department brush truck that was well cared for (mostly). I am leery of the spider web of spliced wires hear and there. They converted it to 12 volt when they blew the original engine and installed a 283 SBC. I am happy with it and will keep it. The question boils down to which way to go on rewiring: a Painless wiring rewire or modify an M series loom (m35A2 or M151)?

I wish to use the 3 way switch again with the functionality of the blackout lights. There is a keyed ignition that I will also keep. Nice that it makes it more difficult for it to be stolen. Apparently the M151 wiring may be more appropriate since the alternator wiring is on the correct (driver’s) side. But actually having fused circuits with the painless would be a peace of mind too. Thanks for your thoughtful comments.

I might add that the goal is to restore it to mostly military appearance and Functionality.

Quote:

---

Nice that it makes it more difficult for it to be stolen.

---

Now-a-days a stock trucks is pretty hard to steal.
24V can't be jumped easily.
Few youths know how to shift a standard transmission.
While the key can be hot-wired, the starter button on the floor goes mostly unnoticed.

For all the trouble and aggravation in building a harness (time is money), Vintage wiring of Maine makes front/rear harness for the m715.

I keep the floor starter button and put in a key operated battery cutoff switch.

Quote:

---

Originally Posted by kwai

Now-a-days a stock trucks is pretty hard to steal.
24V can't be jumped easily.
Few youths know how to shift a standard transmission.
While the key can be hot-wired, the starter button on the floor goes mostly unnoticed.

For all the trouble and aggravation in building a harness (time is money), Vintage wiring of Maine makes front/rear harness for the m715.

I keep the floor starter button and put in a key operated battery cutoff switch.

---

I agree with the above. If you use a harness from another "M" series truck you will spend countless hours making it conform. I have rewired two trucks and took the Vintage Wiring route. Its not cheap and will still take some thinking but lots easier then a kluged up system.

I'm no electrical guru by any means. In fact I hate it. But a grand for wiring is kind of steep. But if you consider the time to do your own...well then maybe so.

Buying the tools, wire, harness tape, packard connectors and plugs isn't cheap either. You might be able to get by with only the front harness and repair the rear harness.

Quote:

---

Originally Posted by kwai

Buying the tools, wire, harness tape, packard connectors and plugs isn't cheap either. You might be able to get by with only the front harness and repair the rear harness.

---

^ Best bet there if you want to maintain stock appearance and functionality. Could probably repair/replace the rear with bits left from replacing the front half.
... no fuses though.

How close is the 12 volt conversion's charging circuit to the original circuit? Wondering if a stock replacement would be plug and play.

I never priced the materials to wire mine with stock type wire and connectors, probably not cheap though. I rewired mine on the cheap just using standard 10 ga automotive wire for most of it, 12 for relay triggers and 8 for charging circuit/power to fuse boxes.
Less than $200... not counting the 4 days of a week's vacation time I burned getting it done

Quote:

---

Originally Posted by Von

I never priced the materials to wire mine with stock type wire and connectors, probably not cheap though.

---

The "stock" wire is no longer made. It was called "hypelon" or something like that. It was discontinued about 5 years ago from all the electrical suppliers I deal with. I bought a few reels when I got the notice it was going. Maybe something similar replaced it but I never checked. The stock wire was black, very flexible and the insulation soft and weather resistant.

As to the Packard connectors, not cheap and hard to find in quantity. Plus, you need the crimping tool to do it right.

Thread about the wire no longer made

http://www.m715zone.com/vb/showthrea...ghlight=longer

I've done several vehicles with http://www.ezwiring.com and I was very happy every time. Great quality/price.

We rewired mine with a 12-circuit harness from Hot Rod Wires. The only difficulties we ran into had to do with making the turn signal unit on the steering wheel compatible with the harness's GM configuration.

HRW's products seem to be well made, well thought out, and they're priced quite a bit less than Painless.

I have purchased the crimping tool which was 30 bucks or so. The Packard connectors were a buck a piece too. Too bad on the hypelon going the way of the dinosaur.

Quote:

---

Originally Posted by 44willysmb

I have purchased the crimping tool which was 30 bucks or so. The Packard connectors were a buck a piece too. Too bad on the hypelon going the way of the dinosaur.

---

True that. I don't have any "spools" of the correct wire. However, I have purchased some random military harnesses from eBay (not M715 specific). I take the wire that I need, often already having the connector on it. I also have the proper tape, no adhesive, for the harnesses. Also, most of the time, the wire insulation was just fine if you just peel back the wrapping tape and you get to wire that is still in good condition. I usually splice (solder) the new wire to the old, insulate it with heat shrink and then wrap it back up. I was able to repair several "modifications" done to my original harness.

Don, great advice! Going original appeals to me.

As far as I know hypalon wire is still made by prestolite and also by therm o wire. The mil spec number is m13486/1-5. I just bought almost 400 ft for 70 dollars including shipping. It is sold by awcwire.com, eriksmilitarysurplus.com and saturnsurplus.com.

Thanks!

I just acquired a NOS M715 wiring harnass yesterday! I'm so excited.

Saw the pics, I'm in awe you found one!

Unfortunately, when I stripped the old wire out and tried to install my NOS M-715 wiring harness I discovered that it is indeed NOS but to a M-35A2! Crap.

I already answered your question in the other older thread but since who knows what a search of this subject will come up with years from now.

The M35A2 harness will work just fine. It already has the solid state blinker relay plug installed which is a plus. One or two loops of the blinker wires inside the valence should make it fit fine.

Yep the M35a2 harness should work just fine. Some circuits may be a little long and some might be short, but it's not hard to make it work. I helped a buddy use one on a gutted M37 he rebuilt. The key was downloading all the wiring diagrams from the manuals for both and comparing the circuit numbers to see where they go. Because the military tags each circuit with a metal tag with numbers it makes it super easy to figure out were each one goes.

Thanks. Mine does have the blinker already wired in. The wiring schematics are piling up!

I installed a harness from Vintage wiring ........ awesome ..... too easy.

Quote:

---

Originally Posted by teking

I installed a harness from Vintage wiring ........ awesome ..... too easy.

---

Yep, expensive but it works!

It does. I am angling for a new project so all the money I can save here I can reinvest on the new baby!

Update. The front rewiring was completely successful. It starts with the foot starter and no odd burning electrical smell was noted. No issues with the deuce wiring. It only took time to unwrap the loom and rewrap as necessary. And a bit of brain power to make sure the circuits were correct.

I am waiting for Brown Santa to bring the rear harness next.

When the magic smoke stays inside the wires, it is a job well done.

Otherwise, you might need to read up about English wiring procedures:

http://www.mez.co.uk/lucas.html