Rewire my 74' Cherokee?

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volkswaben
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Joined: Fri Sep 16, 2016 9:45 am

Rewire my 74' Cherokee?

Post by volkswaben »

Ok folks, so I'm nearing the end of my floor pan repairs :banghead: , and am getting the Jeep ready install my rebuilt 360 into. I wanted some opinions on what I should do with the wiring, as I am leaning towards buying a 21 circuit EZ Wiring kit and rewiring the Jeep. The factory wiring seems to be complete and worked fine as far as I know, and uses the older glass fuses. I am concerned that the factory wiring may not be able to handle the 100-150amp or so alternator that I want to upgrade to. I also plan on installing a winch, lights, and other accessories as radios and such. Do y'all think that a rewire would be beneficial? I really don't mind rewiring it, especially cause I have to re sort the wiring in the engine bay anyway.
1974 Cherokee 360/T15
1979 Cherokee - parts rig/ future project?

SJTD
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Location: Lompoc, Sunland or somewhere between

Re: Rewire my 74' Cherokee?

Post by SJTD »

Alternator output doesn't matter. Your old wiring only carries what it did with the old alternator as long as you put new stuff on new circuits so don't let that be the deciding factor.

It the old wiring's in good shape I'd use it but put the headlights on relays.
Sic friatur crustulum

'84 GW with Nissan SD33T, early Chev NV4500, 300, narrowed Ford reverse 44, narrowed Ford 60, SOA/reversed shackle in fornt, lowered mount/flipped shackle in rear.
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Cecil14
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Re: Rewire my 74' Cherokee?

Post by Cecil14 »

The one thing you need to watch is the ammeter in the dash. A higher amp alt WILL cause problems there. Best bet is to either bypass it, or replace it altogether with a volt meter.

The factory wiring was pretty questionable, and after 40+ years it's even worse. If yours is serviceable, keep it. If it's not, and you want to spend the time/money, rewire it. Down the road you're almost certain to have a lot less problems with a new harness than an old one, but there's the headache up front to deal with. Nothing's free.


aa
1983 J-10 - 4.6L(MPFI)/CS130D/Hydroboost/NV3550/D300/44/44/3.54/Disc-Disc/32s/42 gallon 'burb tank
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tgreese
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Location: Medford MA USA

Re: Rewire my 74' Cherokee?

Post by tgreese »

Unless you had an under-dash or under-hood fire, I'd suggest you keep the original harness. As mentioned, these cars loop the charging current from the alternator to the dash and back, so they can measure the current with the in-dash ammeter. Replacing all the wiring won't gain much IMO, unless the existing wiring has been burnt up. There is a sticky thread on IFSJA with threads about bypassing the ammeter. With a 150A alternator, you absolutely must change the wiring to prevent a fire in the dash. I suggest you connect the alternator charge wire directly to the battery. This is also discussed in that thread. http://www.ifsja.org/forums/vb/showthread.php?t=184890

Image
Above is before, and below is after. Look at the 1975 or later CJ-5 witing harness. This is how it's done with a voltmeter replacing the ammeter.

Mad Electrical has a page about this topic - http://madelectrical.com/electricaltech ... uges.shtml

When you install those heavy-demand accessories, get an auxiliary panel from Buss and mount it under the hood and connect directly to the battery. Then run your fused lines to each accessory. The existing wiring is fine for the existing unmodified vehicle.

With old wiring, the problems you will have are typically grounds and corroded connectors. All you have to do for the grounds is re-seat them, clearing away any corrosion. I suggest a new shake-proof washer and a dab of dielectric grease for every ground connection. For connectors, I suggest a contact cleaner like Deoxit, and again a small amount of dielectric grease. Normally cleaning is all that's needed, but you can service the connector. With a small sharp instrument, you can push the connector out of the plastic shell and replace/rewire or solder the connector to the old or new wire. Here is a thread about wiring that should be helpful - https://www.jeepforum.com/forum/f8/basi ... d-1340134/
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.

SJTD
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Joined: Tue May 21, 2013 12:02 pm
Location: Lompoc, Sunland or somewhere between

Re: Rewire my 74' Cherokee?

Post by SJTD »

Oops. Forgot about the ammeter.
Sic friatur crustulum

'84 GW with Nissan SD33T, early Chev NV4500, 300, narrowed Ford reverse 44, narrowed Ford 60, SOA/reversed shackle in fornt, lowered mount/flipped shackle in rear.
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Topic author
volkswaben
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Joined: Fri Sep 16, 2016 9:45 am

Re: Rewire my 74' Cherokee?

Post by volkswaben »

Thanks guys. I'll take a closer look at the wiring before I decide what to do. On another note, does anyone know what this is tied to the steering column with a shoelace?
Image
1974 Cherokee 360/T15
1979 Cherokee - parts rig/ future project?
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tgreese
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Location: Medford MA USA

Re: Rewire my 74' Cherokee?

Post by tgreese »

Any more wires besides the two yellow ones? Looks like a choke to me.

Image

Could be used to filter noise from the power for radio application or such. An unconventional application, if that's why it's there.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.
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