Wiring gurus

[krustyballer16]

Ok, for this LS swap I took out all the engine bay wiring up to the plug at the firewall. Kept all the wiring in the cab for lights, gauges, heater, doors, radio and whatever else. And the fuse panel

 

I just want to know how to get power to the fuse panel to use all that stuff without the stock wiring from battery and starter and relays.

 

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[scaleless]

Ha, well, if you didn't cut it already it would be a lot easier!  There are a lot of duplicate wire colors on the bulkhead connector and the wire colors change slightly through the years.  What year is your Comanche? There is one red or red with a white stripe wire that powers the headlight switch and one green wire that powers the ignition switch (and gives 12v switched power to everything else).  Both need to be connected to constant +12v.  I think that's just about it for wires going in.  There's a dark green wire coming out to energize the starter solenoid and a yellow +12v ignition wire for the coil, if you need.  I think that's about it,  unless you want wires for oil pressure/temp senders and such.

[krustyballer16]

I didn't cut anything yet. Just unplugged at the firewall and pulled them out.

I don't think I even need the jeep computer for any thing in the cab, correct? So I don't need anything for it.

I left everything hooked up in the cab and I just need power to the fuse panel so all of it can work as it did.
I'm basically stripping out all the jeep engine wiring and unnecessary stuff out there.

I'm hopefully going to have a Holley doing engine management and everything

1990

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[krustyballer16]

What I really need is a pin out of these 2 connectors so I can eliminate what. I don't need and hardwire the others coming thru the firewall. Get rid of the big bulky connectors.

[schardein]

I can't help with your specific question, but I can make a suggestion:  Keep that connector.  Once you figure out what you don't need, un-pin all the wires you don't need and remove them from that connector.  Then, any circuits that you need to go inside the cab can go through the now "open" ports.  You can even re-use the wire and terminal, just cut the wire and splice a new one on.  Or, buy new terminals.  The wires you add don't need to go into the fuse block; they can come out the inside bulkhead connector and go wherever they are needed.  This way, you aren't feeding wires through a new hole that you drilled in your firewall, with a new grommet.

 

You could also get a PDC (power distribution center- under hood fuse box) from a 91 and up MJ-XJ, and add it to your engine compartment.  Gut it and rewire it for your purpose.  When done, it will all potentially look factory installed.

 

Hope that makes sense.  This is how I did my CJ7 LS swap.  I think the best swaps are the ones that look like a factory installation, rather than a full custom swap with aftermarket doodads everywhere, or worse, a hack job with random wires going everywhere.

 

I also scavenged connectors from the truck the engine came from, and used them in a few places in the engine compartment.  I suggest keeping track of what each wire does, in a diagram, as you do the work.  I didn't, and had to go back weeks later and trace wires to produce diagrams in case I need to troubleshoot something down the road.

[ghetdjc320]

15 hours ago, schardein said:

I can't help with your specific question, but I can make a suggestion:  Keep that connector.  Once you figure out what you don't need, un-pin all the wires you don't need and remove them from that connector.  Then, any circuits that you need to go inside the cab can go through the now "open" ports.  You can even re-use the wire and terminal, just cut the wire and splice a new one on.  Or, buy new terminals.  The wires you add don't need to go into the fuse block; they can come out the inside bulkhead connector and go wherever they are needed.  This way, you aren't feeding wires through a new hole that you drilled in your firewall, with a new grommet.

 

You could also get a PDC (power distribution center- under hood fuse box) from a 91 and up MJ-XJ, and add it to your engine compartment.  Gut it and rewire it for your purpose.  When done, it will all potentially look factory installed.

 

Hope that makes sense.  This is how I did my CJ7 LS swap.  I think the best swaps are the ones that look like a factory installation, rather than a full custom swap with aftermarket doodads everywhere, or worse, a hack job with random wires going everywhere.

 

I also scavenged connectors from the truck the engine came from, and used them in a few places in the engine compartment.  I suggest keeping track of what each wire does, in a diagram, as you do the work.  I didn't, and had to go back weeks later and trace wires to produce diagrams in case I need to troubleshoot something down the road.

This is great advice here and what I would also recommend. Re-purposing factory connections and the PDC is the cleanest way to go. I’ve done stand alone efi from Holley and it’s a great setup. That being said, a lot of you stock under hood wiring will remain. The ecu itself will be deleted but there are some basic things it provided that you’ll need to either get from the new ecu or will need to piece together like your 5v reference signals for map, tps, vss etc. 
Also, I use alldata for all the wiring diagrams and it has everything you will every need to trace down wiring and thin out what you don’t need.

[krustyballer16]

I found a diagram and I rewrote it since its hard to read the printed one.

I think I will keep the connector, but untangle all the wires and use the "dead" wires for anything I might need in the future.

[schardein]

I don't know how much experience you have with the wiring, so I'll add something.  If you look at the second picture in my post above, the diagram of the bulkhead connector. Note that 4 of the terminals are highlighted in orange.  

 

All the terminals in the bulkhead connector are series 56 male/female, 1/4" spade terminals.

The ones highlighted in orange are series 59 male/female terminals, which are 5/16" wide and have a higher current carrying capacity.  Same as used in most headlight connectors.

 

I'm not sure if the MJ/XJ bulkhead connectors have the same thing, but I suspect they do.  Use the 59 terminals for the high current loads, like the main fuse box power feeds.

[krustyballer16]

I'll take all the advice and info I can get.

I probably won't be doing a de-pinning and running new ones.
I just cut all the wires off the engine bay side bulkhead about 6" long and marked which ones I don't need to hook back up and which ones I do. So I may just de pin those I guess so the wires aren't there.

The headlight harness will be hidden.  I got the idea from another ls swap guy. He ran it behind the fender from the firewall to header panel. So that bundle will be gone.
Gonna try to hide the blower motor wires.

[ghetdjc320]

Are you going to use a PDC?

[Limeyjeeper]

Kristy. I mapped every pin on mine. Jeeps wiring color accuracy is pretty shut but it is a good reliable connector. I repurchased probably half the pins. When I get back from Bantam I will send you what I did. I have all the colors. My memory just isn't good enough to recall what I did.

[krustyballer16]

Are you going to use a PDC?

Besides whats under the dash? That fuse block? Or something else?

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[ghetdjc320]

Just now, krustyballer16 said:

Besides whats under the dash? That fuse block? Or something else?

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A PDC is the power distribution center. Not sure about renix years but they were standard starting in 91+. It houses most of the relays and high amp fuses for all the electrical. I repined my 91 pdc and have my sub amp, arb comp, aux lights, aux e-fans and more all running through it in addition to all the factory components (ac, fuse block, starter, fuel pump, headlights, alt power etc)