# Cutting up existing wiring harness... is this ok



## willitwork (Apr 9, 2008)

Hi all,
I am trying to simplify some of my wiring harness out of a 2003 ford ranger. I just want to run this by everyone to see if it is ok what I plan to do.

First of all, I do not need the alternator wires or starter motor wires.
I don't want unused wires leading to nowhere.

So my set up is this: the wiring harness I want to cut 'originates' at the main fuse box. There is a red positive wire that 'splits' into 3 directions, one to the alternator, one to the starter and one to the battery.

Is it ok if I 'snip' off the positve going to the alternator and starter and 'cap' that wire by the fuse box.

Or is this possible: I am using an Iota DC/DC converter could I connect the red positive out of the fuse box to the converter. I hate to assume this, but if the converter will be charging the accessory battery is this how the current gets back to the battery from the alternator? (through the alternator wire to the fuse box to the battery). In other words, instead of connecting the positive wire to a non-existent alternator, can I connect it to the dc/dc converter and save the alternator wiring?


For the negative wire that used to go to the engine block, can I just ground that to the frame or should I put that to the electric motor 'cage' (which is aluminum).

thanks for any info. questions may be dumb, but I have to learn.


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## imaspaceguy90 (Dec 14, 2008)

I snipped out all the old wiring from the oringal motor. I simplified it down to what i needed. I kept all the lighting circuits intact. Good luck with the build bud.


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## tj4fa (May 25, 2008)

WillitWork said:


> For the negative wire that used to go to the engine block, can I just ground that to the frame or should I put that to the electric motor 'cage' (which is aluminum).


Grounding that wire to the frame or body of the truck would be ok but I would not advise it on the traction motor casing. Keep the 12V system away from the high voltage system. 



WillitWork" said:


> Or is this possible: I am using an Iota DC/DC converter could I connect the red positive out of the fuse box to the converter. I hate to assume this, but if the converter will be charging the accessory battery is this how the current gets back to the battery from the alternator? (through the alternator wire to the fuse box to the battery). In other words, instead of connecting the positive wire to a non-existent alternator, can I connect it to the dc/dc converter and save the alternator wiring?


 
On my '91 Ranger, I used some of the circuits out of the main power distribution box on the passenger firewall to power some circuits. 

One of your red wires from the battery powers the main distribution fuse panel on the passenger's fenderwell. I used one of the heavy gauge (30A or 40A fused Alternator wires from the main distribution fuse panel to power my DC/DC converter through a relay (see photo below). 

It provided fused +12V power through an Anderson connector to the low voltage contacts of a relay. A similar gauge wire (#10AWG I believe) ran from the negative battery terminal through the Anderson connector on to the -12V terminal on the DC/DC converter. 

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I tapped into a 12V wire that ran around the harness from the driver's side to the starter solenoid (hot with key on) to power my 12V fuse block on my control board that now provides fused power to relays, the low voltage side of contactors, the 12V controller heat sink fan, vacuum pump power, and the inertia switch.

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I tore out the entire harness to the EEIC computer system and probably shouldn't have as there are a few wires that went to it that still provide some 5V input to my dash gauges. 

Because I tore out the computer harness, I have a constant brake light and Rear Anti-lock Brakes System light on and my temp guage and fuel gauge peg out when I turn the ignition on. 

Although I don't have an air bag in my early model...you might. If you take out your computer/harness, then you might also have an annoying air bag light on all the time.

I'd recommend thinking twice before tearing out too much wiring right off the bat but some of the other circuits can be useful.

Control Board 12V Fuse Block










DC/DC Converter Power/Relay


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