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Lengthening Harness

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Old Jun 10, 2010 | 01:07 PM
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Default Lengthening Harness

I've decided to relocate my PCM, so I need to lengthen the wires. I have a couple of questions:
1. What are the wire gauge sizes that run to the PCM connectors (I can't tell just by looking at them)?
2. I lost the link, but there's a vendor that sells the correct GM PCM wire; anyone have a link or two?
3. What's the best splice or splice method to use? A regular crimp splice is kind of large especially after 20 or 30 splices the bundle of wires grows pretty large (I do like the kind that has the low temp solder sleeve and shrink tube all in one). I suspect that laying the two wires parallel, soldering them followed by heat shrink tubing would be the smallest joint. Ideas?
4. I've read that some people have taken an old cut-up GM JY harness and used some of its wires. What year/model/application should I look for if I don't buy new wire?

I pobably need to add no more than 18" to my existing harness.

Thanks,

Andy1
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Old Jun 10, 2010 | 01:59 PM
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Id recommend selling your stock harness and buying one just like you want from Speartech etc. Thats a lot of wires to lengthen. Crimps arent the best and soldered wires can break with bending or vibration.
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Old Jun 10, 2010 | 03:49 PM
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The harness is not stock, but reworked by one of the custom harness vendors. I simply changed my mind on the PCM location hence my need to lengthen the wires.

Andy1
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Old Jun 10, 2010 | 08:22 PM
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1) Common sizes are 18/20ga TXL jacket. But one 100' roll of 18ga and youll be set

2) Most wiring connector/harness vendors sell wire by the foot. Word of warning though, its more expensive than buying your own roll. I use the ebay seller, just search for TXL and youll see him

3) Solder and shrink tube, hands down. Do NOT lengthen all those wires with butt crimps, the first time you bend the bundle, several crimps will pull off. A proper solder job that didnt overheat the wire will be stronger than the wire itself. You wont break them unless you abuse the bundle like folding it over double or running it through sheet metal non-insulated. Solder/shrink tube is the smallest splice possible

4) Wire is wire, unless its obviously damaged or oil impregnated, its still usable. I use mid-late 90's econo FWD cars and S10 trucks for spare connectors, not just to reuse the wire. A new spool of wire should set you back around $30. Its not going to be worth your while to pull a JY harness unless you need the spare connectors

One last thing, add a few more inches to your PCM harness. Moving an electrical piece 18" does not always correlate to adding 18" of length
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Old Jun 10, 2010 | 08:27 PM
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Here is where to get the right type of (TXL) wire.

http://order.waytekwire.com/scategor...20And%20Cable/
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Old Jun 10, 2010 | 10:28 PM
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One suggestion that will help keep your bundle smaller is to stagger your splices.

Pat
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Old Jun 11, 2010 | 11:00 AM
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Originally Posted by Pocket
1) Common sizes are 18/20ga TXL jacket. But one 100' roll of 18ga and youll be set

2) Most wiring connector/harness vendors sell wire by the foot. Word of warning though, its more expensive than buying your own roll. I use the ebay seller, just search for TXL and youll see him

3) Solder and shrink tube, hands down. Do NOT lengthen all those wires with butt crimps, the first time you bend the bundle, several crimps will pull off. A proper solder job that didnt overheat the wire will be stronger than the wire itself. You wont break them unless you abuse the bundle like folding it over double or running it through sheet metal non-insulated. Solder/shrink tube is the smallest splice possible

4) Wire is wire, unless its obviously damaged or oil impregnated, its still usable. I use mid-late 90's econo FWD cars and S10 trucks for spare connectors, not just to reuse the wire. A new spool of wire should set you back around $30. Its not going to be worth your while to pull a JY harness unless you need the spare connectors

One last thing, add a few more inches to your PCM harness. Moving an electrical piece 18" does not always correlate to adding 18" of length
Pocket, All really good advice. Some of those wires look smaller than 20ga to me, but that's just a guess. Using a slightly larger gauge won't hurt and as you suggested, it would be cheaper to just buy one size. I did find that EFI Connection also sells TXL wire.

For the splice I was thinking of these type that already have a low temp solder in them http://www.repairconnector.com/produ...WG-5-Pack.html
I am not liking their size however. Solder and shrink sleeve is sure to keep things small and reliable (no crimp only sleeves for me!). How would you configure the splice? Twist, then solder, always leaves some stiff radial strands that can pierce the shrink sleeve. Any suggestions?

You're probably right about the time and effort to chase down a JY harness to rob from vs. simply buying a spool of $30 wire.

I was simply estimating the additional 18" length needed for the benefit of this thread as a measure of how much I want to extend the harness. Yeah, I'll get the exact location and run either a string or a wire through whatever devious path is necessary to establish an exact length.

Stu Cool, yeah I agree that staggering the splices really helps to keep the bundle from growing to an unmanageable size.

Thanks,

Andy1
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