How to build wiring/harnesses?

[dolsen]

For crimpers, You need a open barrel crimper.

Any recommendations? Molex wants $500 for theirs

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[Je1279]

Any recommendations? Molex wants $500 for theirs

I got this set from Amazon along with some additional dies. Definitely not professional grade, but it works for my needs.

 

[dolsen]

I got this set from Amazon along with some additional dies. Not professional grade, but works for my needs.

Awesome, I don’t need professional either, lol, just effective. YEARS ago I had a 1990 mustang GT hatchback and did some wiring work and had crimpers that didn’t work well. It’s a big part of the reason I’m so gun shy with electrical lol. I had a ton of electrical issues out of it AFTER I started messing with it. Young dumb and 18-19 at the time

 

[McGuyver]

I have had good luck with this crimper. https://www.amazon.com/gp/product/B07476C1LD/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1
Buy extra terminals and connector housings plus a de-pinning tool/pick. There are lots of videos on depinning various style connectors.
Make sure to orient the terminals in the proper direction when sliding into connector and make sure male terminals go in the male connector/female terminals in the female connector. Use quality wire with the proper insulation. Check Wirebarn.com. I would avoid any silicone sealants as many are acetic when curing. Document your wire colors/functions and pin numbers.
Make sure to use sealed connectors and terminals for exterior applications. Sometimes you can find instructions like these too: https://www.molex.com/mx_upload/fam...ty_automotive_connectors/HDAC_user_manual.pdf
Oh a quality pair of wire strippers makes it nice!
Edit - my Mouser order should be in tomorrow with parts to build cup holder harness and bed light harnesses.

 

[dolsen]

I have had good luck with this crimper. https://www.amazon.com/gp/product/B07476C1LD/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1
Buy extra terminals and connector housings plus a de-pinning tool/pick. There are lots of videos on depinning various style connectors.
Make sure to orient the terminals in the proper direction when sliding into connector and make sure male terminals go in the male connector/female terminals in the female connector. Use quality wire with the proper insulation. Check Wirebarn.com. I would avoid any silicone sealants as many are acetic when curing. Document your wire colors/functions and pin numbers.
Make sure to use sealed connectors and terminals for exterior applications. Sometimes you can find instructions like these too: https://www.molex.com/mx_upload/fam...ty_automotive_connectors/HDAC_user_manual.pdf
Oh a quality pair of wire strippers makes it nice!

Thanks for the links, that molex link is really good, I’ll have to take a deeper look at it when I have a little more time.

I was able to, successfully, pin the BCM connectors for the LED projector swap, I’m certainly a lot more patient and detail oriented now than I was at 18. That’s likely a small job for most on here, but it took me 90 minutes to pin 3 wires lol. Mostly because I don’t fit in the floor board under the a pillar.

 

[antho]

I have a cheap one from amazon that works perfect for what i do. I just wanted one next day so i shot for this one and havent found a reason to replace it.

 

[JScaro]

I have had good luck with this crimper. https://www.amazon.com/gp/product/B07476C1LD/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1

I second this crimper. It's easier for the beginner to ensure a good crimp. The ratching / dies ones are great for a single step crimp but leave room for error.

These tools pictured should get you through any basic wiring job.
I use regular heat shrink for inside the vehicle and premium (stuff with glue) for outside / engine compartment.

This tape I sell, it doesn't leave a sticky residue - OEM stuff.
I don't have the fabric / fleece stye.
https://www.ebay.com/itm/1111436155...SMUbKDetv2UNLHCUCSG/yQ0w8=|tkp:Bk9SR6b-9cGwYQ

 

[antho]

One thing i did figure out, If you buy a connector from mouser. Under the page with the connector is a drop down box named "Customers Also Bought" and it typically has the pins that fit that connector. You can then go based off of that and make sure that it is for the correct gauge wire. If not, You can find the variant within that product.

Assumed Connector
https://www.mouser.com/ProductDetail/Molex/31404-3710?qs=DP/2rgZiyLlhjd/aPlnPnw==

20 gauge terminal
https://www.mouser.com/ProductDetail/TE-Connectivity-AMP/1564324-3?qs=2FIyTMJ0hNmPkw1OMs4/iw==

 

[dolsen]

Geez, I love you guys and all of the great responses I am getting. When I get something in my mind, I become obssessed and won't drop it until I feel I have a high level of knowledge about it. So I love reading through all of this stuff

 

[dolsen]

One thing i did figure out, If you buy a connector from mouser. Under the page with the connector is a drop down box named "Customers Also Bought" and it typically has the pins that fit that connector. You can then go based off of that and make sure that it is for the correct gauge wire. If not, You can find the variant within that product.

Assumed Connector
https://www.mouser.com/ProductDetail/Molex/31404-3710?qs=DP/2rgZiyLlhjd/aPlnPnw==

20 gauge terminal
https://www.mouser.com/ProductDetail/TE-Connectivity-AMP/1564324-3?qs=2FIyTMJ0hNmPkw1OMs4/iw==

Yes that is the connector I bought, that is not the terminal I bought though… hopefully I didn’t get the wrong one

 

[antho]

Yes that is the connector I bought, that is not the terminal I bought though… hopefully I didn’t get the wrong one

Which one did you get? The part numbers vary if it’s a reel or individual pieces. So it could be the same.

 

[Buyer2021]

A few of tips regarding custom harness fabrication ...

To help ensure proper wire length

• If at all possible lay-out and temporarily fasten in place (tape) a wire along the actual in-situ exact path(s) you intend for your harness - then remove and measure length from that
• If your harness involves a number of bundled wires or wires of large diameter, use some sort of tubing that's similar in diameter to your total harness bundle for the routing exercise
• Remember that if you have many bends and a large harness bundle, the bends will require extra length
• If your harness involves sharp bends it can be helpful to mark the location and orientation of those then build your harness on a board with wires laced around nails to replicate that shape (the harness will end-up 'pre-shaped' for the complex route)
• It's a bummer to build a nice harness and then find it's a bit too long, or even worse a bit too short, when actually installed

Insulating

• Certainly heat shrink is most appropriate for insulating individual wires at points of exposure near connectors, but with most proper connectors there will not be any exposure requiring heat shrink
• If needing to insulate connections at very large or odd-shaped lugs, Liquid Electrical Tape (available under several different trade-names) can be effective; note you can build-up thickness with several applications allowing each to 'set' before re-coating; also note that the transition between a large lug can use a combination of Liquid Electrical Tape over the large / odd-shaped portion extending over the cable insulation with an appropriate length of heat shrink covering that transition.
• Avoid common plastic electrical tape and 'friction tape' like the plague they are when building automotive / motorsport / marine harnesses; ignore this advice if you look forward to dealing with sticky, brittle, and cracking messes in your future

Bundling

• Heat shrink is not appropriate for 'bundling' multi-wire harnesses - it's too rigid
• Corrugated split tube wrapped with Tesa Cloth Harness Tape or wire bundles wrapped directly with Tesa Cloth Harness Tape will replicate the neat robust longevity and handling ease of OE harnesses (Tesa tape or an equivalent is what OE's use); as previously mentioned do not use any common plastic 'electrical tape' unless you want a mess over time.

The individual wires / cables

• Don't scrimp on wire, pay particular attention to insulation thickness, temperature rating, and quality
• There's lots of no-name cheap wire on the market and lots of wire with insulation not rated for engine-bay / automotive applications; avoid 'em in favor of reputable, maybe a bit more expensive, maybe a bit more difficult to procure, wire and cable
• Ever uncovered an old wire to see the insulation cracked into short segments? Use reputable automotive wire to avoid that shame
• Don't guess, calculate to ensure you are using the appropriate gauge wire for the load and distance involved

It's relatively easy to fabricate high-quality, robust, good-looking, and good-performing custom harnesses you can be proud of ... use the right components, take your time, pay attention to the details.

All just for your consideration, Have Fun!

 

[dolsen]

A few of tips regarding custom harness fabrication ...

To help ensure proper wire length

• If at all possible lay-out and temporarily fasten in place (tape) a wire along the actual in-situ exact path(s) you intend for your harness - then remove and measure length from that
• If your harness involves a number of bundled wires or wires of large diameter, use some sort of tubing that's similar in diameter to your total harness bundle for the routing exercise
• Remember that if you have many bends and a large harness bundle, the bends will require extra length
• If your harness involves sharp bends it can be helpful to mark the location and orientation of those then build your harness on a board with wires laced around nails to replicate that shape (the harness will end-up 'pre-shaped' for the complex route)
• It's a bummer to build a nice harness and then find it's a bit too long, or even worse a bit too short, when actually installed

Insulating

• Certainly heat shrink is most appropriate for insulating individual wires at points of exposure near connectors, but with most proper connectors there will not be any exposure requiring heat shrink
• If needing to insulate connections at very large or odd-shaped lugs, Liquid Electrical Tape (available under several different trade-names) can be effective; note you can build-up thickness with several applications allowing each to 'set' before re-coating; also note that the transition between a large lug can use a combination of Liquid Electrical Tape over the large / odd-shaped portion extending over the cable insulation with an appropriate length of heat shrink covering that transition.
• Avoid common plastic electrical tape and 'friction tape' like the plague they are when building automotive / motorsport / marine harnesses; ignore this advice if you look forward to dealing with sticky, brittle, and cracking messes in your future

Bundling

• Heat shrink is not appropriate for 'bundling' multi-wire harnesses - it's too rigid
• Corrugated split tube wrapped with Tesa Cloth Harness Tape or wire bundles wrapped directly with Tesa Cloth Harness Tape will replicate the neat robust longevity and handling ease of OE harnesses (Tesa tape or an equivalent is what OE's use); as previously mentioned do not use any common plastic 'electrical tape' unless you want a mess over time.

The individual wires / cables

• Don't scrimp on wire, pay particular attention to insulation thickness, temperature rating, and quality
• There's lots of no-name cheap wire on the market and lots of wire with insulation not rated for engine-bay / automotive applications; avoid 'em in favor of reputable, maybe a bit more expensive, maybe a bit more difficult to procure, wire and cable
• Ever uncovered an old wire to see the insulation cracked into short segments? Use reputable automotive wire to avoid that shame
• Don't guess, calculate to ensure you are using the appropriate gauge wire for the load and distance involved

It's relatively easy to fabricate high-quality, robust, good-looking, and good-performing custom harnesses you can be proud of ... use the right components, take your time, pay attention to the details.

All just for your consideration, Have Fun!

Thanks for putting all of that time and energy into my knowledge, I appreciate you and will take all of this info to heart

 

[dolsen]

Which one did you get? The part numbers vary if it’s a reel or individual pieces. So it could be the same.

https://www.mouser.com/ProductDetai...1Ad3cHZ5LpA==&countryCode=US&currencyCode=USD

 

[antho]

https://www.mouser.com/ProductDetai...1Ad3cHZ5LpA==&countryCode=US&currencyCode=USD

I’m sure those will work. There are so many different versions that are almost identical.

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