Splitting wires for newbies

Question

I'm in the process of getting ready to build a car PC running Linux. One of the features I'd really like to incorporate is the ability to record car statistics from the sensors live using ODB2.

Due to the location of where the ODB2 port is on my car (in the dash where the door opens), it'll be pretty difficult to close the door while the cable is plugged in. Therefore, I'd like to split the line further back a bit and route an ODB2 cable to the back of my car to the machine.

I've never done stuff like this before, but I have done a bit of electrical work (ie: switching out switches, plugs, rewiring things). I'm assuming that what I'd need to do would be to cut the existing cable and basically solder all of the internal wires together to both plugs, the one available in the door for mechanics, and the one running to the back for my computer.

Is this what I need to do? How can I put the wires back together again in a nice, insulated fashion?

score 8 · Accepted Answer · edited Apr 23 '19 at 19:10

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I would recommend using inline wire splices. They are available at any auto parts store. Alternatively you can go the inexpensive and more compact (but more difficult) route. To be absolutely pedantic, NASA has a splicing guide, too. Some pictures follow.

Inline splices (option 1):

splicer

Manual wire joining (option 2):

inlineT

edited Apr 23 '19 at 19:10

Glorfindel

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answered May 08 '12 at 03:41

Alex Hirzel

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Those are called 3M ScothLok's no? – Cybergibbons May 08 '12 at 07:58
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@Cybergibbons I have always used that term for these critters, but I may be wrong! These are used in telephony with small-gauge wires. http://cubus-adsl.dk/elteknik/billedopslag/scotchlok.jpg – Alex Hirzel May 08 '12 at 11:58
http://solutions.3m.co.uk/wps/portal/3M/en_GB/ElectricalMkts/ElectricalSupplies/products/scotchlok-wire-connectors/ there are different ones for different applications. A butt splice is just an end to end crimp connector http://www.wiringproducts.com/contents/en-us/d47_butt_splice_connectors.html – Cybergibbons May 08 '12 at 12:15
My only concern with these types of connectors, whatever they are called, is that they take up quite a lot of space. ODB2 is 16 pins, I think 12 are always connected, and you might be able to get away with 8. That's a lot of connectors in a small bundle of wires. – Cybergibbons May 08 '12 at 12:44
Depending on the make of the car, 3-4 wires may be all that are needed. Most inexpensive OBD2 readers only populate the pins they specifically need--this may be a practical way to see which pins are needed. Also, these connectors can be staggered in a harness. – Alex Hirzel May 08 '12 at 13:47
So I essentially have to cut open the insulation on both wires, exposing the bundled individual wires, then solder connectors across to the right wires, then insert the whole thing into the splice connector for protection? – Naftuli Kay May 08 '12 at 16:23
With the first option (the blue inline splice connector shown above) you can simply close the connector around both wires without stripping. They're slick. Here's a video: http://www.youtube.com/user/etrailertv?v=CBGY5XC3Wqs – Alex Hirzel May 08 '12 at 16:55
I can't stand those connectors. They failed on me regularly in auto applications in the past. Now I don't use them. – tyblu May 09 '12 at 04:44
Why is this answer community wiki? – tyblu May 09 '12 at 04:45
Accidentally checked the box. – Alex Hirzel May 09 '12 at 18:39

score 6 · Answer 2 · answered May 08 '12 at 12:31

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If you need to remove your temporary connection, a tap splice might be better. Quick Splice blade

MULTICOMP - 878106 - QUICK SPLICE BLADE

answered May 08 '12 at 12:31

Martin

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score 5 · Answer 3 · answered May 08 '12 at 21:14

The actual problem to be solved is this:

*Due to the location of where the ODB2 port is on my car (in the dash where the door opens), it'll be pretty difficult to close the door while the cable is plugged in.

so the first thing to do is to see whether the OBD2 connector can simply be uninstalled and relocated such that the above problem goes away, without any cable splitting or tapping.

Since there can be only one OBD2 terminal connected at a time, you don't actually solve any problem by splitting the connector. This is strictly for the sake of providing an additional connector in another place, which will never be used at the same time as the original connector.

Splitting wires for newbies

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