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My cousin replaced a instrument panel cluster of a car with another one that is very similar. He did it by cutting the original junction/wires block that come out of the instrument panel and attached the junction block/wires of the new cluster to the wires by twisting them together and insulated with insulating electrical tape.

Would it be better to solder them and insulate?

21

While the twist/tape method will make the connections and work, I tend to leave this for the quick fix. Over time, with the everyday vibrations occurring, this method tends to allow for continuity issues and things stop functioning.

Another easy type fix is wire nuts. This takes very little time, is more secure than the twist/tape method, and doesn't require any special tools. Like the twist/tape method, wire nuts can loosen up over time and come lose, but would usually last longer than the twist/tape method, plus while the nut is in place there's virtually no chance of a stray wire poking out and causing grounding issues. (Added from a comment by Nate Eldredge ... thanks for the add!)

An intermediate type fix is to use crimped butt connectors. When done correctly, this method has great longevity, but may have issues down the line. They are not impervious to vibrations or poor application. This requires the use of crimpers and the butt connectors themselves, so take a little more time than the twist/tape method. Also, the quality of the butt connectors has a large bearing on the finished product.

The far better method for a permanent fix is to solder and heat shrink application. This takes a little bit of skill, some additional tools (soldering iron), and some time. When done correctly, the connections are usually permanent and there aren't any further issues with them.

All-in-all, there's no wrong way to do it as long as there's a connection and what you are fixing works in the end. I'd suggest there are better ways of doing it, which I think I reflected in my write up.

  • For under the dash ie permanent then soldering is best : repaired wiring looms damaged by fire and end result looked like original (my mentor would accept no less...)... – Solar Mike Oct 21 '17 at 15:44
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    Somewhere else in between is wire nuts. Better than tape, worse than crimp, doesn't need special tools. – Nate Eldredge Oct 21 '17 at 20:55
  • @NateEldredge - Great add! Included in answer. Thank you :o) – Pᴀᴜʟsᴛᴇʀ2 Oct 21 '17 at 21:26
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    I’ve put large diameter shrink tubing over wire nuts to keep them sealed and secured. – IconDaemon Oct 22 '17 at 1:11
  • @IconDaemon if I understand what you suggest, it might not prevent the wires from getting lose unless the tubing is tight enough against them – clabacchio Oct 23 '17 at 9:11
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@Pᴀᴜʟsᴛᴇʀ2's answer is excellent. But, I'd like to add: rather than just twist & tape, there's something called a "lineman's splice," or "Western Union splice" which provides a great electrical connection as well mechanical strength, and is easy to do. (see Wikipedia's illustrations., or google "lineman splice" or "Western Union" splice - there are a few good videos on Youtube.)

The technique gets its name from its use in repairing telegraph and phone wires. If it was strong enough for wires out in the elements, strung between poles over many miles, it's probably strong enough for your instrument cluster.

In my experience, this holds up better than twist caps, and you won't wind up with the situation where you've twisted the cap on, and the wire breaks or one of them is miraculously not secured inside the cap. And, this doesn't require any special hardware.

This is more common with solid-core wire than stranded, but it works just as well for stranded wire.

MakeZine.com Western Union Splice

( from Wikipedia)

The idea is:

  1. Strip about an inch of insulation from the end of each wire.
  2. Slip a 1" piece of heat shrink tubing over one of the wires. Do this BEFORE connecting the wires to each other as it'll be impossible later.
  3. Bend the wires at 90 degrees half way between the end of the insulation and the end of the wire.
  4. Hook one 90 degree bend over the other, so that the wires are colinear, but the bent parts point in opposite directions.
  5. Twist the protruding bit of each wire so that it winds around the other wire.
  6. Tug the wires in opposite directions to tighten the joint
  7. Solder if you want to- I would - but it's not strictly necessary.
  8. Slide the heat shrink up over the exposed wire, hit it with your lighter or heat gun, and call it a day.

Shouldn't take more than about 10 minutes per wire. If done properly, it'll last longer than the car.

If you don't have heat shrink lying around, you can get it from your local auto parts store for cheap. You could use electrical tape, but I despise electrical tape. It's sticky, melts easy, and just screams "amateur hour."

  • With stranded, I found it was easier and took less space, ie double the thickness instead of 3 times, to splay the strands slightly then push them together and add a slight twist so they did not slide apart - then solder them. Once covered the resulting repair was not so bulky and very effective. – Solar Mike Oct 21 '17 at 19:30
  • @SolarMike that works, but relies on the solder for mechanical strength. For this application, I'm sure it would work fine. – 3Dave Oct 21 '17 at 19:34
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    Anyone else noticed that the end of the wires were drawn in the wrong direction? – Zano Oct 22 '17 at 19:50
  • @Zano ha! Nice catch. – 3Dave Oct 22 '17 at 19:50
  • I'd use this if I had full open access to the wiring, but working in a dash, wire nuts are going to be a lot faster and easier. – barbecue Oct 22 '17 at 21:23
2

Another frequently used alternative, cheap and which requires no special tools, is the screw terminal.

There are various types, perhaps the most common is the two-way one:

Source: Amazon.com

or the one-way alternative:

Source: Acquariofilia facile

In the latter, both wires enter the same end twisted and are secured by the screw.

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