Here is the comment that is going to upset a lot, soldering produces a rigid brittle joint subject to failure from vibration..... The aircraft and automotive industry has completely gotten away from soldered connection in wiring harnesses.... Yes I agree soldering is probably simplest in cramped space, but mechanical crimped connections "when done properly" is just as good or better ..Unfortunately there is very few options to do proper mechanical "T Tap" (Western Union Splice ) .... No body seems to make a small wire gauge parallel crimp (gutter) tap....
Now comes the rub for many, the 3M parallel taps maligned in first post is probably simples solution, BUT the are a few thing to consider, 1> proper size connector for splice, 2> put a dab of dielectric grease into connector to seal out moisture and oxygen to prevent corrosion before placing wires in connector, 3> be absolutely sure wires are correctly placed in connector then press home connector spade, 4> put zip tie on the main wire and added wire to prevent strain and vibration on connection, ...NO I DONT LIKE THEM EITHER but if done proper they don't fail... The failure of this type of tap is because people don't install them properly (usually takes a pack of 4 to make one connection because of operator failure) ... Like most wiring connections the failure is not in product but is most people don't install them properly....
IF I were to write a resume, it would read something like 38 years in telecommunication industry and have made a million splices from wire sizes for 24 gauge up to 750,000CM.... And in hobby world I do vehicle wiring jobs.... Below is pic of dune buggy wiring project in process (done about 20 years ago, and everything worked first time and NO FAILURES), and still functioning with no problems today...
