Splicing different gauge wires

[regal68]

Hi, I've been replacing my ~10yr old stereo head unit. I've got everything out and am trying to figure out the wiring. My old molex connector won't fit into the new stereo so I need to splice wires. The problem is the wire in the new molex connector seems to be about 18 ga while the old wires are much thicker (12ish ga).

I'm not comfortable soldering wires that small or cramped in my car. My question is whats the best way to splice the wires other than soldering? I was hoping to use scotch locks but I'm almost positive the wires are more than 2 ga apart and AFAIK they wont work this far apart. The only other option I know of is crimping. Is it possible to crimp properly without a special crimping tool and how can I determine the right size of crimp since they are so far apart.

If it matters, its out of a 2001 Nissan Altima. The old head unit is a Sony CDX-L510X and the new one is a Pioneer DEH-X5500HD.

EDIT: The two molex connectors have the same color wires except the old one has a solid blue wire that says "ANT REM MAX 0.1 A." This blue wire does not connect to anything, is it anything important? Heres a link to the old stereo's manual if that helps. https://docs.sony.com/release/CDXL510Xinstall.pdf

Click to read more...

 

[Milk Mayne 10+ year member]

Cut the wiring harness (for the car, not the radio) off the old head unit, and splice it to the wiring harness that came with the new head unit. Soldering would be best, but butt connectors will do the job. Just don't wrap the wires around each other and use electrical tape.

 

[regal68]

Sounds good. Can I crimp with wrench or should i buy a crimping tool? And would heat shrinkable connectors help to fit the different size wires?

 

[bmk6795 10+ year member]

just get some butt connectors from your local audio parts store, get the smallest size that both wires will fit in and use vice grips to crimp them.