Solder seal wire connectors for automotive use - worth a try?
They're ok. Im not a big fan of soldier less connectors beacuse they look like crap.
I tested a few when i first found them. It was hit or miss how easy they pulled apart. Never bothered to test resistance on them but its probably close to an actual soldier joint, just not nearly as streamlined.
If you are dripping soldier you are doing it wrong. Use thinner soldier.
The stuff i use is like 1/64 of an inch thick. It melts super easy. I also never use a soldering iron. I use a butane torch that is made just for soldering. Two alligator clips on a short section of solid coper wire is a handy tool for thise hard to reach jobs. O e end goes in each clip and the connection is held nice and straight now you have both hands free to make the joint.
A pair of automatic wire strippers are realy realy nice to have. As is the correct shrink tube and a decent heat gun. (The shrink tube i use is a 3:1 shrink ratio and has glue inside to seal the joint.)
To do it right you need a full on set of some specialized tools but in the end it is all worth it.
90 percent of this will end up under the dash.