I have always in my car, a mini toolbag which is very useful in many cases.
Its a simple shoulder mini bag equipped with several basic tools, in order to give solutions everytime and everywhere , when I have not carry my basic toolcase.
As you can see in photo it contains some screwdrivers, plier, mini cutter, gas soldering iron, knife, torch,insulating tape, a mini multimeter UNI-T UT10, a plastic case with screws, fuses,terminals, connectors and other stuff.
Also inside this bag you can find some wires with crocodile clips, and a multi connector (adaptor) made by myself, with bns/rca/ dc jack/ crocodile clips connected all together,in order to have any combination you want (rca to bnc, bnc to crocodile clips, etc)
This toolbag has "saved" me many times, thats why I use to call it "first aid toolbag"