This is one of those " I shoulda realized that" type of hints.
OK so you have a bad wire, maybe in a cable bundle, or is it a single wire and you think the connection is intermittent.
In today's technology, the DVM's are great for measuring resistance or intermittents, or are they?
Lets see- Hmmm. The DVM puts out little voltage and a miniscule amount of current. The old VTVM's, 630's, etc. put out a fair amount of current and often a higher voltage. The older ones were much more suitable for putting a current thru an Xistor to find a bad junction, whereas the new ones will find a blatant problem, but not one that appears with higher current flow.
So what do you ask has that to do with bad wiring connections?
Well, a low current and voltage through a wire and the connection -might- find an obvious problem, but for many of the PITA connection problems, toss the new meters into the garbage. An older VOM might also find it- maybe.
But the sure fire method ( OK, well 95+ % of the time- satisfied?) is to put an automotive tail light bulb in the end of the wire to ground and run say, 12V through the wire. Ac or DC- no matter. ( No, a LED won't work. No current draw to speak of).
A bad connection will rapidly heat up with the high current the tail lite bulb needs and the connection will become pretty obvious if its in the end of a cable at the connector. You might even find the end of the wire HOT from the current trying to go through a high resistance connection. (Have you not seen a burned wire connection at a tail light housing where the lamp developed a corroded connection and the wire got too hot and burned off at the connector or melted the lamp socket?).
Think of all those RCA patch cables you tossed when you couldn't find the bad end, or the guitar cables.
This WILL find the problem.
What if the break is in the middle of the cable? Well, feel along the cable and "massage it" as you go. If the lamp lights, you are in the immediate area of the fault. If the cable gets hot, you are likely right on top of the break.
" Massaging" the ends of the cable with a lamp load will show up the fault at the end of the cable to the connector too. Many end and internal breaks will momentarily light up as you shove the wire ends together during "Massaging" the wire.
You need a lamp that will draw a high current to test with. I have even used an automotive headlight at times.
Just remember to see if the wire gauge will handle the current needed by the lamp.
This test is not 100% fool proof, but when you are trying to find the fault in coax,( Like corroded connectors or splices) and you are up in the top of a 150' fir tree, it is awesome. it beats climbing up and down several times.
This works on coax, wire pairs, multi-strand cables, etc.
Its cheap and easy. Go to the wrecking yard and get a used bulb and socket if you are too cheap to buy a new bulb and replacement socket. Hint- buy a "bulk" box of 10 bulbs at the auto parts store generally for less than you pay for a 2 pk. in blister packaging- this gives you spares to carry in your car too. Oreilly's Auto Parts is great for this sort of deal. Check around. (Some places won't sell you anything but a 2 pk and have the same pricing on a 10 PK as you pay for 5 blister packs of 2- so check before you buy.)