I'm surprised that a short or something worse didn't occur with that cable splice with bare wire showing.
In 1971 a friend of mine in Lubbock bought a 1961 lwb Pontiac ambulance from Gold Star Ambulance in Clovis, NM. He paid a whopping $500 cash for the car. It came with a roof-mounted Q flanked by a pair of red two-lamp Dietz beacons that resembled Federal 14s, and there was a clear-domed Dietz 211-WW beacon behind the Q. To this he added: two blue Dietz lollipops between the Q and front beacons; a pair of Federal Fireballs (1 red, 1 blue) over the rear door; a Federal 77GB doubletone siren on the right fender and an SA24 siren speaker on the left fender, powered by an old PA15 Director.
This gentleman was the first, and for many years, only black cop at Texas Tech. He bought the ambulance because there were problems getting an ambulance in his part of town. To meet the requirements city licensure, we used my 1963 Consort ambulance along with his '69 Ford wagon to get his service moving.
The Pontiac came with twin batteries and a high-output alternator, so we never had problems with it when running "hot".
But one Saturday night I had taken the big Pontiac ambulance to the car races instead of using my Consort. I loved driving that big rig, and my friend had police duty that night. That evening a young guy was injured and began to transport him to the old West Texas Hospital in Downtown Lubbock. With the way that car was lit up, especially at night, we had no problems in being seen or heard. But as I was entering the main part of the highway from the access road, I let loose on the Q, and all of a sudden all of the warning lights quit. I let up on the siren and let it roll, and in a minute or so the lights came back up. But the same thing happened the next time I used the siren, so I completed the run using only the Federal Director.
So on Sunday afternoon some of our guys and I met at his house to see what had caused the problem. The lights were powered by two switches: the original switch which ran the beacons and a spare switch on the console which powered the lollipops and the twin Fireballs. There was no problem found at the switch panel, so we followed the wiring from the panel to see where it ran. What we discovered was that all of the wires]that came from the panel were twisted together and shoved up into a "hot" spot on the main fuse block. It's a wonder we hadn't experienced that short much sooner. We undid all of that wiring, and routed each wire up through the firewall to the outside and then straight to the battery. After that there was never another problem. We were just very lucky!