I was transporting a patient one day in an ambulance that was a bit worn out. While going to the hospital, the sliding door popped open and I couldn’t get it to secure. Then the siren cut out, so the driver was using his horn figuring that they at least had the light bar working. Turns out, not entirely, when we arrived at the hospital we discovered only half the light bar was actually rotating. Lucky for us the patient was unconscious so was never aware of any of these issues. This particular vehicle also had a small window between the driver and rear compartment and once all the doors were shut, there was no way to open the doors from the inside of the patient compartment. We had to wait for the driver to do so. In of itself not a safe situation, plus the A/C sucked if it even worked. This service also had another ambulance that would do a thing the mechanics called vapor lock, which would just shut the engine off at random times, not helpful. It was also equipped with a lighting device on the center of the hood called a Mars 88, it was supposed to wiggle back and forth to get the drivers attention in their rear view mirror, but it was mostly broken. Eventually they just made it a flashing on and off light with no movement.
Yet another service I worked for built their rigs with a mechanical lift to hoist the stretchers, since their main intent was to transport neonatal babies. However they put so much equipment into these vehicles that the transmissions was over loaded and we would burn them out on a regular basis. It also had an on board generator that when turned off would back fire sounding like a shot gun, also not helpful, especially when transporting into poorer neighborhoods. The lift also would rattle while traveling, but on those heavy patients it was a god send. More than once I watched the rear of the ambulance go down and wondered if the lift was even going get them off the ground.
We once used a loaner when one of our rigs was receiving major service and it became quickly apparent as to why the prior company had retired it. You could only use it for one short call, if it was started up cold and then you had to let it sit for a couple hours and cool off before it could be used again. Why might this be necessary? If you ran it to long the dip stick for the transmission fluid would become a geyser spewing transmission fluid everywhere. Had another loaner that bounced like basketball while going down the road and according to our mechanic was leaking gas from so many places that it was likely to erupt into flames at any moment.

1976 Chevy