First, I tried searching on Facebook and did find an Ernest Blackmore.He looks young to me but have a look:
I tried just searching Google for "Ernest Blackmore Ambulance California" and found some people but wouldn't know if any of them are correct.I suggest you try several terms with his name in Google and see if anyone is familiar.Also, try searching on google images: .
Assuming he or Jeanette are still alive I tried searching on telephone directories.I did find some Ernest Blackmore's in other states.There is a Jeanette Blackmore age 72 living in California, but if she married I'd expect a different surname.
Try following the links on that page -- it lists people who might be related to Jeanette and some of those names might ring some bells for you.Also, try some other telephone / address listing sites. There are some sites that will provide personal information for a fee, but they may provide listings that you can follow up without cost.The list below came up on the LA Times from a site called "MyLife":
NameAge Location Ernest E Blackmore68 Oceano, CA Ernest W Blackmore88 Ventura, CA Ernest Blackmore56 Ventura, CA Ernest Blackmore III56 Ventura, CA Ernest M Blackmore104 Westminster, CO
I also tried the newspapers to see if there are any death notices.I tried the Long Beach Telegraph and Los Angeles Times and didn't find anything.You might try some other newspapers for areas you might believe he lived.