[bestgenman]

I’m thinking your indicators are mounted in 1/2” holes with an expanding ear to hold it in place.   See if you can pry it out from the front.  Once out,  measure the voltage across the connections, some are 120vac.  Newell may have used a transformer to step 120v to 12V making all the indicators 12v.    The ‘low air” and those associated with engine functions are 12VDC.

They are available from a number of vendors like, Allied, Newark, Digikey and more.  Amazon will surely have them also.  They push in allowing the ears to expand , holding them in place.