Hi everyone. It is an ancient Rocky Mountain Instruments monitor so yes, recently found out it needs the homemade one (I posted a request in the off-chance someone had one I could buy). Trying to limp along while building a new panel. All the other functions work on the RMI so, to get by, I just ordered a stand-alone Mitchell oil temp guage and sensor to hold me over. I'm an old varize builder and was amazed I would have to build a sensor....
thanks everyone for the replies.
Mike