Combines 1640 cab relay

Check the oil preasure sending unit (not the bell one that goes to your gage in the cab, there should be one beside it with a 3 wire plug on it.The one in my 1620 went bad an shut the hole combine down!

The relays in the 86 series that I had DID go bad every now and then. Made by Prestolite as I recall. I've not had good service life from Prestolite products. Maybe there is a retrofit you could use like from some other manufacturer other than PrestoliteIJ An IH mech. told me to have all cab switches in the "off" position before turning the key either on or off to avoid an arc from a heavy load to the relay. That did help preserve the relay, but your situation may be different.