Not sure but some Cub Cadets are the same as Mahindra and have the same Mitsubishi 3 cyl. diesel. I have a Mahindra 2615HST that eats glow plugs about every 100 hours. My 3rd set has now failed (the original set plus 2 sets I bought). Now at 425 hours and for the 4th set I just ordered an upgrade kit which includes new plugs, 10 second timer, and wire. I am told the upgrade kit glow plugs are 10V where the original ones are 8V with a 3 second timer. Apparently a lot of Mahindra customers had problems with glow plugs burning out or they wouldn't have offered an upgrade kit. The original timer supplies 12V to the 8V plugs for 3 seconds every time the key is turned on in cold weather which I think causes the failures.
First is to disconnect the wire that supplies power to the glow plugs and hook up a DC voltmeter to the wire (red to wire and black to ground) then turn on the key and read voltage. You should only have voltage as long as the glow plug light is on then it should go back to zero. If that checks out you need to check your glow plugs. With the still wire disconnected from the 1st plug, remove the buss bar that connects to all 3 plugs and use an ohmmeter between the top of the plug and engine ground or where it threads into the engine. No reading, there is an open circuit (bad plug), Zero ohms is a short (bad plug), They should read some resistance between the top and ground.
NGK makes the glow plugs for mine but they are only available from your Cub Cadet or Mahindra dealer. No one has a cross reference for them. The NGK name is on the plugs but the NGK website doesn't list them nor does NAPA.
Good luck