787c2i temp problem

my temperature reading quit working on my 787 the system status says it is disconnected what could the problem be i just added a system link cable so i could use one antenna for two units

Join the crowd, my interlink connects and disconnects all the time. Might be batteries?

i had to send it back there was a bad board in it

The sys Link or the Interlink will not have anything to do with the Temp. On the Interlink issue I would download the latest software for your units and see if that will correct the disconnect issue with your Interlink. On the temp problem I would double check my connection. It would be hard to say if it is the unit or the temp gauge in the transducer. If you know someone that has a unit similar to yours you might be able to try his to see if it is the unit or the temp sensor in the transducer.