Did the GPS receiver find satellites and show your position? If so, it’s nothing
to do with cables or connections. Or was it only the trails that isn’t working?
Periodically I start a new trail and delete the old ones. Then everything works by default – nothing else to set.
If your GPS cannot find satellites, it may be time for a new receiver (puck). If that’s the case, a call to Lowrance would be beneficial as they were offering replacements at a discount. I chose to update to the LCG-4000 which locks in faster (even indoors!), isn’t susceptible to the ESD problems of the 3000, and eliminated the “wandering” of the cursor I had with the 3000.