LCX-18C says, GPS not responding when I power the unit up, everything else works fine.

SOURCE: Lowrance LCX-16ci - screen's gone out

I have a working unit with a bad antenna. Interested?
[email protected]

SOURCE: Lowrance LCX-15MT Ihave used this

Go to lowrance's website and run through their set up tutorial / instructions for the unit, there is also a software upgrade you can do online for the unit.

SOURCE: gps will not turn on lcx 27c

i have lcx 27c gps will not work locked up module not responding but has power to it

SOURCE: lcx-15ct (gps module not responding)

Before you give up on the LGC-12S you have now though, try plugging the LGC-12S right into the LCX-15CT without an extension cable. If the module not responding goes away...you just need a new extension (GPSX-25G p/n 99-46).

The power cable has a set of yellow, blue, orange, and bare data wires. If these wires short together, you can get the module not responding error.

If all that doesn't help...the LGC-12S is bad.

The LGC-12W p/n 112-06 will work with the LCX-15CT. You probably get this at many marine electronics dealers or go to lei-extras.com and buy it straight from Lowrance. They cost $229 so you might want to shop around putting that money into a whole new system altogether.
Make sure you have the latest software updates if you get the newer LGC-12W. These can be downloaded at http://www.lowrance.com/en/Downloads/Product-Software-Updates/

Let me know if you need more help.

SOURCE: was working fine,then i get mess.gps module not responding ???

The "Module not responding" message has nothing to do with the GPS display unit. This is a problem with the antenna unit. The unit is crammed with solid state components. This problem arises when the unit is exposed to direct sunlight. This causes over heating and failure of the antenna unit. The only solution is to replace the unit as Lowrance will cannot repair it. They will however, sell you a new one for around $140.