GPS Module Not Responding

[Tadpoletodd]

Hello All,

Before I make a call to Lowrance I thought I'd give the forums a shot. I have a GlobalMap 3500 and last night while trolling the unit lost satellite reception and I received the following message, "GPS Module Not Responding". I'm desperate as I'm taking a couple family members on a fishing trip this Friday. I've checked all my manuals and can't find any reference to this error. Did my receiver just take a dump? I checked all connections and everything appears legit.

Any information on how to diagnose the problem and fix it would be most appreciated!!!

Thanks, Todd

[Valv]

The GPS antenna on your unit gets power from the unit itself.

Let's do it like you would treat a PC, shut unit off, disconnect power cord (or at least 1 pole) wait 30 seconds then replug everything up and fire it up.

[PerchJerker]

The gps module gets power through the network port on the head unit but there are 2 power leads for the head unit. They were obviously both connected at one time since it used to work, but just be aware that there are two power leads (ie. 2 blacks and 2 reds) if you're tracing power, looking for blown fuses, checking connections, etc. But before you get into all of that try Valv's idea, or try turning off the master power in your boat if you have a master power switch. Good luck.

[Cliff Wagenbach]

I got the same message from mt GPS unit.

Lowrance said to check the plug-in from the antenna to be sure that you have a good connection at the GPS. If you have the extension cable for the antenna to the GPS, check that connection also. (That was my problem!) If it is not a connection, your antenna is bad! Very costly to replace! Around $200.!!

Cliff

[wplatehunter]

I have had the same problem two times and by turning the unit off and unpluging it that seemed to work for me.

[Tadpoletodd]

Thanks all!

I'll be working on this tonight and we'll see what happens. I'll post my results.

Crossing my fingers man!

Todd

[Jim Almquist]

When ever I had the same problem on my LMS350A I had to remove the power and reconnect.With the unit powered up unplug the GPS module cord from the back of the unit and plug back in. Seems like it needed a jump start in order for the unit to start responding again.

[Tadpoletodd]

Well guys, here's my deal. After going through my system tonight I believe I'm narrowing down the problem.

The GPS unit power cord (blue plug) splits into three lines:

1. GPS unit power line

2. NMEA 2000 power line

3. Data line (which I'm not using)

I noticed while going through the system the fuse from the NMEA line was blown. While replacing the fuse it immediately blew again. About three fuses later I discovered that if I unplugged the LGC-2000 cord that goes from the unit to the antenna, the fuse wouldn't blow. As soon as I plugged this line back into the GPS the fuse blew again. I tested that scenario again to make sure it was the case and it was.

Now what?!? Where's my problem? Do I have a bad LGC-2000 cord? A bad LGC-2000 antenna? Or, is the problem in the main power line going from the unit to the battery? That fuse never blew. I'm completely out of ideas here. I also noticed slight corrosion around what I believe is the NMEA power negative pin in the main power blue plug. I noticed a little moisture in the smaller LGC-2000 plug-in as well. Could that be causing the short?

Help please! Any ideas that may help me fix this are welcome.

[PerchJerker]

The gps module is powered all the time, whether or not the head unit is on. That is why the fuse is blowing when you connect the gps module to the head unit. I believe you are correct in that it's between the head unit and the gps module.

The corrosion and moisture you noted could be the culprit, these units are very sensitive so it's probably a good spot to start. If you can't solve it by getting rid of the corrosion the next step might be to try a slightly larger fuse (I assume you're using 3 amp fuses). After that I'd move on to trying to test another gps module on your network if possible, or try your module on someone else's network if possible.

The gps module cable is only 1-2 feet long, if you have a longer extension cable between the gps module and the head unit you could try taking that out if you can get the module and the head unit together without it.

Good luck, you're on your way and I hope you get it nailed.

[uglystick007]

You want to go to Lowrances self help pages. You will need a multimeter. They have pictures and pinouts for trouble shooting this problem. Start with their NMEA 2000 Network Troubleshooting Guide.

[Tadpoletodd]

I feel like I'm close to figuring this out; with everyone's help of course.

I am using 3-amp fuses and going through quite a few of them I might add. I'll try a 5-amp and see if that works. If not, I'll remove my module extension line and hook the module direct to the back of the unit.

I only have a few more nights available to figure this out. Whew...the pressure is on!

[ice-man/vexilar-king]

Tadpoletodd

Be carefull when you up scale the fuses you could have a monster on your hands. Unfortunetly i have allot of problem customers when it comes to Lowrance GPS. The best advice I can offer is to get some Dieelectric greese for all the connectors first, Second check the ground and all wires that may have a wear point from rattleing around in the boat. And finally most of the first post were wrong, the unit does have it's own power supply. You should treat this unit much like a car amp and run as heavy wire to it for power as you cann get by with 8 gauge would be my suggestion. You will notice a link up time difference as well, it will be faster.

[Dandorn]

Quote:

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Tadpoletodd

And finally most of the first post were wrong, the unit does have it's own power supply.

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Please cite where someone has said it doesn't.