Lowrance Power Issue

[ncbass]

Guys,Lowarance 334 on the bow will not stay on. Press the power button and the unit goes black one or two seconds later. Sometimes it will stay on a little longer, but it eventually goes out. Took the unit to work and plugged it up at our displays, it stayed on. So I assume the problem is somewhere in the power cord. Need suggestions on what to do next. Im a “big dummy” when it comes to this stuff, so any help would be appreciated. If it matters the boat is a 06 Puma.Thanks,Brad

[basschaser]

Trace the power cord on the front mount back to the first connection…normally this is a butt connector and they can sometimes work themselves loose. If not just keep following that hot wire and find the loose connection…but I would bet it is the first connector.Good luck.Judd Lasiter

[4Bassin]

I had a similar problem with mine on the bow. It was a voltage drop through the main power switch. I cleaned and clamped the spade connectors at the main switch and it cured a couple of other problems. I always noticed a low voltage on the BP101 dash compared to true voltage at the batteries. Cleaning those connectors cured the problem. A quick way to tell if its low voltage is to look at the voltage display on your Lowrance unit. If its around 11 volts it will die. FWIW, mine would power off when I hit the starter on the big motor to move from one spot to another, it never got as bad as you describe but it eventually would have…

[markdille]

Besides the connections. Take the fuse out and clean the connections there as well. If the fuse looks corroded, replace it. This is a common result of a fuse issue with the Lowrance units.

[Bass Cat Boats]

BCB correct me if I am wrong but the front units get there power from the Acc Switch at the bow plate (next to the lights and trim switchs)Remove the plate and check the connections on the back of the switch. The power is pulled from the switch but the switch does not control the power to the unit. It is just jumpered there.A loose connection there would cause these problem just like you are saying. It may also happen when you turn the Nav lights on or the livewell kick on. Jamey

[Bass Cat Boats]

Good advice here on what to look for. Is the unit the only thing bad or are you having other electric issues?That is correct Jamey. The power cord will go through the clamshell behind the unit and then run over to get power from the accessory switch on the bow. The Trolling Motor panel has to be pulled and it access is right behind the panel.The master power switch gives power to the acc switch and from here the unit should be able to be turned on an off on the unit itself.BCB

[ncbass]

Used a volt meter on the power cable where it connects to the unit. It briefly registered 4 then 5 and then a small spark on the ground from the cable. Now no power registers at all. Does the power cable tie in with other cables or does it run by itself to the battery? Is there a fuse involved?Brad

[basschaser]

Brad -As BCB said in the post right above yours, it gets power from the acc. switch on the front panel. This means no wire running from it to the rear of the boat…directly anyway. Take the front access panel off and start tracing wires…sounds like you have a short somewhere to me if you saw a spark. Look for bare wired areas.It is going to be a pain and be tedious but with some patience you should be able to trace it down. Good luck.Judd

[4Bassin]

Brad, is this unit factory installed? If so the small spark you saw probably blew the Lowrance fuse behind the accessory panel. IIRC there is a indicator light on the acc switch. Does it come on when the switch is on? As far as I could tell on mine there was not a main fuse to the accessory switch, since it fed through the main switch I am assuming it is protected by one of the breakers at the main switch. Again, if low voltage is the problem look at connections. Wiring usually doesnt go bad unless someone messes with it so forget about broken wires and concentrate on something like a corroded connector or possibly a switch that got water inside and is not passing current properly. The fact that your unit would power on and then die indicates it has a connection that isnt loose rather than the voltage is too low to properly operate the unit. Check the voltage at the accessory switch, if low then check voltage at the output of the main switch, if it is good there then the connections between need cleaned, if the voltage on the output side of the main switch is low check the input side of it, if it is low check both sides of the breaker, if it is still low check the connections at the battery. FWIW, if the main switch output is low you should be having problems with your lights, bilge and aerator pumps and other accessories. The voltage drop from the battery should not be more than .5 volt from the back of the boat to the front, if there is you need to find the point of high resistance. Good luck.BTW, do not rule out high resistance on the ground side, the problem may not be the source voltage but the common return. Find a common ground and take all your voltage readings from it. By keeping a common ground for testing you eliminate any chance for error…

[ncbass]

Alright, here we go. I removed the both panels (acc. and trolling motor) and the cup holder. Found the wires from the unit to the acc panel. Acc switch itself is drawing over 13 amps. Traced the positive wire from the switch to the fuse and separated, fuse looks good. Traced the negative to the first splice and tested again with the voltmeter. Still drawing over 13 amps. Continuity (sp) on the wires from the Lowrance plug to the the the first splice (negative) and the fuse insert (positive). Is it common to patch in the NMEA 2000 Power cables with the regular power supply? The negatives are twisted together and spliced to heavy gauge wire running to the Acc switch and the positive is spliced to heavy gauge wire w/fuse and also joins the regular power supply (w/fuse) and attaches to the Acc switch. Brought the unit back to work to double check and it works fine on the power cord from a 522. At this point I dont know what the problem could be. I am going to pull the power cord and check for rub spot that could cause a short and replace the two fuses. The connections to the Acc switch look good and the splice connections look good. I guess the problem may be in the plug that connects to the unit? Brad

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