Wiring/Fuse question

Forgive me for likely a simple question but I am not on my game when it comes to wiring and how everything works. Went out this morning and about 20 minutes into fishing lost power to my trolling motor and front depth finder. Brother in law as in back and the finder back there was still working and they are on the same battery. He mentioned it might be a fuse and sure enough when I got home and tried to pull the fuse cover off it wouldn't budge. After some prying I managed to finally get it loose only to find the fuse was fried....it actually melted into the housing.

First of all is there anything in particular that would cause this and secondly, should I just cut wires and splice a new fuse holder in there? Thanks in advance for the help

The DF should not be on the same battery as the TM or you will get a lot of interference from the TM. The TM is the only thing that should draw enough current to melt the fuse holder so I would look there. Was that fuse for both the DF and the TM?? Is so you either don't have big enough fuse for TM, hence it melted or, you don't have any protection for the DF. The DF should only have about a 5 amp fuse for it(check owners manual). My 12 volt TM has a 50 amp fuse on it.
Good luck, electrical problems can be tricky.

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Originally Posted by SeaRay

The DF should not be on the same battery as the TM or you will get a lot of interference from the TM. The TM is the only thing that should draw enough current to melt the fuse holder so I would look there. Was that fuse for both the DF and the TM?? Is so you either don't have big enough fuse for TM, hence it melted or, you don't have any protection for the DF. The DF should only have about a 5 amp fuse for it(check owners manual). My 12 volt TM has a 50 amp fuse on it.
Good luck, electrical problems can be tricky.

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There are two different fuses back there and I assume one is for DF and the other for TM. One was fine and the other was melted. So should I move the DF's to the battery I use for cranking the motor and leave the TM on a battery by itself?

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Originally Posted by Bluesraider

There are two different fuses back there and I assume one is for DF and the other for TM. One was fine and the other was melted. So should I move the DF's to the battery I use for cranking the motor and leave the TM on a battery by itself?

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And also meant to say the fuse currently in it (one that melted) was a 40amp. If it makes a difference the TM is a 12 volt MK Edge 55 (older model)

I would suspect the fuse got corroded and caused that. The only thing connected to the TM battery should be the TM. I would replace the fuse with a circuit breaker.

The main reason for having the DF on the start battery is the interference from the TM. I had a HB365 in the front and accidently spliced it to the TM leads. Every time I hit the TM the screen on the DF was almost unreadable. If yours does not cause that problem, then you could leave it as is. Hopefully the fuse holder was the problem and not a short in the TM.

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Originally Posted by SeaRay

The main reason for having the DF on the start battery is the interference from the TM. I had a HB365 in the front and accidently spliced it to the TM leads. Every time I hit the TM the screen on the DF was almost unreadable. If yours does not cause that problem, then you could leave it as is. Hopefully the fuse holder was the problem and not a short in the TM.

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I am hoping its just the fuse holder because its going to be a mess trying to decipher which wires go to what. Basically all the wiring coming from the front (TM and DF) is separated into +/- at the back with them all connected to a terminal to attach to the battery. I am the second owner of this boat and it has always been wired this way since I got it. Boat has been used several times with no issues and the screen on DF has never seemed to give me any problems. I would like to get them separated for the reasons mentioned above and may have to get someone to check that out for me.

If I did take it to someone would you take to a boat shop or should anyone with electrical knowledge be able to work on it?

I agree with Bill on corrosion causing the problem. You can get a 40/50 amp circuit breaker from Walleyworld in their boating section. Need a couple of ring eyes crimped on to wires. I am going to take a guess and bet that front finder is wired into trolling motor wiring at or close to the front plug. Need to check and make sure it has a fuse installed up there. I would not wire mine that way but like someone else said if your not getting interference you could leave it. Some one with automotive electrical experience should be able to help you out.