# GPS/Trim Tab Problems



## ElLobo (Sep 14, 2020)

Been having some issues with my trim tabs stopping functioning completely (Lencos) or just my port tab stopping functioning. Replaced the actuators and the dash buttons and it helped for awhile but the gremlin has come back. When they do work and I press one or both trims tabs up or down my Simrad Evo3 will dim or shut off entirely and reboot when the trim tab button is pressed. Checked all wiring and fuses are not blowing. My Simrad is wired to turn on when the battery switch is turned to on. I can fix the problem on the water by pulling and putting the fuses for each back in but it seems like I may be getting too much power somewhere in the system or corrosion at the fuse box possible or possible the auto retact on the trim tabs causing too much electrical pull? Everything is fused to the correct amperage. Any advice is appreciated.


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## Smackdaddy53 (Dec 31, 2012)

I’d use the existing wire to pull new wire and change the fuse box if you think there is corrosion causing voltage issues. I had the same issue and after pulling new wire I stripped the old duplex wiring and found internal corrosion that had eaten the copper up. Apparently Maverick did not believe in using marine tinned wire 22 years ago. All it takes is a tiny crack in the outer sheath and saltwater will leach inside and corrode the copper. Same for the ends of the wire where there is any place for saltwater intrusion. Just the damp, humid air can pull into the wiring and ruin it.


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## ElLobo (Sep 14, 2020)

Smackdaddy53 said:


> I’d use the existing wire to pull new wire and change the fuse box if you think there is corrosion causing voltage issues. I had the same issue and after pulling new wire I stripped the old duplex wiring and found internal corrosion that had eaten the copper up. Apparently Maverick did not believe in using marine tinned wire 22 years ago. All it takes is a tiny crack in the outer sheath and saltwater will leach inside and corrode the copper. Same for the ends of the wire where there is any place for saltwater intrusion. Just the damp, humid air can pull into the wiring and ruin it.


You mean wire from the tabs or the Simrad or Both?


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## Smackdaddy53 (Dec 31, 2012)

ElLobo said:


> You mean wire from the tabs or the Simrad or Both?


Start at your battery and work your way through the system. It could be as simple as corrosion at the battery shutoff switch or a bad ground somewhere.


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## ElLobo (Sep 14, 2020)

Smackdaddy53 said:


> Start at your battery and work your way through the system. It could be as simple as corrosion at the battery shutoff switch or a bad ground somewhere.


Got it, thanks Smack!


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## Smackdaddy53 (Dec 31, 2012)

ElLobo said:


> Got it, thanks Smack!


Lots of these electrical issues end up being bad grounds but the leaching of moisture into wiring is also a common occurrence. One boat I was working on had issues with voltage and it ended up being a bad positive terminal af the battery. Another was a main fuse had corrosion on the blades and cleaning it off resolved the issue.


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## C_Wheeler (Jan 14, 2014)

Are the simrad and trim tabs fed by separate wires from the panel or is one jumped off of the other? Tabs pull a considerable amount of juice, and that definitely sounds like an overdraw/bad ground issue. As smack said, even if they are wired separate take a look at the wiring. It may look fine on the outside but be completely corroded inside. I just did a complete rewire on my boat. It was very surprising to see wires that looked great on the outside but be completely corroded away when cut open, even 10+ feet from the nearest splice or connector.


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## ElLobo (Sep 14, 2020)

C_Wheeler said:


> Are the simrad and trim tabs fed by separate wires from the panel or is one jumped off of the other? Tabs pull a considerable amount of juice, and that definitely sounds like an overdraw/bad ground issue. As smack said, even if they are wired separate take a look at the wiring. It may look fine on the outside but be completely corroded inside. I just did a complete rewire on my boat. It was very surprising to see wires that looked great on the outside but be completely corroded away when cut open, even 10+ feet from the nearest splice or connector.


They are on separate wires from the panel. I'm going to pull it all apart tonight and will update as to what I find/hopefully fix.


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## lemaymiami (Feb 9, 2007)

The quickest way that I know to check any wire is use an ohm meter to check for continuity or voltage drop. An inexpensive multimeter and a bit of learning on You Tube might be just the ticket... Note.. I also keep a wire testing jumper cable (just a good length of 14 ga wire with a strong alligator clip at each end) that you can attach to the end of any wire your tester wires won't reach. Very handy when checking to verify each individual wire is actually good inside where you can't inspect (also a must have when chasing wire runs on boat trailers...).


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## flyclimber (May 22, 2016)

I have the same issues. What size is your battery? My 25 hp 2 stroke doesn’t have an alternator so my little battery just slowly dies as I use it more and the trims tabs startup takes a bunch of amps to start.


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## ElLobo (Sep 14, 2020)

flyclimber said:


> I have the same issues. What size is your battery? My 25 hp 2 stroke doesn’t have an alternator so my little battery just slowly dies as I use it more and the trims tabs startup takes a bunch of amps to start.


Odyssey PC1200 battery. Rewired the trim tabs last night and it seemed to have fixed the issues. No more flicker/dimming of the Simrad. Still want to test with the boat in the water running under load to see if it's truly fixed.


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## MercMan (9 mo ago)

you have plenty of battery for sure


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