The problem:
The GPS, VHS, stereo, and lighter sockets all went dead simultaneously. I tested the fuse block pos to negative with a muti-meter and found 3.6v. Then ran a wire to the battery positive through meter to fuse block negative. 12v reading. The switched to battery Neg to fuse block Pos. 12v reading. Now, when the POS and NEG wires are not attached to the fuse block and show 12v, and then when reattached show 3.6, I assume if have a circuit which is sucking power to a point where the radios, VHF and lighter sockets do not have enough voltage to work. I disconnect the VHF which seems to be where the draw is. Now I get 12v on the block terminals, BUT the GPS and stereo still so not work. Head scratching time. I get on a few forums, get a bunch of ideas and potential causes, and then sleep on it.
Here's some learnings for anyone hunting down an electrical gremlin on a boat. The problem is almost always on the ground side of the circuit. And for me, I need to back off and think about all the aspects of the situation and not leap at one possible cause to the next. With the responses on a few forums and a chance to sleep on it, I woke up today with a clear idea of where the problem lay and how to fix it. Any, here's what happened (and please don't put me in the "what an idiot" category given how obvious this answer is):
1. I thought about the ground wiring for the boat. The engine and tilt trim are on their own independent circuits so it is no surprise they work fine when the GPS and radio do not. So, it seems there must be a ground block somewhere where all the circuits except the engine branch from. If I can find that, I can chase the ground wire from the ground block to the fuse block. So I opened the access to the back of the dashboard and there was the ground block staring right at me. I traced the wire to the fuse block, removed the wire from the ground block, and discovered the post to be loose and the connections slight corroded. I sanded and cleaned the contacts, reconnected, 12v power was restored, dielectric grease the connections and I am good to go.
)
Lessons learned:
1. Understand the big picture before producing the multi-meter and diving into the weeds. In my case, why would all three devices (stereo, VHF, and GPS die simultaneously) and why did the other circuits (horn, wipers, pumps, etc) all work fine even though they are fused at the fuse block. The reason is all those other circuits work is that they do not depend on the ground from the fuse block to work. They each have their own breakers at the console. With that said, they do depend on the fuse block ground in order to protect the circuit overall.
2. Do not trust a circuit is delivering full amperage with no or low resistance even though the meter is telling you that you have 12v. The meter reading 12v even when testing the negative/ground directly to battery positive is not enough to determine you have a viable circuit.
3. Do not blame the multiplier electronic devices for a simultaneous catastrophic failure. Unless you were hit by lightning or taser-ed the devices, this just doesn't happen.
Thank you.
The GPS, VHS, stereo, and lighter sockets all went dead simultaneously. I tested the fuse block pos to negative with a muti-meter and found 3.6v. Then ran a wire to the battery positive through meter to fuse block negative. 12v reading. The switched to battery Neg to fuse block Pos. 12v reading. Now, when the POS and NEG wires are not attached to the fuse block and show 12v, and then when reattached show 3.6, I assume if have a circuit which is sucking power to a point where the radios, VHF and lighter sockets do not have enough voltage to work. I disconnect the VHF which seems to be where the draw is. Now I get 12v on the block terminals, BUT the GPS and stereo still so not work. Head scratching time. I get on a few forums, get a bunch of ideas and potential causes, and then sleep on it.
Here's some learnings for anyone hunting down an electrical gremlin on a boat. The problem is almost always on the ground side of the circuit. And for me, I need to back off and think about all the aspects of the situation and not leap at one possible cause to the next. With the responses on a few forums and a chance to sleep on it, I woke up today with a clear idea of where the problem lay and how to fix it. Any, here's what happened (and please don't put me in the "what an idiot" category given how obvious this answer is):
1. I thought about the ground wiring for the boat. The engine and tilt trim are on their own independent circuits so it is no surprise they work fine when the GPS and radio do not. So, it seems there must be a ground block somewhere where all the circuits except the engine branch from. If I can find that, I can chase the ground wire from the ground block to the fuse block. So I opened the access to the back of the dashboard and there was the ground block staring right at me. I traced the wire to the fuse block, removed the wire from the ground block, and discovered the post to be loose and the connections slight corroded. I sanded and cleaned the contacts, reconnected, 12v power was restored, dielectric grease the connections and I am good to go.
Lessons learned:
1. Understand the big picture before producing the multi-meter and diving into the weeds. In my case, why would all three devices (stereo, VHF, and GPS die simultaneously) and why did the other circuits (horn, wipers, pumps, etc) all work fine even though they are fused at the fuse block. The reason is all those other circuits work is that they do not depend on the ground from the fuse block to work. They each have their own breakers at the console. With that said, they do depend on the fuse block ground in order to protect the circuit overall.
2. Do not trust a circuit is delivering full amperage with no or low resistance even though the meter is telling you that you have 12v. The meter reading 12v even when testing the negative/ground directly to battery positive is not enough to determine you have a viable circuit.
3. Do not blame the multiplier electronic devices for a simultaneous catastrophic failure. Unless you were hit by lightning or taser-ed the devices, this just doesn't happen.
Thank you.
