Issue Starting Maxum 2400 SCR

[wiigelec]

Originally Posted by mitcheaton

Im using the ground into the fuse box under the helm for the other lead. Im using the 2400 SCR wiring diagram(laminated one). Its the exact same as to what i have. Im going to test the gauges. I have to believe something shorted. The boat idled fine for 10 minutes. I turned off the engine to check something, went to start again and nothing. The purple wire coming from the ignition switch splits off to all the gauges and then runs to the shutoff switch and then to the starter. I have to believe something in the dash popped but i have been wrong before.

Thanks!

Generally when things are shorted you get blown fuses and or sparks when you touch wires together, which you don’t seem to have which is why it doesn’t sound to me like a short. It sounds like an open or bad connection, probably in a ground wire.

If it were my boat, based on the information you have provided so far, which admittedly may be misinterpreted because doing this over the internet is tough, I would connect a long wire to the negative post of the selected battery and clip one lead of the multimeter to it. Then with the key in run I would put the other lead on each ground connection in the wiring diagram. If you get voltage on that ground connection it is open and not completing the circuit to allow current to flow. Since your not getting dash gauges or starter it’s probably something common to those two circuits, like a ground or return.

Aren’t electrical issues fun! In the business we have a saying: mechanical problems are easy to find and hard to fix, electrical problems are hard to find and easy to fix. Wouldn’t it be something if a ground wire simply came out of a crimp fitting or was loose? We find loose wires and bad connections all the time that cause these kinds of problems, so that’s the kind of thing I’d be looking for, especially since there seems to be an intermittent component to the problem. Go through all the connections and give them a bit of a tug to make sure they’re tight. Good luck!

[mmwjr]

The battery selector switch doesn’t have any negative connections only positive.

[wiigelec]

Originally Posted by wiigelec

I would connect a long wire to the negative post of the selected battery

Correct, which is why I would connect it directly to the negative terminal of the battery itself. The battery that the selector switch has selected to supply power to the ignition switch.

[mitcheaton]

Originally Posted by wiigelec

Generally when things are shorted you get blown fuses and or sparks when you touch wires together, which you don’t seem to have which is why it doesn’t sound to me like a short. It sounds like an open or bad connection, probably in a ground wire.

If it were my boat, based on the information you have provided so far, which admittedly may be misinterpreted because doing this over the internet is tough, I would connect a long wire to the negative post of the selected battery and clip one lead of the multimeter to it. Then with the key in run I would put the other lead on each ground connection in the wiring diagram. If you get voltage on that ground connection it is open and not completing the circuit to allow current to flow. Since your not getting dash gauges or starter it’s probably something common to those two circuits, like a ground or return.

Aren’t electrical issues fun! In the business we have a saying: mechanical problems are easy to find and hard to fix, electrical problems are hard to find and easy to fix. Wouldn’t it be something if a ground wire simply came out of a crimp fitting or was loose? We find loose wires and bad connections all the time that cause these kinds of problems, so that’s the kind of thing I’d be looking for, especially since there seems to be an intermittent component to the problem. Go through all the connections and give them a bit of a tug to make sure they’re tight. Good luck!

Thanks for the tips! I’ll try that today as well. Which ground are you referring to in the wiring diagram? The one at the helm?

[wiigelec]

Do the instrument lights work, as indicated by the switch in the upper right of the wiring diagram?

[mitcheaton]

Originally Posted by wiigelec

Do the instrument lights work, as indicated by the switch in the upper right of the wiring diagram?

They work when switching on yes. I tested a cable to the negative terminal on the battery and then to the ground on the fuse box. No voltage there.

[mmwjr]

Originally Posted by mitcheaton

They work when switching on yes. I tested a cable to the negative terminal on the battery and then to the ground on the fuse box. No voltage there.

Not sure I’m following you. Using a voltmeter you measured between battery negative and the fuse box negative; correct? If all is good you should get 0 volts as they should be connected.

[mitcheaton]

Originally Posted by mmwjr

Not sure I’m following you. Using a voltmeter you measured between battery negative and the fuse box negative; correct? If all is good you should get 0 volts as they should be connected.

Yep, I connected a wire from the negative terminal on the battery to one end of the meter and the other end of the meter to the ground in the fuse box under the helm. 0 volts.

The instrument lights work no problem when i switch them on.

[mmwjr]

Originally Posted by mitcheaton

Yep, I connected a wire from the negative terminal on the battery to one end of the meter and the other end of the meter to the ground in the fuse box under the helm. 0 volts.

The instrument lights work no problem when i switch them on.

This is a good result as it says there is no resistance in the connect of the fuse box negative back to the battery. However you could still have a resistive connection from the fuse box to item at the helm but this can be just as easily checked now that you no the fuse box is a good reference.

[mmwjr]

Have you performed the test of disconnecting the gauges to see if you can get 12V on the I terminal with only the ignition system powered?

[mitcheaton]

Originally Posted by mmwjr

Have you performed the test of disconnecting the gauges to see if you can get 12V on the I terminal with only the ignition system powered?

Hey Mike, i havent done that yet. its my next step. do i just simply need to disconnect purple at all gauges? the connectors are strange. the wires feed into these 3 plastic prongs. im not sure how to disconnect them. ill snap a picture next time im down at the boat.

i did however connect a wire from the b terminal of ignition switch, put that end on one prong of the meter, and then touched the other end of the meter to the ground on each gauge and was getting 12v. not sure if this test means anything.

i need to figure out how to disconnect the wires from the gauges. but i should just disconnect the purple from each? also i have an alarm that runs to purple as well. i assume i need to disconnect that as well?

[mmwjr]

That 3 prong is a push on connector and you can just pull them off to isolate the gauges.

[wiigelec]

If you want to verify the ground wire from the negative battery terminal to the fuse panel measure continuity (ohms) not voltage

[mmwjr]

Originally Posted by wiigelec

If you want to verify the ground wire from the negative battery terminal to the fuse panel measure continuity (ohms) not voltage

Voltage works as V = I*R. Any resistance in the connection will should up as a voltage drop from the panel back to the battery.

[wiigelec]

Originally Posted by mmwjr

Voltage works as V = I*R. Any resistance in the connection will should up as a voltage drop from the panel back to the battery.

Why would there be voltage on the negative wire between the fuse panel and the negative terminal of the battery? And the absence of measured voltage doesn’t verify the integrity of the wire connecting the two. Continuity does.

Either way, since the instrument lights work I don’t think the gauges aren’t working because of a bad ground anymore.

What are those two switches in the start and ignition wires in the center of the wiring diagram? It could be the gauges and the start/ignition circuits aren’t working for two different reasons.

Did I mention how hard this is to troubleshoot over the internet?

[mitcheaton]

Originally Posted by mitcheaton

Thanks for the tips! I’ll try that today as well. Which ground are you referring to in the wiring diagram? The one at the helm?

I did what you said here:

I would connect a long wire to the negative post of the selected battery and clip one lead of the multimeter to it. Then with the key in run I would put the other lead on each ground connection in the wiring diagram.

I only tested the ground at the dash

[mitcheaton]

Originally Posted by wiigelec

Why would there be voltage on the negative wire between the fuse panel and the negative terminal of the battery? And the absence of measured voltage doesn’t verify the integrity of the wire connecting the two. Continuity does.

Either way, since the instrument lights work I don’t think the gauges aren’t working because of a bad ground anymore.

What are those two switches in the start and ignition wires in the center of the wiring diagram? It could be the gauges and the start/ignition circuits aren’t working for two different reasons.

Did I mention how hard this is to troubleshoot over the internet?

Emergency shutoff switch and neutral safety. I replaced the shutoff switch which is where purple is running.

[wiigelec]

Originally Posted by mitcheaton

Emergency shutoff switch and neutral safety. I replaced the shutoff switch which is where purple is running.

So the neutral switch should be in the start circuit, does it crank? If it doesn’t, are you getting voltage through the switch? Voltage to the harness? Where does the wire go after the harness that’s not on shown on the diagram? Are all the starting circuit ground connections intact? How’s your bilge gymnastics? Donated any blood to the bilge lately? Now may be the time lol.

[mmwjr]

Originally Posted by wiigelec

Why would there be voltage on the negative wire between the fuse panel and the negative terminal of the battery? And the absence of measured voltage doesn’t verify the integrity of the wire connecting the two. Continuity does.

Either way, since the instrument lights work I don’t think the gauges aren’t working because of a bad ground anymore.

What are those two switches in the start and ignition wires in the center of the wiring diagram? It could be the gauges and the start/ignition circuits aren’t working for two different reasons.

Did I mention how hard this is to troubleshoot over the internet?

Basic electrical; the negative wire is carrying current any resistance in that path results in a voltage drop across the resistance. With a voltage drop you will be able to measure the difference between the two points. No measured voltage no drop hence zero ohm resistance in the path.

[wiigelec]

Originally Posted by mmwjr

Basic electrical; the negative wire is carrying current any resistance in that path results in a voltage drop across the resistance. With a voltage drop you will be able to measure the difference between the two points. No measured voltage no drop hence zero ohm resistance in the path.

Fair enough