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Old 04-27-2021, 12:08 AM
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prostar205 prostar205 is offline
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Low Voltage Alarm (10.3V) - HELP NEEDED

I am in need of some electrical advice. This past winter I replaced both of my batteries, added the Blue Seas battery switch and ACR and added the ProMariner 20A battery charger.

When I de-winterized, I keep getting the low voltage alarm with the volt gauge reading around 10V. My Perfect Pass is also seeing 10.3V.

I checked voltage at both idle and at 1,500-2,000 rpm starting at the alternator, then starter, then battery switch, then ACR, then both batteries - all good with measurements around 13.3 at idle and 14.4v at higher rpm.

Then I figure its the volt gauge itself so I replaced it with a brand new one. That's not the problem.

Then I replace the MMDC (that was not cheap) but that's not the problem.

I am measuring 12.98v between the positive and negative blocks under the helm not matter at what engine rpm is at.

I'm at a loss for where the Perfect Pass and volt gauge are getting their readings from.

Can anyone provide some ideas of where to look next?

The boat is a 2002 X-30 with the Medallion gauges.
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Old 04-27-2021, 12:40 AM
Tsumi Tsumi is offline
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I believe that a significant source of voltage drop is due to the safety switch. Literally all of the power that goes through the on section of the ignition goes through the safety switch.

I did some investigation on our 190. With the key in the On position, there's usually about a 0.5 volt drop from battery to ignition switch. Through the ignition switch is a negligible drop. From ignition switch to voltmeter gauge (I converted to analog gauges) was another 1.5 volt drop. The only thing that I can tell is between the ignition switch and the gauge is the safety switch.
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Old 04-27-2021, 12:44 AM
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prostar205 prostar205 is offline
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Quote:
Originally Posted by Tsumi View Post
I believe that a significant source of voltage drop is due to the safety switch. Literally all of the power that goes through the on section of the ignition goes through the safety switch.

I did some investigation on our 190. With the key in the On position, there's usually about a 0.5 volt drop from battery to ignition switch. Through the ignition switch is a negligible drop. From ignition switch to voltmeter gauge (I converted to analog gauges) was another 1.5 volt drop. The only thing that I can tell is between the ignition switch and the gauge is the safety switch.
By safety switch, you mean the switch under the throttle lever that cuts power to the fuel pump when you remove the red lanyard with the plastic plunger thing?
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Old 04-27-2021, 09:57 AM
Tsumi Tsumi is offline
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That will be the one.
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  #5  
Old 04-27-2021, 11:10 AM
bdiesel bdiesel is offline
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Another thing to check would be the inline fuses for the 12v constant and 12v switched feeding the MMDC. I had a similar issue several years back where I would get a low voltage alarm and loose power to all of my gauges. The fuse and holder contacts were corroded. Cleaned the contacts and installed new fuses and it solved the problem. Been a while since I've been under the dash, but best I can remember, 12v constant was a red wire and 12v switched was purple.
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Old 04-27-2021, 06:21 PM
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Quote:
Originally Posted by bdiesel View Post
Another thing to check would be the inline fuses for the 12v constant and 12v switched feeding the MMDC. I had a similar issue several years back where I would get a low voltage alarm and loose power to all of my gauges. The fuse and holder contacts were corroded. Cleaned the contacts and installed new fuses and it solved the problem. Been a while since I've been under the dash, but best I can remember, 12v constant was a red wire and 12v switched was purple.
Thanks - I'm going to check that tonight. The only gauge I've lost power to is the volt gauge and only occasionally over the last 2-3 years. Hope this could be my problem - easy fix.
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Old 04-28-2021, 09:47 AM
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Quote:
Originally Posted by bdiesel View Post
Another thing to check would be the inline fuses for the 12v constant and 12v switched feeding the MMDC. I had a similar issue several years back where I would get a low voltage alarm and loose power to all of my gauges. The fuse and holder contacts were corroded. Cleaned the contacts and installed new fuses and it solved the problem. Been a while since I've been under the dash, but best I can remember, 12v constant was a red wire and 12v switched was purple.
Went down the boat last night, cleaned the contacts on both fuse holders and it's still doing the same thing. I'm out of ideas at this point. Going to call a boat mechanic that knows these boats and their wiring setups.
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Old 04-28-2021, 11:21 AM
bdiesel bdiesel is offline
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I hate that didn't wind up being the problem, but at least you ruled those connections out. Before you turn it over to someone else you could pull the 24 pin connector from the MMDC and verify voltage on pins 12 & 24, and 11 & 24 with key on(see attachment). Be a quick and simple check.

Perfect pass gets power, RPM, and paddle wheel speed through a separate harness behind the kick panel. You should be able to narrow down pretty quick where it's getting power from. Since PP & the volt gauge are showing the same voltage I would lean towards tracing the problem through the PP feed for direction.
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File Type: pdf masterPackard_24-pinHoriz2004.pdf (27.3 KB, 35 views)
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Old 04-28-2021, 12:50 PM
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prostar205 prostar205 is offline
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Quote:
Originally Posted by bdiesel View Post
I hate that didn't wind up being the problem, but at least you ruled those connections out. Before you turn it over to someone else you could pull the 24 pin connector from the MMDC and verify voltage on pins 12 & 24, and 11 & 24 with key on(see attachment). Be a quick and simple check.

Perfect pass gets power, RPM, and paddle wheel speed through a separate harness behind the kick panel. You should be able to narrow down pretty quick where it's getting power from. Since PP & the volt gauge are showing the same voltage I would lean towards tracing the problem through the PP feed for direction.
Thank You - I will try that tonight.

One question - is the rendering of the connector in the attachment shown on the MMDC side or wiring harness side?
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Old 04-28-2021, 02:10 PM
bdiesel bdiesel is offline
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Should be the harness side. I believe the pins are numbered too, but may have to take a pic and zoom in to be able to read them.

Where did you get your voltage gage from? My fuel gage needs replacing and MC parts depot is the only place I've found one. They think a lot of it to say the least.

Last edited by bdiesel; 04-28-2021 at 02:31 PM.
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