24v to 12v QSB conversion /alarms always on

[Dale Lisi]

Converted QSB 5.9 425hp engines from 24v to 12v three years ago, disconnected alarms because they were constantly on for no apparent reason. All information ( oil pressure , temp , load , etc) was accurate and being displayed. The only code that was showing up was “low voltage 13.7” . I was informed that I should change the SIM modules on the engines . I changed the SIM modules and the low voltage code was gone however , when I connected the alarms , they were still going off. Trying to figure out how to remedy this so that I can have alarms.

Topic

[Corey Schmidt]

OK, so if you connect the buzzer… the alarm always SOUNDS?

There a LOT of the silver 1.5 VesselView screens that the internal alarm relay would remain “stuck” and the buzzer never went off… I think I have 2-3 of these units labeled “Stuck Buzzer”…

Not much you can do…..

[Dale Lisi]

No codes

I disconnected the alarm buzzers. There are no codes and everything runs perfect . I have put 3500 hours on these motors and everything is in order except that the audible alarms never go off.

[Corey Schmidt]

The MUS plugs will not affect alarms re: voltage nor will the SIM modules… the SIMs must see 12V at all times… the ECM doesn’t care if 12V or 24V although the calibration may dictate whether it throws a low voltage code or not… that’s easy to determine with a FAULT ID that we can lookup.

Question: When you say “removed alarms”… what does that mean exactly? The engine ECM dictates when the faults present themselves and will be visible on the digital screen(s).

What EXACT alarms are showing when everything is connected? There should be a FAULT ID number associated…

[Dale Lisi]

24-12 v

I will have to get some pics but , I changed the starters, lift pumps, alternators and SIM modules. The motors were previously installed together when they were 24v (one slave and one master) I have them installed where they are not aware of each other. I am assuming that this may be the issue. I did have a cummins certified company do the computer download to change the computer to 12v . I am not sure but I am hoping that one of these plugs is the problem (attached pic)

[Corey Schmidt]

Send lots of pictures of your gauges, etc. so I can see how you’re setup…

What ALL and EXACT components did you swap from 24 to 12V? Be detailed…

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