Engine alarm

TimTech

Member
Aug 26, 2013
107
Gibraltar, Michigan
Boat Info
1997 330 Sundancer
Engines
Mercruiser 7.4L MPI Blue Water V-drives
1997 Searay 330 with twin 7.4MPI. The engine warning alarm that used to sound when I put either start switch in the first click (engine not running) no longer sounds. This is happening with both engines. If I press the "test" switch on the systems monitor, an alarm sounds correctly and all the test lights light up. All the rest of my gauges work as expected.


According to the owner’s manual supplement wiring diagram, there are two independent alarms without common circuits associated with each engine. Each port or starboard alarm is wired to the respective positive terminal of the coil and is grounded through either the high water temp switch, low oil pressure switch, or high trans temp switch.
Engine alarm.png

However, I've searched behind the dash and gauges and there is no other alarm I can find other than the one associated with the systems monitor. If there are two alarms and I just can't find them, it is virtually impossible that both independent alarms would suddenly stop working.


The only explanation I can come up with is there is only one alarm and it is associated with the systems monitor (wiring diagram is wrong). Therefore, there must be something wrong with the SEARAY IPX system module located behind the dash. I seem to remember the bilge light on the system monitor coming on when the bilge switch was activated. That no longer happens.


Does anyone have any insight or experience with this phenomenon?
 
With it being both engines, maybe something common like a loose ground?
I thought about that but each port/starboard alarm circuit gets its ground from the respective engine temp/pressure switches. If the ground to the sys monitor was bad, the test function wouldn’t work. I can’t find any common circuit according to the wiring diagram.
 
This seems to be your system,
The wiring you showed is the simple Mercury wiring one buzzer all sensors go to ground
The System Monitor is a seperate harness with individual wires to each sensor.

Both engines AND the bilge monitors you indicated stopped working so not specifically engine related.
Unfortunately looks like the module is bad, however which module?

A three wire connects the System Module to the Display panel
A single "signal" wire to the LED display, so this is a digital control board.

It does not show any connection or where the test button is so I assume that both the test button and the audible alarm are on the display panel?
If so all that proves is the display board has power and all the LEDs work...

It could be a bad signal wire between the System Module and the Display module
If not that its a guess which board actually has the problem
https://owners-resources.searayweb....99_330_Sundancer_Owners_Manual_Supplement.pdf

upload_2020-8-22_11-19-38.png
 
Ah, I think I'm getting a better understanding. The wiring diagram I was referring to was for a non-system monitor setup. Furthermore, the Systems Monitor test switch just verifies the integrity of the lights, power, and horn function of the systems monitor display only and does NOT test the integrity of the System Monitor Module. With this understanding in mind, I will start examining the module wiring.
system monitor module.png
 

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