Black max buzzer schematic?

[mogfisher]

Hey folks. I ordered the oem mercury manual for my 89 150 blackmax, but it's not in yet. I was hoping to get some troubleshooting done on my project boat. I have no beep on startup and I assume no warning beeps either. I've read about the control module but I want to rule out the buzzer first. I pulled apart the controls and found the little sucker. It has the purple and tan wires going to it. I don't remember which was which, but I had 12v ign on 1 of them and around 1.4 volts ign on the other. I assume this is incorrect. Is this just a 12v on/off circuit? Can I just throw 12v and Ground to the buzzer to test if its good? My assumption is yes. I also assume that the 12v ign wire is normal and the other wire is a neg trigger signal to buzz it. I was just wondering if someone could post up the diagram for the buzzer circuit so I can test wires. The wiring in this boat is a mess and needs to be cleaned up quite a bit so I want to make sure things go where they are supposed to go. Thanks!

Adam

 

[j_martin]

Re: Black max buzzer schematic?

You got it about right. The purple wire is 12 volt key on. The tan wire goes through the harnesses to a terminal strip with 2 screws on it high and aft on the starboard side, just over the switchboxes.

The tan wire on that screw fans out to the overheat sensor, which when grounded sounds a steady tone. The other wire goes to the oil alert module, and should ground for a few short beeps when power goes to the oil alert module. If you ground that screw, it should beep.

The other wire on the terminal strip is 12 volts key on for the oil alert. Should be purple.

BTW, the measurements you gave for the buzzer indicate an open buzzer. If it's not sounding there should be 12 volts on both terminals.

You can hook in any 12 volt buzzer, piezo, or light to that circuit. There should be a tan wire in the dashboard harness to the same circuit.

I use a loud sonalert in my dash. I just have to remember to duck when I key on.

hope it helps
John