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Mercruiser 2000 43 Electrical question

moondrifter

Regular Contributor
There is a voltage drop of 1 v

There is a voltage drop of 1 volt at the console. Everything checks out. The buzzer works but has a .75 ohns reading.(disconnected) Anyone know what this should be? It runs and charges fine.
 
"If the drop is measured using

"If the drop is measured using the battery positive as the reference point and you're measuring to various other points at the dash, you'll usually have some resistance in the main harness. You don't want a lot (less than an ohm) but it takes two to tango so you'll need to reference to the battery negative terminal and measure all of your grounds, too.

All power measurements refer to the battery posts, not the cable clamps. If you have resistance, clean the battery terminals, check the plug to the boat/motor harness and make sure everything is clean and tight at the ignition switch, power distribution and ground buss.

The buzzer will make no difference- it's a piezo-electric element and doesn't act like a dynamic driver, which is what a regular speaker is. The load is generally stable across the frequency range. That's not causing the drop. It's only in-circuit when the button is pressed."
 
"This buzzer is the ignition o

"This buzzer is the ignition on buzzer, it is activated by low oil pressure,high water temp.ect. I have checked almost every guage including the tack. Was just wondering what the ohm measurement spec is.Could it be drawing while just sitting there, the .75 ohn means something but I don't know what????

Thank You"
 
"Carl:

Although a 1 volt dr


"Carl:

Although a 1 volt drop in voltage seems to be a problem, it sounds like a simple corrosion issue at a connection or an internally corroded wire. Start by cleaning the battery terminals and trace the drop from there. Clean connections as you go. It should be easy to find.

Look at the back of the gauge console. A gauge reading out of tolerance will do it. Look for a fried mini resister or filter coil on a gauge.

If your battery cables are 10+ years old and have have alot of corrosion on the terminals, measure the voltage drop from the battery to the end of the cable. Replace the cable if it has more than a 0.20 volt drop. If you find another terminal with a similar drop, replace the connector on each end and solder the connection. Retest for a drop. If there is no change, replace the wire.

If the boat has 15-20+ years on it in a salt environment, consider replacing the entire wire harness. That's what I did due to corroded wires all over the place. Get busy looking.

Guy"
 
Thanks Guy.The boat is 7yrs ol

Thanks Guy.The boat is 7yrs old. I have checked like you said and it is looking good up to the guages. The voltage at the volt guage is accurate 13.2 . If the buzzer is going to ground that could be the draw. But like Jim said it should make no difference.
Thank You- Carl
 
"Carl- an Ohm is the name of t

"Carl- an Ohm is the name of the units for measuring resistance.

What is the actual problem? Is the buzzer on all the time? That means there's a short somewhere and it could just be the switch. Put the meter on the switch and see if the resistance between the contacts is low all of the time. If it is, that's your cause.

What you really want to do is check for current draw, not resistance of the buzzer."
 
"Jim .The problem is there is

"Jim .The problem is there is a voltage drop at the dash. 1 volt. The manual say's to check switchs for on,off and leakage.I did Ign sw, safety neutral, stop/start all OK.
While testing the Audio Warning System,(new style) I found a .73 reading across the (disconnected) buzzer.That could be a draw. The manual has no mention as to this measurement."
 
"The buzzer should only come i

"The buzzer should only come into operation with the ignition key on, engine running and a sender indicting a failure.

Is the dash instrument panel a printed circuit board or directly wired gauge system? A dirty connector at the printed board may be corroded. Pull it off and clean the board pins with an eraser and inspect the pins on the connector for corrosion, bent pins, etc.

The board may have a cold solder joint that is high in resistance. Look for dull solder joints and resolder them with rosin core solder. All should be shiney.

If it's directly wired, check all the nuts on the gauges for corrosion and tightness. Still a drop in voltage? Disconnect each gauge one at a time and see if the drop disappears. When it does, you found the problem."
 
"Check the rest of your boat s

"Check the rest of your boat switches for leakage; lights, bilge pump, etc."
 
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