2003 4.3L warning alarm horn TB-V alpha

[prc03sx195]

Took the boat out to the lake after replacing the battery and + battery cable. Turned the run switch on located on the throttle control. Turned ign switch to on position and continuous horn went off (all is normal). Then turned ign to start and started but the alarm continued to sound. All the vitals seemed good according to the gages. So I taped over the horn to muffle it so we could continue boating. The weird thing is when we were pulling in 3 hrs later I did not hear the alarm. Any thoughts on what is all hooked into this alarm? Unfortunately I don't have a wiring diagram to check this but I am puzzled. Thanks

 

[Bt Doctur]

So I taped over the horn to muffle it so we could continue boating.

A very bad practice.
low/no engine oil pressure
low/none outdrive oil
high engine temp/poor cooling

 

[QBhoy]

Low gear oil is the usual one if it happens from cold. What engine is this again ? Mpi/efi or carb ? The latter only having a small number of things that would sound an alarm.
likely not too clever an idea to ignore an alarm without investigation or worry. They aren’t there for nothing. As you’ll know, I’m sure. Y

 

[prc03sx195]

I am not the type to let an alarm go but when the engine and gages look to be in range I figured it must have been a switch going bad or wire off. The out drive oil was in range in the reservoir, the oil pressure increased with engine rpm, the manifolds didn't get any hotter than they normally do. It is a carb engine so how many parameters are monitored by the alarm? Thanks

 

[QBhoy]

I am not the type to let an alarm go but when the engine and gages look to be in range I figured it must have been a switch going bad or wire off. The out drive oil was in range in the reservoir, the oil pressure increased with engine rpm, the manifolds didn't get any hotter than they normally do. It is a carb engine so how many parameters are monitored by the alarm? Thanks

Gear oil, temperature for sure. The gear oil deserves a closer look. Staining on the tank can often be mistaken for a level. The float can stick or get porous too, occasionally

 

[MichaelBC]

My 4.3 hat three devices connected to the alarm.

- the gear oil level
- oil pressure on the top of the engine near the distributor
- water temperature in the thermostate housing. The switch has a red mark.

If the cable is off then the alarm does not sound. So it is an easy way to test by pulling the connectors one by one and listen when the alarm stops.

 

[prc03sx195]

My 4.3 hat three devices connected to the alarm.

- the gear oil level
- oil pressure on the top of the engine near the distributor
- water temperature in the thermostate housing. The switch has a red mark.

If the cable is off then the alarm does not sound. So it is an easy way to test by pulling the connectors one by one and listen when the alarm stops.

Is the temperature switch the one with one or two wires? Thanks

 

[MichaelBC]

My temperature switch has only one wire. At my thermostat housing there is one sender for the gauge and one switch for the alarm. Both have one wire.

 

[Earl Cordova]

There are actually a lot more than 3 sensors that are monitored by the ECM.
You either need to purchase a code reader or have a shop connect theirs.

The most common fault on mine is the water pressure sensor.
In the 16 years I have owned my boat it has failed 4 times
and the water pump has been serviced every two years.
Others that have failed are the IAC and MAP sensor.

As a side note the three sensors that have been mentioned in this post
have not failed, yet.

 

[alldodge]

Alarm switches have a single Tan/Blue wire

 

[isaacs]

The gear oil reservoir gives me trouble from time to time; it gets crud built up at the bottom. Empty the reservoir and remove it. Put a small amount of carb cleaner or mineral spirits in it and give it a good shake--this should free things up. You can also try shorting out the two wires that go to the reservoir and see if that shuts your alarm up. If it does, you've found your problem.

 

[MichaelBC]

There are actually a lot more than 3 sensors that are monitored by the ECM.
You either need to purchase a code reader or have a shop connect theirs.

The most common fault on mine is the water pressure sensor.
In the 16 years I have owned my boat it has failed 4 times
and the water pump has been serviced every two years.
Others that have failed are the IAC and MAP sensor.

As a side note the three sensors that have been mentioned in this post
have not failed, yet.

The thread says it is a 4.3 L. So I thought it is a carburetor engine with a Thunderbolt IV or V ECU. This would mean that the sensors are not controlled by the ECU but switch the alarm directly. In this case there are only three…..

 

[prc03sx195]

Correct, only three things are monitored by the alarm, this is according to the label on the throttle control. This has no plug in port to monitor engine parameters, it is before that time. My two water temp sensors in the housing has two wires on one and the other has one wire. Thanks

 

[QBhoy]

There are actually a lot more than 3 sensors that are monitored by the ECM.
You either need to purchase a code reader or have a shop connect theirs.

The most common fault on mine is the water pressure sensor.
In the 16 years I have owned my boat it has failed 4 times
and the water pump has been serviced every two years.
Others that have failed are the IAC and MAP sensor.

As a side note the three sensors that have been mentioned in this post
have not failed, yet.

It’s a carb engine. You may be thinking of another variant…like an mpi

 

[MichaelBC]

Correct, only three things are monitored by the alarm, this is according to the label on the throttle control. This has no plug in port to monitor engine parameters, it is before that time. My two water temp sensors in the housing has two wires on one and the other has one wire. Thanks

I would assume that the alarm switch is the one with one cable on port side. The one with two cables on starboard is most likely for the instrument. As mentioned already, my alarm switch has a red mark on it.

 

[alldodge]

Look at the color of the wire