Installing Alarm Horn on 95-96 Mercruiser

[Pbober]

Hello, My startup alarm horn quit and I purchased a replacement, but unfortunately failed to take a picture of which gauge and specific post the purple wire was connected to. I assumed that it was the oil gauge and the post when the ignition is turned on had power to it. When I hooked it up and turned the ignition on nothing happened.

When I took off the old one I had hooked it directly to the battery to test and it did not work. I did the same to the new one and it in fact did work.

The boat is a Reinell with Faria gauges.

I am pretty ignorant when it comes to electrical systems, so any thoughts or suggestions would be appreciated.

Thanks!

 

[Scott Danforth]

purple is simply the color for the ignition feed. all the purple wires under your dash get the power from the key switch. they are all daisy chained together.

 

[alldodge]

Agree any purple on one side, and the other side goes to the Tan/Blue. It could be your Tad/Blue wire is where the problem is. With key on disconnect the temp sender switch and ground the wire. If it tuns ON, this means its wired right but your oil pressure switch may also need replacing if the wire is not broke

 

[Pbober]

Thanks for the earlier posts.

Okay, so just on a hunch I checked the old alarm again and in fact it did work. So as Alldodge mentioned there must be a problem on the tan and blue side. I put the muffs on and startrd the engine and all gauges are working.

Any suggestions?

Thanks

 

[Scott Danforth]

post 1 says your old buzzer did not work. post 4 says it does now. which is it?

the buzzer gets its ground from two switches, not associated with the gauges at all.

suggest you grab the factory manual and start troubleshooting

 

[alldodge]

Not knowing which motor were working on makes it a bit difficult.
Find the single wire switch on the thermostat housing with a Tan/Blue wire.

Turn key to ON but don't start it. Take the wire off the switch and ground it against the block or another spot with no paint and see if the alarm sounds

 

[Pbober]

Oh, I’m sorry it is a 5.7 Mercruiser. I am pretty sure it is a 1996. Regarding the conflicting post, I must have not have had the battery switch turned on correctly. Sorry for the confusion. There are I think three switches that have a tan/blue wire. I will check all three.

 

[alldodge]

Yes, temp, oil pressure and drive lube

 

[Pbober]

Hello, I grounded out what I think is the temp switch as instructed and sure enough the alarm went off. It did not beep on any of the others. So is my next step to swap out that sending unit and replace it with a new one? Anything special I need to be aware of a far as ordering it? Thanks!

 

[alldodge]

That is the temp switch and no need to replace unless it won't close and sound alarm when motor reaches 200* F

Can test by placing in pan of water with a thermometer on the stove. Connect a ohm meter to the post and the case. If it closes around 200* its good

Your original post was wondering if the alarm works, and it does, at least for the temp switch.

Find the oil pressure switch, its of similar size and is either behind and below the distributor or low, port side where the oil filter lines are. Will be on a Tee fitting with a larger sender which is the oil pressure gauge sender.

 

[Pbober]

Hello, I found what I believe is the oil alarm sensor switch. However instead of a tan/blue wire it had a purple/yellow wire. There is a tan/Blue wire hanging freely but it does not reach the sensor. I grounded the purple/yellow wire and nothing happened, however when I grounded the tan/blue one the alarm sounded.

I should mention that a rebuilt engine was installed by my son three years ago, who assured me it would be very easy for him to pull the old motor and install the rebuilt. Needless to say I spent the last 2 1/2 years with a local marine mechanic who has been correcting several installation mistakes. However the alarm has been working just fine for the last two years. Any thoughts on this quandary? I have attached a picture of the tee with the sensor.

Thanks for your guidance to date!

 

[Scott Danforth]

there are two oil pressure switches in your photo (one on top the tee, one below)

 

[alldodge]

The Pur/Yel goes to the electric fuel pump. The other wire on the oil pressure switch should come from the ignition circuit (Key switch Purple).

The other Tan/Blu would be used if installed on a inboard and would go the the temp switch on the transmission

Depending on your serial number it may or may not have an oil pressure alarm switch. Being TBI if it does then it would have a Blu/Tan wire on it

 

[Pbober]

I thought the top switch was for the actual oil gauge and the bottom for the alaram.

Regarding the electric fuel, the original block had a manual fuel pump and we were unable to find a block with the hole for a manual pump and so an electric aftermarket one was added. Not sure if that has any impact or not.

???

 

[alldodge]

I'm just using the standard colors and how they are wired. Not being there to see what is there I'm using judgement

The gauge sender is larger then the switch. The switch and/or sender can be at either location and can be Tee'd to be placed in the same location

 

[Pbober]

Hello, Finally got back to this project!

I ran a jumper from the oil sending test unit to the the shorter tan/blue wire leaving the purple wire unhooked. With ignition turned on the alarm worked as it was supposed and then started the motor with muffs. Alarm ceased and all gauges were working.

The only other thing I can think of is that I had some oil leaks repaired at the same time I had the boat winterized. My mechanic is pretty experienced but one never knows.

Maybe it’s time for a new boat, I have had this one for twenty two years!

if I find something new I’ll let you know. Thanks for your guidance and assistance.