Evinrude system check warning horn question?

[sutor623]

Hey guys,

I dont have much experience with the post-95 reg plug harnesses. Anyways, I have a 2000 Johnson that I just bought. There is a buzzer connected to the wiring harness and I jumped 12v to it and it works well. I grounded the tan wire at the block and no sound. I realized that in order for this to work the 6 pin square plug has to be connected to the system check tachometer in order for the buzzer to get a signal.

This is a small boat that has no tach. I am trying to find which wire I can jump the horn off of the system check plug to get my buzzer to work. The powerpack is in fact hooked to the temp swtich, so it will go into SLOW mode if overheated, but I would like to get the buzzer to work too. I traced all of the wiring back from the square plug and cannot find continuity to the tan temp wire at the engine. Any ideas?? Thanks!

 

[Joe Reeves]

I'm not familiar with the circuitry of the 2000 models but I doubt that has been any change so I"ll make a starting entry here.

There should be a built in black ground wire from the horn to a ground..... a purple wire attached to a slide on terminal carrying 12v ONLY when the key is in the RUN or START mode... and a TAN wire attached to the slide on terminal that is closest to that built in black wire which leads to the sensors at the engine and oil tank.

There should be no need to jump 12v to the horn... Do you have 12v at the purple wire at the horn when the key is in the ON position (engine NOT running)? If not, that accounts for why the horn doesn't sound when you ground the TAN wire.

 

[sutor623]

Thanks Joe. I havent checked for 12v at purple, but I think it is getting power. The issue is with this system, if the 6 pin "system check" plug isnt plugged up, the tan lead that goes to the warning horn isnt going anywhere but to a blank pin. If the system check harness isnt hooked to anything, it is IMPOSSIBLE for the buzzer to get grounded through the temp switch. EIther I need to hook the harness up to an appropriate tach, or I need to hook that tan wire into a wire that is continuous with the tan lead that hooks to the temp sender (which I cannot find via continuity testing.)

 

[daselbee]

You have two choices. You can buy a Systems Check Tach or you can buy the horn driver alarm module. Both have 8(?) pin sockets that accept the harness plug.

The tach and module are "smarter" than the old design, and require the engine to be running for the old "ground the tan wire" trick to work.
Also, the alarm only sounds for 10 seconds when a fault occurs, like overheat, and you are required to look at the tach to see which light is ON for the fault that occurred.

 

[sutor623]

Thanks Das, this is great input!!

I ended up tracing the harness back, and discovered that if you jump pin 6 to pin 8 on the "system check" harness, and ground out the tan wire to the block, the alarm sounds!! (I have the small alarm box that is hooked to a different harness on the wiring harness.) So basically I figured out what I was trying to do. Be cheap and not have to get the systems check module, and still have the alarm if the engine overheats.

The oil injection system has been bypassed, so I dont feel as having the system check to be of much value.

 

[daselbee]

I thought you wanted ALL your warning horn options working. You will be missing the vacuum switch.......

 

[Joe Reeves]

So basically I figured out what I was trying to do. Be cheap and not have to get the systems check module, and still have the alarm if the engine overheats.

I understand your line of thought and agree with it to a point (Saving a $), however... That's the beginning of what we in the trade refer to as "Patch Work" ad as time goes by, if that trend continues, it will interfere with troubleshooting other various electronic/electrical problems.

 

[sutor623]

I hear ya Joe. I'm pretty legitimate with what I do but want to keep this boat simple. I am just going to install a jumper in the harness and keep it clean.

Das, would the vacuum switch still activate if the vro has been disabled?

 

[daselbee]

Yes. It is not connected to VRO wiring at all.

 

[daselbee]

Examine the harness plug at the helm that has eight pin contacts. You will see the wire colors are mostly tan with some varying color stripe.
Of course it has grey, purple and black, but the majority are tan/stripe wires.
That plug connects to the Systems Check Tach or the horn driver module.

The grey wire supplies a tach pulse tot he Systems Check Tach obviously so that the RPM can be displayed, but the engine must be running
for the electronics to operate and indicate which alarm is active.

Tan is overheat
Tan/yellow is no oil as sensed by the VRO circuitry
Tan/blue is the horn activation line
Tan/black is the oil tank sender for low oil
Tan/orange is the vacuum switch which senses too much suction in the incoming fuel line.

Your factory service manual defines these lines very well.

The Systems Check Tach sorts out which line is actively indicating a fault and activates the tan/blue to sound the horn.

 

[daselbee]

You know, I just don't understand my memory these days. There is this option also:
http://www.ebay.com/itm/272282312140?ul_noapp=true

 

[sutor623]

Thanks man!!