270 Sundeck - junction box for smart craft gauges

GoFastr

Cool Runnings
Jan 20, 2016
165
Cayman Islands
Boat Info
2003 Sea Ray 270 SunDeck MX 6.2L MPI w/Bravo III
Tow: 2012 Ford F150 Raptor SVT
Engines
Mercruiser MX 6.2L MPI w/Bravo III
I'm trying to troubleshoot my wandering needle smartcraft gauge issue.

A new SC1000 system display monitor did not fix the issue as from what I understand that acts as the brain to collect information from the PCM and distribute it to the gauges.

Anyone know where the 4 way j-box is that connects the engine harness to the helm gauges is on a 2003 270 SD?

I have looked behind the helm gauge panel, in the gunnel behind the starboard speaker by the steering and don't see it.

My Sea Ray dealer says to look by the engine but I don't seem to see it there either.
Thx.
 
Does anyone know where this J-Box is?

Do the 240, 270, 290 SD's maybe have similar electrical layouts?
 
Don't expect you have junction box, as no need for single engine.. or do you have more than one SC1000 gauge ?

Any pics of your present wiring behind the dash?
 
Don't expect you have junction box, as no need for single engine.. or do you have more than one SC1000 gauge ?

Any pics of your present wiring behind the dash?

Ok thanks. Yep, single engine and single SC1000 display unit feeding SC100 system link gauges. No wonder I can't find a junction box!

I guess that makes sense but I was thinking it wouldn't be just one super long cable all the way from the engine to the helm.

I'll just reseat the connection by the engine then.
 
Ok - resolution found.

So after reseating the connection by the engine and the one to the gauge they were all acting the same way.
I pulled out the manual and started reading through it and it had a section for troubleshooting at the back of it.

The only thing it mentioned that seemed similar to my issue was this:
Erratic readings on all gauges -
On dual engine applications using single CAN line one engine must
have the three wire harnesses disconnected.

Anyways I also saw something about doing a Master Reset so I tried that procedure and wah-lah all gauges are now working correctly again!

I ran the engine on muffs for a while to verify water temp and oil pressure and all seems fine again.
I'm no longer doing 42 mph sitting in my driveway on the trailer at a depth of 114 feet with RPM's around 5000!

Thanks all!

Also need to install my Garmin GPSMAP 840xs and connect up my NMEA gateway to display the gauge info onto the Garmin so I can do some baseline information recording before switching over to my new SS 4 blade Signature props!

Life is good when you have boat projects that work out well!
 


Yes I have one in my starter kit to use for the NMEA 2000 gateway install next. Have to figure out where and how to mount the Garmin 840xs as it is too big for the space I initially thought I could put it. Once installed I can use the gateway to display the egine data to it and also the stereo stuff too.

Thanks again.
 
Good info!
Whenever I have a funny electrical issue, it has often been traced back to a poor ground, which is a recurring problem in fiberglass boats. Glad that you found this one.
 

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