Moderated Discussion Areas
  ContinuousWave: Small Boat Electrical
  GPS/FF install on a 170 Montauk

Post New Topic  Post Reply
search | FAQ | profile | register | author help

Author Topic:   GPS/FF install on a 170 Montauk
bigjohn1 posted 10-16-2006 09:13 AM ET (US)   Profile for bigjohn1   Send Email to bigjohn1  
I am re-wiring the GPS/Fishfinder unit in my 170 Montauk. When I originally installed the unit, I committed the cardinal sin of using standard automotive wire to interface those tiny 22 or 24AWG NMEA wires directly to the battery via an inline fuse. It has worked fine to date and this was to be a temporary install till I got around to doing it right.

I realize I should be wiring this unit to the boat's accesory switch and I will need to add an inline fuse of 2amps (per my Navman manual). I am at a bit of a loss as to the professional way of interfacing those very small hot and ground wires (22/24AWG?) from the NMEA cable bundle to the back of the ACC switch. I will use all the quality Ancor marine connectors in this job. I need to fashion two short 18AWG cable lengths (hot and ground) to interface between the NMEA cables and the back of the ACC switch. If this were a land-based peice of equipment, I would simply solder but after reading this forum for a few years, the consensus seems to be that soldering is "out" and Ancor butt connectors are "in". OK, I am now a believer but how does once interface a very small cable with a much larger one when using butt connectors? Am I missing something in the Ancor products catalogue?

I want to do this right on this go-around and never have to mess with it again.

Chuck Tribolet posted 10-16-2006 10:08 AM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
Soldering is fine. Cover it with the Ancor hot-melt-glue-lined
heat shrink tubing with a good 3/4" of overlap onto the
insulation. That will provide the strain relief required to
keep the wire from breaking at the end of the solder.

Be sure not to forget to slide the tubing on BEFORE soldering
(been there, forgot that) and to slide the tubing well away
from the solder joint so the soldering doesn't shink it
(been there, forgot that).


bigjohn1 posted 10-17-2006 09:16 PM ET (US)     Profile for bigjohn1  Send Email to bigjohn1     
Thanks for your reply Chuck. For the life of me though, I cannot understand why in the heck the maufacturers make those cables so friggin small - they are perhaps 1/2 the diameter of a 20 or 22AWG cable.
Chuck Tribolet posted 10-17-2006 10:19 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
I agree with you Big John. Esp. when the ABYC codes call
for nothing smaller than (IIRC) 18 ga.


norsman posted 10-23-2006 05:20 PM ET (US)     Profile for norsman  Send Email to norsman     
I ran the accessory lead to a terminal block so I could tapp off of it for all the accessories. This is inside my console. If you do it this way, you can then put a spade terminal on with a AWG close to that of the NMEA wires you are trying to join. Then the butt splice crimp will work better.

Also, don't forget to waterproof and shrinktube!


contender posted 10-23-2006 10:52 PM ET (US)     Profile for contender  Send Email to contender     
I like doing things once...I pull the plastic off the crimp, crimp the wire, solder the joint, heat shrink the area, and add some type of sealer, The wires are getting smaller because of the cost of copper... save a buck, I agree with norsman I also set up my own wires on a terminal block.. good luck
Chuck Tribolet posted 10-23-2006 11:19 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
Use a ring terminal, not a spade terminal.


bigjohn1 posted 11-14-2006 09:03 PM ET (US)     Profile for bigjohn1  Send Email to bigjohn1     
OK, one final question for the experts. I want to wire my unit so it automatically powers up when the key switch is turned. This is the only wiring option to ensure the engine hours counter function will work as well as the fuel sensor. The below link is the wiring instructions for my unit. I want to wire for "auto power" (the second or middle image on the page). With the 170 Montauk, how is this accomplished given that the ignition switch is sealed and there is no battery switch?

I know my ground is to the battery but I tried connecting the red and yellow wires to the back of the factory "ACC" switch but the unit would not power up. The same happened when going to the factory "Stereo" switch (and yes, I turned the switched on)

I realize norsman's idea of adding a terminal block is very smart and probably the best way but that will have to wait for another day.

Here are my knowns: The unit is operating properly and no fuses are blown. I am using 2 amp inline fuses on both red and yellow wires.

1-page wiring diagram:

Wiring is not my cup of tea as evidenced by the fact that I used the unit wired straight to the battery for over a year. I realize this is not the best way to go and am trying to make it right - thanks for the help.

Chuck Tribolet posted 11-14-2006 11:30 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
Even if you wire it to the ignition switch, you will still
have to remember to turn on the GPS/FF.

With the switch on, you shouldn't be having trouble
getting power at the acc and stereo switches. I'd jury rig
something straight to the battery (jumper cables will do,
but be careful not to short them) just to be sure the GPS/FF
was still working. Actually, I'd hook it to 12V bench power
supply, but you probably don't have one of those. ;-)


bigjohn1 posted 11-15-2006 12:53 AM ET (US)     Profile for bigjohn1  Send Email to bigjohn1     
Chuck, One of the knowns is the unit IS operating properly. I confirmed this first by straight wiring to battery - its works fine when it gets power. The wiring setup in the attached diagram is for auto-power and the unit's on/off button has no effect on the unit once its properly wired, it is powered on and off simply by a turn of the ignition key. When you try and turn off the unit by its power switch, a screen will say, "Cannot turn off power when in auto mode".
Chuck Tribolet posted 11-15-2006 12:10 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
The ignition switch may be sealed, but there are other places
to pick up 12V with the ignition on. 170 Montauk so it's
got Merc instruments, right? GPS black to ground. GPS yellow
to the purple wire running behind the instruments. GPS red to
full time 12V (pick it up from the line side of the ACC
switch, or trace that wire back towards the battery and you
may find a terminal block.).


bigjohn1 posted 11-15-2006 07:56 PM ET (US)     Profile for bigjohn1  Send Email to bigjohn1     
Thanks Chuck, that makes it a bit more clear. I'll try those routes tonight.

Post New Topic  Post Reply
Hop to:

Contact Us | RETURN to ContinuousWave Top Page

Powered by: Ultimate Bulletin Board, Freeware Version 2000
Purchase our Licensed Version- which adds many more features!
© Infopop Corporation (formerly Madrona Park, Inc.), 1998 - 2000.