Wiring Woes

[CapeFearDiveGal]

Hi all,<br /><br />I'm trying to finish up my 1972 GW project boat to get her in the water for the first time(for me anyway). <br /><br />Anyhow, I'm trying to wire up the lights, bilge pump, and blower. I found a 8-10 gauge red wire running from the rear of the boat up to a post on the back of the water temp gauge. I'm pretty sure this is my hot wire from the battery. Then a jumper goes from there to a fuse block to provide power for all the accessories. No problem, I'm thinking, finding the hot wire is half the battle. And, I've got a nice fuse panel to run all my accessories off of. <br /><br />So, then I try and find the ground. The only other wire running back to the back of the boat from the helm is an orange wire of about the same 8-10 gauge. This has to be it, I'm thinking. I test connectivity, and sure enough, it connects up to the negative battery cable. <br /><br />But, here's the problem. The orange wire also goes to another post on the same water gauge. And somehow the 2 are connected across the gauge. This means if I hook up the battery I'm going to have a major short, right? <br /><br />Could the gauge be faulty, letting it short out? Or is this just some hokey wiring to begin with? I'm no electrician, but running the pos and neg bus wires from the battery to some gauge on the dash doesn't seem to be the best way to wire a boat to me. <br /><br />I'm thinking of isolating the 2 wires to blocks and running power and ground from there; then perhaps trying to wire up the water gauge or just getting another gauge. Any ideas? Thanks in advance!!

 

[cp]

Re: Wiring Woes

Suggest you contact Grady; they're pretty helpful. Maybe they'll even send you a wiring diagram for the boat. Good luck.

 

[Ralph 123]

Re: Wiring Woes

Here is a typical temp gauage schematic:<br /><br /> http://www.tflx.com/PDF/IE8822.pdf

 

[datawire]

Re: Wiring Woes

Are those 2 wires the only ones on the gauge? If the gauge is illuminated... it would need a negative feed. Could be they just used that point as a handy place to tap off of.

 

[Ralph 123]

Re: Wiring Woes

You typically have an "I" terminal which goes to the "IGN" terminal of the ignition switch. A "G" terminal that goes to a ground point. An "S" that goes to the sender. If they are illuminated you have an "L" terminal that goes to a switch to turn the lights on and off.

 

[swist]

Re: Wiring Woes

How did you determine there is a "short" across the temp gauge? If the previous post is right and there's a dash light in there, a cold bulb has very low resistance (and unless you have an accurate ohmmeter on its lowest scale, it might be difficult to tell the difference between a short and a normal condition. Don't forget ohm's law (resistance = voltage divided by current). A device with static draw of 1 amp at 12 volts will only measure 12 ohms! And 1 amp isn't a lot in marine applications. Same deal with motors (bilge pumps etc). At rest their resistance is going to look pretty close to zero. Make sure the line is fused for the wire size (30A fuse for 10 gauge wire) and if something really is shorted, you'll blow the fuse long before you cook anything.<br /><br />[And a private rant here - can't the marine industry agree on a color code for boat wiring? Or I suspect they have but not everyone follows it. Would make tracing wiring problems a lot easier. I have every color of the rainbow in my boat's harnesses and none of them make any sense].

 

[Ralph 123]

Re: Wiring Woes

Here is a good way to test your gauges:<br /><br /> http://www.tflx.com/pdf/GAUWORK.pdf <br /><br />And yes there is a color code and all of the boats I've worked on have used the code. Here is the color key:<br /><br /> http://www.ancorproducts.com/Technical_information/Marine_Color_Code.html