wiring guages to ignition switch !?!

[chesiebaydecoys]

I added some new guages and accessories to my CC setup (fuel guage, hours meter, sirius radio) and they all have instructions to wire the lead to the ignition switch. I understand that i can 'daisy chain' the instruments via the "I" terminal on the back of the instruments so here's my question:

Q1. How to i actually wire a 'lead' from the ignition switch to the guage?

For example.. I had my local marina do the final connections on my new Tahatsu OB motor which included a new factory Tahatsu Tach, trim guage, controls but they all appear to be factory 'hardwired' and all connected via factory prefab wire harnesses. I looked up the color code for 'ingnition wire' and it's supposed to be 'PURPLE' however there is no 'PURPLE' wire in my harness coming out of the control box / key switch. Also, both the tach and trim guages appear to be factory 'hardwired' so there are not really any 'marked' terminals on the back of these guages to daisy chain off of.

Q2. Do i really have to wire the JBL Sirius CD/Radio to the ignition switch? or can I just run it to a rocker switch on my switch panel. I will still run the yellow constant to the battery terminal. Does it really matter if the lead doesn't go to the ignition switch?

Thanks in advance to everyone for their time and response..

Doll Fin
'73 Starcraft Mariner
Restored 2006

 

[drewpster]

Re: wiring guages to ignition switch !?!

No you do not have to run your radio power to the ignition switch. It is ok to run it to a separate rocker. Just be sure to protect the circuit with a fuse. Just remember to turn it off when the boat is at home. Also remember you need a fuse on the yellow wire as well.
Keep in mind that the yellow memory wire for your stereo draws a small amount of power all the time. If you are like the rest of us, your boat will stay at home more often than running down the lake. That yellow memory wire can run your batteries down. It is better to turn it off and lose the memory unless you keep your boat on a good charger.
Unlike our cars, that run almost every day, our boats tend to sit more. The batteries need to be disconnected or switched off, and keep them charged.

 

[Silvertip]

Re: wiring guages to ignition switch !?!

While I'm not familiar with Tohatsu, every other engine manufacturer I've dealt with has had a pigtail in the wire harness at the helm that has 12V on it when the ignition switch is on. That pigtail connection is for the express purpose of applying power to accessories. If you simply don't have that pigtail or if there really isn't one there, check the back of the ignition switch. There shoud be an "A" (accessory) terminal on the switch. Whatever color the wire is that's connected to that terminal is the wire you can tap into (via fuse or breaker) for any accessory you wish to add. You will then be assured that when the ignition is off, accessories are off. That said, you generally want to listen to a stereo system or VHF without the need for the ignition being on. This is especially important on four stroke motors. So you should have a MASTER switch that you wire those accessories to. This allows the ignition be turned off yet still allow operation of accessories. The MASTER switch kills those accessories not powered through the ignition switch.