replacing RPM gauge

My boat is in the shop right now and apparently needs a new tachometer. Because this is peak season for boat shops, and as a result they are charging $100/ hour, I said to order the part and I would connect the wires. Without knowing what I just got myself into I have been contemplating whether I should just pay extra and have them do it, or if it will be easy enough for me to get it done.

In the past I have installed many car stereos so I am thinking that it just means I have to connect red-red, black-black, etc.

thoughts??

Re: replacing RPM gauge

Since there is a tach installed already, note the color of the wires and terminals they connect to. Disconnect them, pull the old tach and install the new one. You do realize, if you buy the tach and then screw it up, the dealer will very likely say "nice to know ya!". Electronic parts are rarely returnable. This is really a simple job, but just in case you are really electrically challenged, you might want to rethink things.

Re: replacing RPM gauge

Thanks Silvertip.

They have already disconnected the old tach so I don't know how the wires were hooked up. I asked them to just give me the new tach and I would figure it out. How hard could it be?

There is no switch involved so wouldn't the colors on the back of the tach match what is behind the dash on my boat??

Set me straight if I am over simplifying things

Re: replacing RPM gauge

No colors on the back of the tach. It has an "I" terminal (+12V when the key is on), an "S" terminal (send wire from the ignition), a "G" terminal (ground), and an "L" terminal (back light). If the wires on the old tach have already been disconnected, how do you know which one is which? If you have, and know how to operate a multi-tester it is not difficult to figure this out. It's usually the "S" terminal that gives people fits. But why not identify the other three -- then its a simple process of elimination.

Another technique (no meter required) would be to look at any of the other gauges. A gas gauge for example has an "I" terminal. Note the color of that wire. The same color tach wire then goes to the "I" terminal on the tach. The gas gauge also has a "G" terminal. Note that color. The same color wire for the tach goes on the tach "G" terminal. Every gauge in the dash has an "L" light terminal. Yup -- it works the same way for the tach. But now you are left with the "S" terminal. I'll just bet you have only one wire left and there's a pretty good chance it goes to the "S" terminal.

Re: replacing RPM gauge

Thank you.

You have given me enough info to at least make an educated decision as to whether or not I can do it on my own.