rusty65

Hey guys,

Im trying to wire up a tachometer and oil pressure gauge in my 65 coupe, and they both need to be wired into a switched 12 volt power source so when the key is in ACC or ON position they receive power.

So im wondering, can I attach both of these wires to the same switched 12v source, and where can I find a switched 12v source in my 65 coupe thatll work?

TIA

Gun Jam

Yes tie both red (+12v) wires together and then run a single wire from the two wires to the fuse block under the dash on driver side. Find a fuse using a multi meter or test that gets 12v when the key is set to "on" I think the fuse labeled "ACC" would be a good choice.

they make clips that you can place under a round fuse and attach a spade connector to. You would use one of these you can get them from napa.

Use you DMM or test light and find the side of the fuse that has no power the key is on (remove the fuse and test from one side to a ground like a bolt if it lights up use the other side that way the fuse acts as a bridge and if your tach or gauge short out it will still burn the fuse like it should. If you use the hot side the fuse is out of the loop and wont burn but the wires will)

-Gun

rusty65

Thanks Gun,

Also, Im wiring in an electric fuel pump as well, and need the same sort of connection. Would it be too much to run all 3 wires to the same port? Im planning on having an on/off switch and a safety shutoff, just need a 12 volt switched source to send the power.

Gun Jam

probably not so long as the fuel pump is not rated for more amps than the acc fuse (or at least the wire you run to the fuse block must be less than the rated amp of the fuse for example it may use a low amp trigger wire that closes a solenoid allowing high current to flow though another set of wires that may run direct to the battery)

-Gun

rusty65

Not sure I follow on that last piece of advice, but im thinking that ill leave the acc fuse for the gauges to be safe. And for the fuel pump, I was thinking that perhaps the stator terminal on my alternator, or the I post (was it the I post?) on my starter solenoid could provide power to the fuel pump since they both get 12 volt power when the key is in the acc/start/on position as I recall. Would that work for the pump? Cause itd sure make my life easier...

And thanks again Gun

Gun Jam

how many wires go to the fuel pump just 2?

Im not sure if using the alt post would be any better than the fuse block. maybe worse.

-Gun

chris66dad

I made a relay operated auxiliary circuit on the 66 to handle my power problems for additional circuits I needed.
Info: http://chris66dad.tripod.com/id42.html

rusty65

Gun - Yeah, the fuel pump needs only a power and a ground. Im just worried about putting too much draw on the acc port that I blow the fuse, and lose my fuel pump while im cruising down the road. I could handle just losing my gauges...

Chriss66dad - Thanks for the link. If i buy one of those relays do i simply run one wire to the ignition switch (86), one to the starter relay (30), one to ground (85), and then one off to the pump (87)? (with a fuse in there for safety, as you suggest, of course)

The red and black lines for unswitched and switched, respectively, has me a bit confused. Is there something more in depth i need to do? Do I need to run wires in the place of those lines to those posts pictures or....?

All your guys' input is a huge help, thanks again!