Aftermarket Tach Wiring - How?

[petieg383]

OK totally newbie question here. Where do I get the power/lighting from for a Sunpro Tach. Not used to Mopar fuseboxes (I was brought up GM, sorry guys). It's a 70 Roadrunner. All I see are the 6 or so places for glass fuses behind the wall in the glovebox.

And if at all possible, show me, not just tell me. Wiring is way over my head.

 

[bigmanjbmopar]

On the back of the fuse box there are spade type connectors built into it. Just find one that is not being used and make your connection there, make sure you add an inline fuse to it as well just to be safe.

 

[440+6]

I'm guessing you have three wires to hook up
1 power, this should go to the back side of the fuse panel, there are two rows of terminals one is always hot and the other is only hot with the ignition on, you want the one that's only hot with the key in the run position.
2 lights, you should be able to find an orange wire behind your ash tray with a three terminal female bullet connector, it should have one free for you to plug into this is your dash lights and will dim your tach light along with the dash.
3 tach feed, this goes to the negative terminal on your coil.

 

[ODZKing]

You'll probably want to use a "keyed" power source. Meaning the power will only go to it when the key is on.
I would suggest putting a Y type connecter on something like the radio. All though that may cause interferance and noise.
I'm not sure if 70 had the newer style fuse block or the old with no external connections. 70 service manual shows the newer.
If it is the newer like on my 73, there will be outlets at the bottom for accessories.
One should be constant and one keyed.
Ignore the circle in the pic. I am referring to the two at the bottom, one is labeled "Batt" and the other I forget at the moment. Batt is constant.

 

[petieg383]

It's not my car, but this is what I'm working with. It's the older style block.

http://assets.hemmings.com/story_image/293211-1000-0.jpg?rev=3

Thanks for all the responses guys. I really do appreciate the help!!

 

[ODZKing]

I would go the Y plug route if it were me. I hate messing with the back of the fuse box.
See that plug hanging down in the pic? If its a red wire it should be a keyed.
There is a spot. I like doing things neatly. Get another connector and make a Y type plug. Be sure to use a fuse to the tach.

 

[bigmanjbmopar]

Your welcome, that block is the same one as I posted the back should look the same.

It's not my car, but this is what I'm working with. It's the older style block.

http://assets.hemmings.com/story_image/293211-1000-0.jpg?rev=3

Thanks for all the responses guys. I really do appreciate the help!!

 

[nm9stheham]

Rookie or not.... did you read the instructions with the Sunpro? They are very clear. Green wire to the coil-, red wire to the power source, white wire to the dimmer/insrument light circuit, and black wire to ground. I would use the instrument lights fused line to feed the red wire (that circuit typically has nothing critical on it), and increase the fuse rating by 1 amp. Don't connect it direct to the battery as noted above.

 

[petieg383]

Rookie or not.... did you read the instructions with the Sunpro? They are very clear. Green wire to the coil-, red wire to the power source, white wire to the dimmer/insrument light circuit, and black wire to ground. I would use the instrument lights fused line to feed the red wire (that circuit typically has nothing critical on it), and increase the fuse rating by 1 amp. Don't connect it direct to the battery as noted above.

Yep I read them. It's more I just didn't know where to find the ports for the spade type terminals. Never occurred to me it would be on the back like that. What genius thought that up? ;)

 

[bigmanjbmopar]

That would be me, I'm a "Super Genius"

 

[soundhd]

First question is do you have the Rally Dash? If so there is probably already the power and tach connections behind where the stock Tic-Toc-Tac goes........check your wiring diagram in your Shop Manual.

- - - Updated - - -

First time I have seen the rear of a B Body fuse panel.......looks like an "overload" waiting to happen.....pretty "scarey"........LOL

On the back of the fuse box there are spade type connectors built into it. Just find one that is not being used and make your connection there, make sure you add an inline fuse to it as well just to be safe.

 

[Dragon Slayer]

The other source for 12V is the PCB on the back of the rally dash. In my case, my 70RR did not come with tach, but had an E body 8K tach installed in the dash. I soldered a red wire to the 12V source on the PCB and routed a short wire with a fuse holder to the tach. If I have to pull the dash, I only have to detach the tach signal wire, and it comes out with the dash. G