splicing into instrument lights for the tach?

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DartorDemon

DartorDemon

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I made an attempt to install a tachometer on my 73 duster and ran into a problem. I couldn't find where to tap into the dash lights so my tachometer will light up. Is there a common spot that people use on these cars?
 
Te easiest is to find your wire that runs to your radio. It should have two connections, one for the radio light and one for the power to the radio. You other option is the actual fuse box.
 
rob_robinson87 said:
Te easiest is to find your wire that runs to your radio. It should have two connections, one for the radio light and one for the power to the radio. You other option is the actual fuse box.
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I thought so too, but the original owner got lazy/ran into my same headache and just spliced the two power wires(lights/power) with the 12v ignition source.
 
If you want to dim the tach light with the instrument cluster, tie into the inst, fuse in the fusebox. If it.s ok that it's lit all the time, find a 12 volt power source that is lit when the key is on.
 
toolmanmike said:
If you want to dim the tach light with the instrument cluster, tie into the inst, fuse in the fusebox. If it.s ok that it's lit all the time, find a 12 volt power source that is lit when the key is on.
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And the fuse box is the black box under the dash that uses the old style(clear fuses) right?


I think i'm gonna have to get a manual tomorrow morning.

I wouldnt mind the tach light being on all the time depending on how bright it is.
 
As Toolmanmike said.....undo the fuse box, and find the fuse for the dash lights. If you don't have a test light, turn the dash lights on and pull a fuse until they go out. Then just put a spade on from the back and run the wire to the tach.
 
I always use the "Ignition Fused" at the fuse box and let the light stay on all the time when car is on. I hate splicing into harnesses if I don't have too.
 
Another vote for the ash tray light.

Worked like a charm and dims with instrument panel lights.
 
I light up my tach and accessory gauges via the fuse box instrument fuse.
Lights come on/off and dim with the dash lights.

Connector on a wire, tiny short screw through the hole in the fuse holder on the top of the fuse box.
Ground to the dash.
No cutting, splicing, unplugging.

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Headlight switch is the easiest place find the wire that is hot went parking or headlights are on...mine is a 68 Dart but the wiring is probably the same...if you want to do the instrument lights look for two orange wires on the very end fuse and tie in there...matthon's post shows it..
 
You should be able to find the circuit in your fuse box by testing each fuse with a test light. Check each one while turning on your lights. If you can`t do that you can tie into the orange wire that feeds the radio. It should be accompanied by a red wire in the same harness.
 
Fuse boxes are marked with "inst lights" or something to that effect.
 
My tach is tapped in right at my headlight switch.

There is a ton of places you can tap in at....just depends on if you want the light on when the power comes on and off when off and thats it? or if you want it to dim with the rest of your lights when you want them too.
 
Your box is marked "one thru seven" and not by what the circuit feeds. Instrument lamps are usually at then end, so either one or seven.....Some fuse boxes even have a spade available...

This is getting to be too many chefs in the kitchen and how they cook a simple egg.......
 
redfastback said:
Your box is marked "one thru seven" and not by what the circuit feeds. Instrument lamps are usually at then end, so either one or seven.....Some fuse boxes even have a spade available...

This is getting to be too many chefs in the kitchen and how they cook a simple egg.......
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Well i wouldnt say too many cooks in the kitchen, it seems like there isnt that much uniformity in these vehicles.

So here is an update and a newer and hopefully even more simple problem of me putting a wire in the wrong place.

I did like everyone suggested and as it turns out, my fuse box is one that had the extra spade available. I was able to just plug into that part of the box, then i found a ground that was being used for the radio. And spliced into the radios ignition/on power wire.(rather the radio then the expensive harness.

For the tach wire, the instructions say to connect to the negative side of the ignition coil. Which i did, but i get no response from the tach with the engine running. I took a picture to show where i connected the wire.

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Its the green wire
 
It appears asthough you have the right color wire connected to the right post for tach feed .... ( green tach on negative post) (White is dashlights/12v source) (red needs to be connected to a 12v key on hot such as radio power wire or lighter power wire or any key on fuse you can find) (and black needs to be grounded out).

It LOOKS like you have it right so either you missed a step and didnt connect a wire OR connected it to the wrong spot OR your tach is faulty.
 
DusterDude72 said:
It appears asthough you have the right color wire connected to the right post for tach feed .... ( green tach on negative post) (White is dashlights/12v source) (red needs to be connected to a 12v key on hot such as radio power wire or lighter power wire or any key on fuse you can find) (and black needs to be grounded out).

It LOOKS like you have it right so either you missed a step and didnt connect a wire OR connected it to the wrong spot OR your tach is faulty.
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ok, in that case i wonder if that stupid splicer didnt connect my power key/on power wire correctly.
 
DartorDemon said:
ok, in that case i wonder if that stupid splicer didnt connect my power key/on power wire correctly.
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OHH JEEZ.....tell me you didn't use scotch lock connectors? LOL I hate them things.

If that's the case than you just might find that its not making a good connection.

Id run through and make sure all of your wire are making solid connection and make sure you have everything in connected to the correct locations for the correct wires and you should be good to go.
 
DusterDude72 said:
OHH JEEZ.....tell me you didn't use scotch lock connectors? LOL I hate them things.

If that's the case than you just might find that its not making a good connection.

Id run through and make sure all of your wire are making solid connection and make sure you have everything in connected to the correct locations for the correct wires and you should be good to go.
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I wish i could say i didnt use them, but i did :(

All of my wires have good connections, but that one is questionable. Atleast it should be an easy fix.
 
Well good luck to you on it! hope that fix's it for you....if not lets us know and we will all try to help you get it figured out
 
Thanks for the help everyone.


It was that damn scotch lock. This time i just clipped the stereo wire and then got a little creative with a coupler to splice my tach power wire with the stereo's ignition power wire. Started up the car and the tach works great. All thats left to do is go by the hardware store and pick up a hose clamp.
 
SWEET!

Thats why i don't use them dang things lol....don't know how many times I have had to rip apart wiring in vehicles that someone had done electrical work to and I found that scotch locks were everywhere lol.

I was figuring that was what your problem was.

Glad to hear you got it all working!
 
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