I am looking at swapping my dash cluster out for a custom job. I would like install all my gauges; tach, oil, temp, volt, tranny temp, and a new speedometer in place of whats there now. Also, I would like to use a few LEDs for the turn signal and high beam. Now my question is, how much of a PITA would it be to wire all those gauges in sequence so that I have light on all when I turn the lights on? What are some things to look for, or to make this an easier job.
I am just trying to get a feel for this task as I will just be helping a friend of mine do the electrical if I decide to go through with it.
Thanks for any advice you all have.

 

Wiring the illumination would not be the hard part. Running and hooking up all the sending units will be the hard part. And the LED's may make the turnsignal flasher not work. It usually messes up the flasher when LED taillights are installed, but I do not know if LED dash indicators would mess it up or not.

 

Thanks Dave. With what you said about LEDs cancelling the flashers out, would regular bulbs work for me better? I was just figuring LEDs would be kinda cool, but they arent a must.
Also, which sending units are you all speaking of? The one for the gas tank hasnt worked in years! so I figure get a new one for that and I have a brand new, still in the box, sending unit in the garage just waiting to be put in this spring.

 

Regular bulbs will work for the turn indicators. That's what the factory used. The flasher works on bulb load, and the LED's don't draw much current, so that's where the problems come in. They have load resistors you can install to overcome this, but it's one more complication.

I am assuming you are going to make a new panel out of wood or aluminum, etc., and then buy aftermarket gauges and wire them all up. If this is the case, you are going to have to get a diagram, and spec out all the different color wires you have now, and what they do.

For instance, the blue/red is the dash illumination wire, so you will need this wire to hook all the gauge illumination up.

You should have a gauge regulator mounted in the original dash panel. You will not need the regulator, but you will need the key on power source that feeds it to feed power to all the new gauges.

You need to find all the different color wires for the sending units, find out where they go, and hook them to the correct gauge. You will not be able to use the original ammeter gauge wiring, especially if you use a voltmeter instead(I recommend this). You could use the same wire that powers the rest of the gauges for the new voltmeter.

You need to check the new gauges, and see if their sending units are compatible with the Ford sending units. Most of the time, they are not.

 

Thanks Dave, I will get a schematic for the dash. As for what its going in, I havent decided if I want to go with wood or say hell with it and do with aluminum. The polished diamond plate would look nice though.lol
As for the sending unit and an aftermarket gauge, is it an ohm thing, or is there a little more to it? I havent bought the gauge yet, but I can always match it up with one that conforms, right?

 

I did this last year and you're on track for what to do. With the wiring diagram in hand you'll know what wires to run to. The lights in most gauges are enough and easy to hook up. For the fuel senders just check on what your stock gauge is (resistance) and match it, the speedo will require a new cable if you're putting an AutoMeter one in a '78 (AutoMeter list a supplier on there site and he's good to deal with). Get LED's with the load resistors, you usually see them at Car Shows or any light supply site. Mine work great for the blinkers and high beam.
The only change is that I may fully gut the dash pod and use metal so that I can sink the monster tach in with the rest.
If you search the site you'll find lot's of approaches, using the stock dash, custom plates, whole new dashes. Let us know how it goes.

 

Yes, you are correct, it's the ohms, hot or cold, full or empty, etc. Usually they will come with their own sending units for the oil pressure and water temp, but the rub comes in with the fuel tank. Try to get one that is compatible with your year Ford fuel tank sending unit.

 

Hey 77460, I love the dash! That is even better than what I was thinking. I dont mind if a couple of the gauges are mounted seperate, but if I can get all of them in there, even better, but you did a great job and I can handle doing that with mine. Thanks to you and Dave both for the help!

Mike

 

78stepside429,

Good luck and show us how you made out. If you use an AutoMeter speedo then you'll need a new cable and www.speedometersolutions.com is the place. Roger will fix you up, you just need to give him the length you need and the ends required, a HD steel case cable was about $60. To get the ohm range for your fuel sender you can check with a parts place (if they actually know how to look it up) for your tank setup. A dremel is the handiest tool you can have in your arsenal.

John.

 

Dave,
I know it sounds kind of off the wall, but is there any way to check the sending unit for the ohms? the new one I have is from LMC and Im not sure if its going to be the same as the original. I wouldnt wanna screw this up before I even get it started. Thanks again.

Mike

 

If you have the new one laying there, and a voltmeter with an ohms scale, it will be very easy.

Put the meter on rx1 scale, and touch the meter leads together. Make sure it reads zero. Some meters have an adjustment wheel for this.

Then put one meter lead on the stud where the sending wire hooks, and the other meter lead on a metal part of the sending unit. While holding the meter leads, move the float arm up and down. You should see the meter readout move up and down. Note the reading with the arm down(empty), and the arm up (full). Off the top of my head, I am thinking your unit is 0-90 ohms. Don't panic if you get 5 or 10 ohms and 80 to somewhere around 100 ohms. It just has to be in the ballpark.