Tach Illumination lights do not work

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Old Jun 28, 2012 | 03:40 AM
  #1  
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Talking Tach Illumination lights do not work

Ever since i got the car in June of 2010 the lights in the tach do not work. I pulled the tach out last night and i checked all wiring going to the tach with a test light that i have power going to the unit. I changed the bulbs clean the the areas that needed for concact and lights still do not work. Any suggestions???
Old Jun 28, 2012 | 03:53 AM
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Do you have power coming from the plug on the harness?

- Eric
Old Jun 28, 2012 | 03:56 AM
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Yes there is power coming from both wires going to the tach, orange one is for the clock and gray one for the lights.
Old Jun 28, 2012 | 05:14 AM
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Originally Posted by m455sx
Yes there is power coming from both wires going to the tach, orange one is for the clock and gray one for the lights.
Is the ground wire attached?

Did you bench test the whole unit when it was out?

If so did you bench test each bulb to make sure they worked?
Old Jun 28, 2012 | 05:19 AM
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Ground wire? As per manual no ground wire listed or shown, I have tested bulbs with multi-meter. I have a hard time with electrical so please be patient!!! It seems to be self grounding. Would the clock and tach work with no ground? Please explain the best way to bench test.
Old Jun 28, 2012 | 05:29 AM
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Originally Posted by m455sx
Ground wire? As per manual no ground wire listed or shown, I have tested bulbs with multi-meter. I have a hard time with electrical so please be patient!!! It seems to be self grounding. Would the clock and tach work with no ground? Please explain the best way to bench test.
On a 68-69 there's a ground wire that that grounds the body of the tach. It's a jumper wire from the speedo. I don't know if your's has that but in order for the lights (or the clock) to work the unit has to be grounded.

With the tach out of the car simply run a wire from the negative on your battery to the steel body of the tach and another wire from the positive terminal to the light feed and see if the lights work. If they don't light up then remove the bulbs and test them individually.

Last edited by allyolds68; Jun 28, 2012 at 05:34 AM.
Old Jun 28, 2012 | 07:18 AM
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I will bench test the unit tonight. I have already tested the bulbsand they are fine.
Old Jun 28, 2012 | 05:45 PM
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bench tested and not working. Cleaned contacts with Emory cloth and the lights work very well.
Old Jun 28, 2012 | 06:58 PM
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Alright, we need some photographs here.

If I am not mistaken, there is essentially nothing to the wiring on these units - a few short wires and that's it.

You've just got to test each part of the circuit until you find the place where the electricity stops.

- Eric
Old Jun 29, 2012 | 02:19 PM
  #10  
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Hey man a day late and a dollar short!! Gauge pod was installed asap once light bulbs were working. Maybe pictures next time.
Old Jun 29, 2012 | 02:41 PM
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Originally Posted by MDchanic
Alright, we need some photographs here.
If I am not mistaken, there is essentially nothing to the wiring on these units - a few short wires and that's it.
You've just got to test each part of the circuit until you find the place where the electricity stops.
Eric, you'd be right on that. The 70-72 rallye pac is simple wiring. Most of the ground issues are from the metal strips fixed to the dash that the pod bolts go through to get
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