Electrical Holley digital dash and no battery charging issue

bklemm

New Member
Jul 27, 2022
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Lynnwood, WA
I have an 89LX foxbody I have replaced the original dash with a holley 12.3" digital dash and the alternator will not charge the battery. I have looked at a couple forums and have found that the original dash is used to excite the alternator. In the thread I read, if a 1/2 watt 470-520 ohm resistor is placed between the wires from the original dash of number 2 and 14, this will excite the alternator to charge the battery. Has anyone installed a holley digital dash and figured this out? I will attach the file with the original wiring of the instrument cluster as well to try and help with what I am talking about.
I did order a self exciting regulator from PA performance that will eliminate the issue I believe (from a 3 wire to a 2 wire regulator) but I still want to figure it out because I don't like unsolved issues with the car.

Any thoughts and help is much appreciated.
 

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The battery light in the dash (incandescent light bulb) is in parallel with a resistor that is attached to the back of the instrument cluster. The function of the resistor is to keep the alternator charging if the bulb burns out i.e. no longer provides resistance.

Some simply wire a dash light into the circuit and leave it behind the dash so it will work. If you do this make sure to mount it so that if it does come on (ignition on and motor not running) that it doesn’t melt something you don’t want it to.

I had this problem but it was installing all the Autometer gauges in the Thunderbird because I used and LED for the battery warning indicator. I ended up stealing the factory resistor off the back of the factory instrument cluster, wired it in parallel, and problem solved.
 
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The battery light in the dash (incandescent light bulb) is in parallel with a resistor that is attached to the back of the instrument cluster. The function of the resistor is to keep the alternator charging if the bulb burns out i.e. no longer provides resistance.

Some simply wire a dash light into the circuit and leave it behind the dash so it will work. If you do this make sure to mount it so that if it does come on (ignition on and motor not running) that it doesn’t melt something you don’t want it to.

I had this problem but it was installing all the Autometer gauges in the Thunderbird because I used and LED for the battery warning indicator. I ended up stealing the factory resistor off the back of the factory instrument cluster, wired it in parallel, and problem solved.
Thank you for the reply. I will take a look at the cluster and wiring this weekend.
 
Im running the Holley pro dash as well. I made a jumper harness with resistor between pins 2 and 14. Worked fine for a few years until recently. I think the resistor was going bad or overheating. I was getting an intermittent issue where the alternator would stop working and car ran on battery alone. I just rewired it from a straight 12v ignition tap to the 12v wire on the 3 prong harness. So far so good.