White Dash Lights wire not powered? - FFCars.com : Factory Five Racing Discussion Forum

 
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post #1 of 15 (permalink) Old 05-26-2017, 12:34 AM Thread Starter
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White Dash Lights wire not powered?

We've been going through the gauges one at a time troubleshooting them and we noticed that the gauge lighting (face and needles) aren't working. After checking all of the wires we moved the power wire from the white "Dash Lights" wires to the "Radio Power" wire (just to make it easier to test) and suddenly them work! Confirmed with both the lighting faces and the needles. Plug them back into any of the Dash Lights wires and they don't work anymore. The ground always stays the same. What gives?

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post #2 of 15 (permalink) Old 05-26-2017, 01:09 AM
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Is it possible that the dash light circuit only has power when the car is running?


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post #3 of 15 (permalink) Old 05-26-2017, 01:15 AM Thread Starter
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Originally Posted by Dan Babb View Post
Is it possible that the dash light circuit only has power when the car is running?

Tried that too - run and started were the same. Nothing through the Dash Lights wire.
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post #4 of 15 (permalink) Old 05-26-2017, 01:17 AM
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I had a similar issue last year when I first hooked up my dash lights. Turned out I had a bent pin in for the headlight switch where it plugs into the harness. I bent the pin back and it started to work for me. Since the dash lights works off this switch if the connections are not perfect you may have a similar issue as I did.

Good Luck Kevin
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post #5 of 15 (permalink) Old 05-26-2017, 01:19 AM Thread Starter
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I had a similar issue last year when I first hooked up my dash lights. Turned out I had a bend in for the headlight switch. Since the dash lights works off this switch if the connections are not perfect you may have a similar issue as I did.



Good Luck Kevin


Does that mean head only come on when the headlights are on? If so, I probably need to turn them on huh?
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post #6 of 15 (permalink) Old 05-26-2017, 02:00 AM Thread Starter
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Does that mean head only come on when the headlights are on? If so, I probably need to turn them on huh?


Headlight switch didn't make a difference. I assume we don't need the actual headlines guys connected for this to work?
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post #7 of 15 (permalink) Old 05-26-2017, 03:34 AM
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Dash lights are switched on by the headlight switch (first or second position) and do not require the ignition to be on. Same as your DD. Doesn't make any difference whether other lights (headlights, running lights) are attached.

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post #8 of 15 (permalink) Old 05-26-2017, 09:08 AM
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Just a thought, is the light switch rotated to the dimmest position so the lights are off? Try rotating the stem on the light switch.

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post #9 of 15 (permalink) Old 05-26-2017, 01:41 PM
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Dash light run through the dimmer on your headlight switch. They could run off the parking light post, but then you don't have dimming


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post #10 of 15 (permalink) Old 05-26-2017, 02:14 PM
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Quote:
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Dash light run through the dimmer on your headlight switch. They could run off the parking light post, but then you don't have dimming.
You don't want/need the gauge dimming function through the headlight switch with the Speedhut gauges. The needles are always lit red (well, except the clock, but that's another story) and the backlighting goes through the Speedhut inverter with its own dimming knob.


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post #11 of 15 (permalink) Old 05-26-2017, 07:43 PM
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Quote:
Originally Posted by edwardb View Post
You don't want/need the gauge dimming function through the headlight switch with the Speedhut gauges. The needles are always lit red (well, except the clock, but that's another story) and the backlighting goes through the Speedhut inverter with its own dimming knob.
Ok, learned something today. Wasn't familiar with the Speedhut gauges and their inverter with dimming. So the question is what about the Speedhut dimmer? Is it turned all the way down?

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post #12 of 15 (permalink) Old 05-26-2017, 10:32 PM
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Ok, learned something today. Wasn't familiar with the Speedhut gauges and their inverter with dimming. So the question is what about the Speedhut dimmer? Is it turned all the way down?
That depends, the dimmer is a small variable resistor that allows you to select how much voltage will be applied to your lighting circuits in the gauges. First, determine if voltage is getting to the Speedhut dimmer when you turn on the ignition. This all depends on how what you wired to as the voltage source for the lighting. If you don't have voltage to the dimmer, work back to where you wired to for the source. If you don't have a voltage/ohmmeter, you can get a cheap one at Harbor Freight or similar source. On my car, I identified all the 12V sources and when they are hot, that is accessory position, ignition, start, run etc. Knowing when these sources of 12V are hot determines what they should and can be used for. Good luck, once you can trace back to an active source, characterize it so that you know when it is on and go from there.

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post #13 of 15 (permalink) Old 05-27-2017, 07:57 PM
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Ok, familiarized myself with the Speedhut gauges. I see from the wiring instructions that the inverter/dimmer is for the backlighting only and the pointer is not dimmed. He said the gauges worked (backlighting and pointer) when connected to the radio power, but not when connected to the white dash light wire. In my RF harness the white dash light wire goes to pin 2 of my light switch and does go through the dimmer portion of the switch to pin 5 which is fed from a 15 amp fuse. So, pull the switch out 1 or 2 positions, make sure it is not dimmed, and check the fuse.

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post #14 of 15 (permalink) Old 05-27-2017, 10:25 PM
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Quote:
Originally Posted by Otto Halstead View Post
Ok, familiarized myself with the Speedhut gauges. I see from the wiring instructions that the inverter/dimmer is for the backlighting only and the pointer is not dimmed. He said the gauges worked (backlighting and pointer) when connected to the radio power, but not when connected to the white dash light wire. In my RF harness the white dash light wire goes to pin 2 of my light switch and does go through the dimmer portion of the switch to pin 5 which is fed from a 15 amp fuse. So, pull the switch out 1 or 2 positions, make sure it is not dimmed, and check the fuse. HTH
Your summary of the Speedhut gauge lighting function is correct. Similar to what I said in post #10. I suspect you're right that the headlight knob is likely fully twisted clockwise putting the gauge light circuit in the off position. If you twist it all the way counter-clockwise, the gauge dimming circuit is in the full on position and the white wire should have full voltage. Note that at the counter-clockwise position, there's a detent and it can be twisted slightly further. That turns on the courtesy light circuit. I personally use that to light the footwells. But it could be used for something else.

I would not use the radio wire for the gauge lighting. It's an ignition circuit, meaning the gauges would only be lit when the key is on. Plus they would be lit all the time. Neither would be desireable. Using the correct white gauge lighting wire, the gauge lighting is always switched on with the headlight switch whether the key is on or off. Just how you want it.

I've wired the two builds where I used Speedhut gauges with the white RF gauge light wire on the Speedhut gauge lighting circuit. Neither the backlighting through the DC-to-AC inverter or the LED lit pointers seem particularly sensitive to voltage. As long as the dimmer knob on the headlight switch isn't in the fully clockwise position (e.g. off) as explained previously, there's enough voltage to light everything. I just now checked #8674 and that's exactly how it works. The gauge lighting is at full intensity except when the knob is turned fully clockwise, then the lighting simply switches off. Only the Speedhut dimmer knob changes the gauge backlighting. Since the headlight knob doesn't dim the gauges, I just leave it in the counter-clockwise position. Then use it only to click the courtesy lights on and off. As long as it's kept rotated in that direction, the gauge lighting will always work.

Hope that all makes sense. In the end, it's pretty simple. But agree it can be confusing until you get it sorted out.

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Last edited by edwardb; 05-27-2017 at 10:35 PM.
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post #15 of 15 (permalink) Old 05-27-2017, 10:34 PM
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Simply splice the the gauge light feed wires in parallel with the park/tail feed from the headlight switch. The switch dimmer position will be moot and when you pull the headlight switch on you'll have power to the gauge lighting same as when you introduce it via the radio memory wire.



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