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Do the new electronic gauges use an led to backlight the gauge and needle. I have the headlight switch and the rheostat on the switch does not dim the guages. Read that you cannot dim the leds, could that be my problem or something else?



Rob
 

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Same here, I guess the ilumination is done with led bulbs and cannot be dimmed...
 

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FFCobra Craftsman
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My complete kit came with Autometer electronic gauges with incandescent lights. They work fine with the FFR supplied headlight switch dimmer. They may have changed the gauges or lights since last year though. One way to tell if you have LEDs is to swap the wires and see if they work. Incandescents are not polarity (+/-)sensitive.

Randy
 

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If the illumination is LED, you need to take a different approach to dim them properly - most off-the-shelf options use PWM (pulse width modulation) to quickly turn the LEDs on&off (faster than your eye will detect hopefully) - the duty cycle of on vs off will determine the brightness.

I'm too cheap to drop the $50 that Autometer wanted for their dimmer, so on my list of stuff is a simple DIY PWM circuit - would be 3 wires to a little box (illumination line in, ground, line out to the LEDs that need dimming) with a little knob to control brightness.

If there's interest, I'll write up the build so it is easier to copy.
thoughts?
timm
 

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I'd be interested, however I;m not sure if I have led, I'm approaching this part shortly
 

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You could also call Speedhut and see if they have a solution. They are the ones manufacturing these.

Chris

TD I would be interested in seeing the circuit as well.
 

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Kriss Motors
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Dimming FFR electronic vintage gauges

The FFR vintage electronic gauges are backlit with LEDs (re-confirmed today with FFR tech support).

The rheostat in the FFR headlight switch works by cutting the voltage, which in an incandescent bulb (and the "regular" gauges) means less current and less energy, hence less light. So non-LED gauges work fine with the headlight switch "out of the box".

LEDs are either on or off, with the transition measured in nanoseconds. Perceived brightness in an LED is controlled by turning them on and off rapidly (above a hundred hertz) in conjunction with the duty cycle. Thus, you can dim LED brightness but it requires control electronics, not just a simple rheostat.

As a result, unless electronic control is added, the headlight switch will just turn on the LED electronic gauge illumination at some point without any dimming.

Anyone have a solution to this that can be appended to the headlight switch rheostat?
 

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Kriss Motors
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this might work


AUTO METER 9114 LED Lighted Gauge Dimmers
Net Price : $28.60

Description
  • This compact separate module is designed to allow for isolated dimming for all Auto Meter gauges utilizing LED lighting technology separate from your vehicle's OEM dash. These Auto Meter LED lighted gauge dimmers allow you to dim your LED gauges separately from other factory dashboard gauges. These dimmers are compatible with all other LED-lit instruments, and are capable of adjusting up to seven gauges together.
Item Features
  • Rotary Switch Actuation Style with Constant Circuit Activation
  • Plastic Switch Material with Black Switch Finish
  • Sold individually
=====

Not as elegant as controlling directly through the headlight switch, but perhaps an underdash mount would be OK.
 

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I've got it


AUTO METER 9114 LED Lighted Gauge Dimmers
Net Price : $28.60

Description
  • This compact separate module is designed to allow for isolated dimming for all Auto Meter gauges utilizing LED lighting technology separate from your vehicle's OEM dash. These Auto Meter LED lighted gauge dimmers allow you to dim your LED gauges separately from other factory dashboard gauges. These dimmers are compatible with all other LED-lit instruments, and are capable of adjusting up to seven gauges together.
Item Features
  • Rotary Switch Actuation Style with Constant Circuit Activation
  • Plastic Switch Material with Black Switch Finish
  • Sold individually
=====

Not as elegant as controlling directly through the headlight switch, but perhaps an underdash mount would be OK.
I've got one of these units under the dash and it works perfectly.

Cheers
Steve
 

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That's better than the $50 I found when I first got my ultralites installed! I'll still make my own though...

Oxide - the issue that those links miss is that there is poor uniformity of brightness vs current between LEDs from different batches, and that the curves can be very different. That and the schematics showed either a single LED or a cascade of LEDs - in our case the LEDs are all in llel (multiple LEDs in multiple gauges).

I did try to vary the current, and the gauges were FAR from uniform - all seemed to be similarly bright when "full on", but as I dimmed some gauges (same vendor, same line) would go dark before others had dimmed appreciably.

If you're anal and want a solution that lets you dim everything uniformly, I think PWM (like the box above) is the way to go.... I'll draw up an astable 555 cct with a duty cycle control.... should be like 6 parts and cost $3 max.
 

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Speedhut Gauge Lighting

Ok Fellas,

Let me fill some of you in about the Speedhut/F5/Kirkham gauges. First off, there seems to be some confusion about the way we backlight our gauges. All our competition uses either LED or filament bulb type lighting which gives hot spots and, like mentioned in some of these forums, is hard to dim. Our backlighting uses an Electro Luminescence dial backing which causes the entire dial face to glow except where the dial face is black. We provide a DC to AC invertor with every gauge and set that powers the dial backlighting. All a customer would need to do to dim the backlighting is tie the inventor input power wires to the headlight rheostat. We could even provide a stand alone rheostat upon request. The pointer lighting is also dimmable by tying a separate lighting wire into the headlight rheostat.

Let us know what we can do for you.
Wade
 

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Kriss Motors
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Shoehorn81,

Very interesting. I don't recall getting a "DC/AC inventor" (do you mean "inverter"?) with my gauge set included in the Mk3.1 Complete Kit. Can you post a photo of what it looks like? Also a sample wiring diagram?

FFR tech support, as of today, was not aware of this capability and is just advising those with the LED/electronic gauges that dimming is not an available feature. Would be good to update them; this is an upcoming issue for many who are now receiving kits with the new gauges.
 

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Kriss Motors
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photo not posted
 

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FFCobra Craftsman
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Here is photo of the invertor I mentioned before. The output that powers our gauge lighting is proportional to the voltage input.

Could you also post a wiring diagram when you repost the picture?
I assume you are an employee of Speed Hut, correct?
I love the product with the exception of the non lit clock needles.
Thanks for your help.
 

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I am an employee of Speedhut, actually the VP of Engineering over here.

Hopefully this attachment will be available to view.

Gauge_kit_inverter.jpg

Black wire is ground.
White wire goes to the headlight rheostat dimming output or can be run to a switched 12 volt supply.


Wade Snarr
Revolution Gauges by Speedhut
 

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I double checked my wiring last night and I have both white wires (from the AC module and the 3-wire connector) connected to the dash lighting feed wire from my wire harness. And if I remember right, the needle dims but the gauge face doesn't. Should I check something else? When I put my dash back on the car, I'll double check. :confused:

thanks,
Sean
 

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I have the white wire connected to my head light switch dimmer. The lights are either on or off, no dimming. I've check the voltage output from the dimmer and it varies with the dimmer position My previous gauges where lite with incadescent bulbs and the lights were dimming perfectly.
 

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I double checked my wiring last night and I have both white wires (from the AC module and the 3-wire connector) connected to the dash lighting feed wire from my wire harness. And if I remember right, the needle dims but the gauge face doesn't. Should I check something else? When I put my dash back on the car, I'll double check. :confused:

thanks,
Sean
Sean,

If you have a volt meter, could measure the output of your dash lighting feed wire at the brightest and dimmest settings and let me know what they are?

Wade
 
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