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> Dash lights are out
Geezer914
post Oct 18 2024, 09:46 AM
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Dash lights are out, converted to LED bulbs. Fuse or restart? If the reostat is not working is the a way to wire the dash lights to bypass the reoatat. Car is 1975 with the late headlight switch.
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VaccaRabite
post Oct 18 2024, 09:50 AM
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Turn the headlight knob. The LEDs (at least the ones I installed) are either on or off. There is no dimmer with them.

So try turning the knob and see if they turn on.

Zach
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Spoke
post Oct 18 2024, 10:10 AM
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If you've changed every bulb to LED, try changing one back and see if it lights up. Like Zach said, the dimmer doesn't work with LEDs and will only go on-off as the knob is rotated.
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davep
post Oct 18 2024, 11:10 AM
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LED's are diodes, so they are polarity sensitive unlike filament bulbs. Try a test with a battery to see if the bulb case is ground.
I hope you did NOT change the alternator light bulb; that is one filament bulb that you CANNOT change.
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Geezer914
post Oct 18 2024, 11:15 AM
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Alternator bulb was not changed. LED lights were changed last year and worked up till now. Got in the car this morning just before dawn and no dash lights. Headlights and parking lights ok. Turned the knob and no luck. Tried it a few times. Is there a fuse I can check before I pull the switch and is there a way to bypass the rheostat? Searched and one person said he hooked up the gauge lights to the parking lights on the switch but did not say how. So when the parking lights get switched on the gauge lights work.
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Geezer914
post Oct 19 2024, 06:12 PM
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Replaced headlight switch with a spare and still no dash lights! Checked the fuses, all good. Where to go from here? Replaced all the gauge lights with LED bulbs except the alternator light last year. Got in the car yesterday morning and headlton but no gauge lights.
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Spoke
post Oct 19 2024, 10:50 PM
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Sorry can't give a single 'check this' item for you.

My troubleshooting for this is quite basic. Follow the wires from the battery to the bulbs using your schematics. Follow the voltage. Start at the battery and follow your schematic to the headlight switch then to the bulbs. The voltage starts at the battery and fails to make it to the dash bulbs. Find where the voltage stops.

'74 914 Schematic
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Geezer914
post Oct 20 2024, 10:13 AM
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Tested the new headlight switch. Parking lights and headlights work. Rheostat works. When I turn on the headlights, the fuse blows, so I have a short somewhere.
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76-914
post Oct 20 2024, 10:27 AM
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QUOTE(Geezer914 @ Oct 20 2024, 09:13 AM) *

Tested the new headlight switch. Parking lights and headlights work. Rheostat works. When I turn on the headlights, the fuse blows, so I have a short somewhere.

Maybe ID which circuit by pulling away one connection at a time from the light switch. I've read about some LED brands that fit quiet loosely and can short out if not centered in the socket. (IMG:style_emoticons/default/beerchug.gif)
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Dave_Darling
post Oct 20 2024, 07:15 PM
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Has anyone messed with your rear bumper lately?

If you swap the connections on the license plate light, it will pop the fuse that lights the gauges.

... Not that it took me two weeks of hunting to figure that out or anything... (IMG:style_emoticons/default/wink.gif)

--DD
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Geezer914
post Oct 21 2024, 02:49 PM
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How would the license plate lights effect the dash lights? The license plate lights are the grey wire on the headlight switch 56k . All the dash lights are connected to the rheostat 58a, multiple black wires with a black/ blue stripe wire.
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barefoot
post Oct 21 2024, 03:57 PM
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QUOTE(Spoke @ Oct 18 2024, 12:10 PM) *

If you've changed every bulb to LED, try changing one back and see if it lights up. Like Zach said, the dimmer doesn't work with LEDs and will only go on-off as the knob is rotated.


My LED instrument illumination bulbs are dimmable. Think i got them on Amazon.

2 types for different bulb holders, sorry one in each image.


Attached Image

Attached Image
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87m491
post Oct 22 2024, 06:55 AM
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QUOTE(Spoke @ Oct 18 2024, 08:10 AM) *

If you've changed every bulb to LED, try changing one back and see if it lights up. Like Zach said, the dimmer doesn't work with LEDs and will only go on-off as the knob is rotated.


True a few years back, but there are dimmable LEDs out there now and I have some in my 914.
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Geezer914
post Oct 22 2024, 12:05 PM
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When I turn on the lights, #7 fuse blows. So it's not about dimming, there is a short somewhere. The LED's have worked fine since I installed them last year. All of a sudden,I am blowing fuses. (IMG:style_emoticons/default/confused24.gif)
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Superhawk996
post Oct 22 2024, 12:22 PM
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QUOTE(Geezer914 @ Oct 21 2024, 04:49 PM) *

How would the license plate lights effect the dash lights? The license plate lights are the grey wire on the headlight switch 56k . All the dash lights are connected to the rheostat 58a, multiple black wires with a black/ blue stripe wire.


Schematic will answer that question.

If you don’t know how to read the schematic, I’ll post instructions on how to read it.

FWIW - I’m not a fan of the current flow diagrams so I get it if you’re not familiar with how to read them.
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Geezer914
post Oct 22 2024, 04:54 PM
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All the dash lights have a black/ blue stripe and a black wire going to the light socket. I will have to separate the multiple wires on the one side of the headlight switch rheostat. Then check continuity of each wire from the gauge lights to the switch. Should I use a test light or ohm meter?
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Geezer914
post Oct 23 2024, 01:28 PM
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Separated the 4 wires on post 58a on the headlight switch (75 914). One wire is black/purple stripe that connects all the dash lights. There are 3 black/blue wires, where do they connect too? Since they are on a dimmer do they connect to the hazard switch, fog light switch, and ? (IMG:style_emoticons/default/confused24.gif) The wires to the dash lights checked out, so I am assuming one of the black/blue stripe wires has the short that trips the fuse.
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Literati914
post Oct 23 2024, 01:55 PM
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QUOTE(Geezer914 @ Oct 23 2024, 02:28 PM) *

Separated the 4 wires on post 58a on the headlight switch (75 914). One wire is black/purple stripe that connects all the dash lights. There are 3 black/blue wires, where do they connect too? Since they are on a dimmer do they connect to the hazard switch, fog light switch, and ? (IMG:style_emoticons/default/confused24.gif) The wires to the dash lights checked out, so I am assuming one of the black/blue stripe wires has the short that trips the fuse.


Not sure on the '74.. but on my '72 the Bk/Bl wire was the dash illumination circuit. Maybe the wrong wire was hooked up when you switched over to the LEDs? I think BK/Pu powers the tach
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Geezer914
post Oct 23 2024, 03:59 PM
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The black/purple stripe wire was together with the black/blue stripe wires. I never touched the wires. Anyone have pictures of their headlight switch with the wires connected?
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Geezer914
post Oct 23 2024, 07:58 PM
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QUOTE(Superhawk996 @ Oct 22 2024, 02:22 PM) *

QUOTE(Geezer914 @ Oct 21 2024, 04:49 PM) *

How would the license plate lights effect the dash lights? The license plate lights are the grey wire on the headlight switch 56k . All the dash lights are connected to the rheostat 58a, multiple black wires with a black/ blue stripe wire.


Schematic will answer that question.

If you don’t know how to read the schematic, I’ll post instructions on how to read it.

FWIW - I’m not a fan of the current flow diagrams so I get it if you’re not familiar with how to read them.


The schematic shows 2 black/blue stripe wires at 56a but I have 4???
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