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Discussion Starter #1
ok, so long story short, I installed a pair of fog lights using oem wiring.

I messed with the panel light dimmer to give power to the fog light switch(by tapping the green and/or purple wire). Neither worked so I gave up.

Anyway, so after the attempt, I noticed that the clock light is acting weird. When I turn on the car, the clock back light would light up, which I think it does no matter what, correct? But when I turn on the head lights, the clock back light turns off. so basically, i can see the clock during the day when my head lights are off, and can not see the clock at night when head lights are on.

any idea what's going on here?
 

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I noticed that the clock light is acting weird. When I turn on the car, the clock back light would light up, which I think it does no matter what, correct? But when I turn on the head lights, the clock back light turns off. so basically, i can see the clock during the day when my head lights are off, and can not see the clock at night when head lights are on.
When the headlights are turned off, the clock back-lighting is at a fixed value. The brightness of the clock is not adjusted by the rotary dimmer control. However the dimmer control will still have an effect on the instrument brightness when the headlights are off.

When the headlights are turned on the back-lighting of the clock can be adjusted from totally off to maximum with the rotary dimmer control.

Does your dimmer control adjust the brightness of the instruments normally when the headlights are on? Does it adjust the brightness of the instruments when the headlights are off? Is it only the clock that appears to be dark?
 

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Discussion Starter #3
When the headlights are turned off, the clock back-lighting is at a fixed value. The brightness of the clock is not adjusted by the rotary dimmer control. However the dimmer control will still have an effect on the instrument brightness when the headlights are off.

When the headlights are turned on the back-lighting of the clock can be adjusted from totally off to maximum with the rotary dimmer control.

Does your dimmer control adjust the brightness of the instruments normally when the headlights are on? Does it adjust the brightness of the instruments when the headlights are off? Is it only the clock that appears to be dark?
ok, so the dimmer control adjust the instruments when the headlights are in on and off position. The dimmer control does not adjust the clock brightness on and off. and it is just the clock.

I forgot, is there a light on the dimmer control itself?
 

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ok, so the dimmer control adjust the instruments when the headlights are in on and off position. The dimmer control does not adjust the clock brightness on and off. and it is just the clock.

I forgot, is there a light on the dimmer control itself?
That's a tough one. It seems that the dimmer is OK because it controls the brightness of everything else. It also seems that the clock back-light is connected and working, because it turns on when the headlights are off.

Just to confirm, the lighting of the radio display is working normally and can be adjusted with the rheostat dimmer?

How about the lighting of the switches such as "Auto LSD" or "4WD Control" or "Downhill Assist" or the "Hazard Warning Switch", or the "Seat Heater Switch(s). Do you see these light up at night when the headlights are on?. How about the shifter console?.

If you could find one other light that isn't working it would help to pinpoint the cause.
 

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Discussion Starter #5
That's a tough one. It seems that the dimmer is OK because it controls the brightness of everything else. It also seems that the clock back-light is connected and working, because it turns on when the headlights are off.

Just to confirm, the lighting of the radio display is working normally and can be adjusted with the rheostat dimmer?

How about the lighting of the switches such as "Auto LSD" or "4WD Control" or "Downhill Assist" or the "Hazard Warning Switch", or the "Seat Heater Switch(s). Do you see these light up at night when the headlights are on?. How about the shifter console?.

If you could find one other light that isn't working it would help to pinpoint the cause.
well, that's the problem, EVERYTHING else works. all the dash buttons, the heat and fan controls. only the clock is not working.
 

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well, that's the problem, EVERYTHING else works. all the dash buttons, the heat and fan controls. only the clock is not working.
First thing is, I am not 100% sure if the clock lighting is LED or electroluminescent panel (ELP). The diagram does not show a converter circuit (required for ELP) , but it may be contained within the clock assembly.

According to the wiring diagrams, the clock back-lighting is in parallel with the switch lights that I mentioned. If only the clock didn't light up, I would suspect that the LED/ELP was toast. But then it does light up when the headlights are off, proving that the LED/ELP is good.

My last suspicion is this. When the headlights are off, a higher voltage is applied to the LED/ELP causing it to fire up. When the headlights are on the voltage is reduced, and is not sufficient to trigger on the LED/ELP.

Have you moved the rotary dimmer through the entire range (including the detent position)? Have you tried it with the engine running which would provide a slightly higher voltage?

If that doesn't help, you will need to get at the wiring behind the clock and measure the voltages across the LED/ELP with both the headlights on and off, to see if the voltage is low or missing entirely.
 

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Discussion Starter #7
First thing is, I am not 100% sure if the clock lighting is LED or electroluminescent panel (ELP). The diagram does not show a converter circuit (required for ELP) , but it may be contained within the clock assembly.

According to the wiring diagrams, the clock back-lighting is in parallel with the switch lights that I mentioned. If only the clock didn't light up, I would suspect that the LED/ELP was toast. But then it does light up when the headlights are off, proving that the LED/ELP is good.

My last suspicion is this. When the headlights are off, a higher voltage is applied to the LED/ELP causing it to fire up. When the headlights are on the voltage is reduced, and is not sufficient to trigger on the LED/ELP.

Have you moved the rotary dimmer through the entire range (including the detent position)? Have you tried it with the engine running which would provide a slightly higher voltage?

If that doesn't help, you will need to get at the wiring behind the clock and measure the voltages across the LED/ELP with both the headlights on and off, to see if the voltage is low or missing entirely.

Thanks, I guess I'll have to rip it apart sometime. But yea, the rotary dimmer works through all ranges, for every lgiht except for the clock. I mean is the clock even suppose to light up when the head lights are off? weird?
 

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Thanks, I guess I'll have to rip it apart sometime. But yea, the rotary dimmer works through all ranges, for every lgiht except for the clock. I mean is the clock even suppose to light up when the head lights are off? weird?
When the headlights are off

  • The clock should be on
  • It will be at maximum intensity
  • The variable control has no effect on the clock display (but main instruments can be adjusted)
When the headlights are on

  • The brightness of the clock is controlled by the variable control
  • It will go completely off if the control is rotated very low

In my Limited with the JBL stereo, the clock and stereo display lighting track each other in all cases (display only, button lighting is off when headlights off) . Does your stereo lighting follow the patterns described above?
 

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Discussion Starter #9
When the headlights are off

  • The clock should be on
  • It will be at maximum intensity
  • The variable control has no effect on the clock display (but main instruments can be adjusted)
When the headlights are on

  • The brightness of the clock is controlled by the variable control
  • It will go completely off if the control is rotated very low

In my Limited with the JBL stereo, the clock and stereo display lighting track each other in all cases (display only, button lighting is off when headlights off) . Does your stereo lighting follow the patterns described above?
everything you said about with head light off, is correct on my Rav4.

with head lights on, does not apply because the clock is off, no matter what position the rotary dimmer is. I have an aftermarket Navi, the screen and button turns on when head lights are on, but the brightness is fixed.
 

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Hi I have the same thing my clock light goes out when i put the headlights on can anybody help in this matter ? please,thanks, Ronnie
 

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Hi I have the same thing my clock light goes out when i put the headlights on can anybody help in this matter ? please,thanks, Ronnie
Turn your dash dimmer control to full brightness.
 

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I did that nothing for some reason the clock light just goes out when I put my headlights on,this only started 1 week ago and I check every fuse there is all good a really mistery thanks for the help,though, Ronnie
 

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I was looking for the solution to the same problem and hit that forum. My 2005 RAV4 has all dashboard and radio lights on. Only clock does not illuminate and ashtray light does not work.
Did anyone here found the issue and solution?
 

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I was looking for the solution to the same problem and hit that forum. My 2005 RAV4 has all dashboard and radio lights on. Only clock does not illuminate and ashtray light does not work.
Did anyone here found the issue and solution?
It does not look like any one has found the solution yet that we know of.
 
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