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Not totally sure what has happened here, and have searched to no end. Noticed when turning on the parking lights/headlights, the lights for everything in the center (console light, HVAC lights, 4wd light switch, etc) does not come on. The floor light on the passenger side does not come on, but driver side does, and finally, the clock works when I dont have the lights on, but as soon as I turn parking/headlights on, the clock, which would normally dim at this point, goes out.

I have researched the possibility of a fuse, but this seems to be different functions, and why would those not work, yet the dash lights and driver floor light does work.

First thoughts had been the possibility of one of the dimmer lights on the radio wiring harness getting grounded out, but cannot determine that occurring. Truck does have an aftermarket stereo in it. Have tried tracing the wiring diagrams as well, but nothing as of yet.

Any thoughts folks?
 

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I feel strongly that it is something in the "combination gauge" AKA the gauge cluster. I caused this exact problem while dicking around behind the dash with the info center control wires. I shorted the wrong two, and it's been doing it ever since.

Eventually i'll sign up for TIS, download the schematic for the combination gauge and figure out what I let the smoke out of.

You though, are very likely going to end up getting a new combination gauge from the dealer under warranty.
 

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The gauge cluster (speedometer, tach, etc) all work as they are supposed to. The problem is in everything right of the steering wheel. None of the HVAC control lights come one, nor does the passenger side floor light, or the orange center console light for the cup holder area. The clock/temp/mpg shows when the lights are not on, but with parking lights or headlights on, where that display should dim, it turns completely off. Because of all of this, I am not suspecting a fuse, but am still suspecting its something from the dimmer wire (orange/white) on the radio wiring harness. I am not sure which wiring schematic to look for to trace it back, and see where it may have effected what systems. I have a copy of all wiring schematics for the truck, just a matter of finding it.
 

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Same exact thing happened to me. It happened cause I did the same as the other guy said, "shorted a wire" while installing aftermarket DVD head unit, thats why they always tell you to disconnect the battery!

Yes there is a relay in the gauge cluster that got smoked. They have to replace the gauge cluster. Which is a PITA cause they cant just order the part, they need to call Denso with the mileage so they can program it first.

Might not wanna have that aftermarket HU in there if you go for a warranty claim.
 

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Henry T - Thanks for the info. I bet I can fix my gauge cluster myself. I've done a buttload of PCB work in the past. Either that or see if I can get the dealer to order a set of Optitron gauges and pay the difference.

Whistlepig - The schematic you're looking for is the "combination gauge", not just the block diagram though, the one with every resistor, diode, cap and transistor. I know the information for the driving computer comes directly from there, and that the combo gauge is connected to the CAN. It appears a lot more goes on inside than just what the gauges display.
 

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I have the same problem when I got my '00 Tundra TRD. The gauge cluster light is not on nor any lights from the center console (temp/ac/fan). Some one told me it's because of the orange (illumination) wire in the back of the HU. Anyone know if I just clip that wire off then everything should work? I've checked all the fuses and bulbs and everything is good but no lights at all. I can't see anything or how fast I'm goin at night so any help would be much appreciated.
 

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Discussion Starter #7
Follow up on this little ordeal: took truck in, was first told it would take days for them to get around to pulling the dash, because it was such hard work. Told them it could have it done in less than 10 minutes. The response was "we like to do a good, careful job, and we know you had after market equipment in there, it was noted in the computer the first time you brought it in for an oil change 2 years ago, and more than likely this is what caused it, and it wont be covered under warranty". I asked if that were the case, wouldnt I have had this problem long ago if it was after market equipment that caused it, and furthermore, you know I have had that dash off, and there isnt a mark on it. To the point you even commented previously on how good a job had been done on the installation! I was told we arent going to argue with you and was further ignored. Was even stated that they could no longer provide dealer vehicles for the duration of service, even though I paid for the extended warranty, which that was a part of. I could understand if I was rude or even snippy with them, but I was nothing but polite from the word go!

So long story short, thats their take on it. Any excuse they could find to not work on it is what it has amounted to. Sad, in that here I am getting ready to drop a good $30k+ on a new Highlander. That little ordeal certainly cost them that sale, and any future sale on my part, not to mention now I am really wondering if I was to stay with the Highlander, and go for a Honda Pilot instead.

Anyone know of a way to bypass the relay on the dash cluster, even to where the HVAC and Clock lights would stay on all the time if need be?
 

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Not all dealers are such dinks. But it sounds like you have a lousy service department, or maybe service manager. Have you talked to the S.M. already? If so, I'd take it to the general manager or owner of the dealership. Point out how many Toyotas you've had, and ask if it's common practice to alienate customers?
In terms of your problem, I'll have to assume you've excluded the dash light dimmer switch itself as the culprit? That is not a hard one to bypass, and if that's all it is, you can easily replace it. Just a thought.
 

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I am suspecting that when the relay trips for the lights to turn on, it lowers the voltage to the clock lights to allow more voltage to bypass the light in the clock. Someone needs to pull up the clock and look at the wiring behind the clock - this will confirm if in fact, the stalk is causing the clock to dim and thus look like it was off. In the night time I can see my clock just perfectly when my headlights are on , just not when in daylight. :)

Hint: look for a resistor in the back of the clock or the relay switch wiring to confirm if this indeed prevents the voltage from being passed on to the clock cluster.

Sanosuke!
 

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The illumination circuit ground runs into the combination meter(gauge cluster). Poor engineering! If there is a short then a fuse should blow not your combination meter!

I had the same problem with my illumination lighting. I research the wiring diagrams from Toyota TIS and came up with a quick fix. I spliced into the illumination ground and ran a new ground point. Much cheaper then $850!!

Let me know if anyone is still having problems with the illuminations. I can foward you the wiring diagram and my quick fix.
 

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Discussion Starter #14
PM sent! :)
 

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The illumination circuit ground runs into the combination meter(gauge cluster). Poor engineering! If there is a short then a fuse should blow not your combination meter!

I had the same problem with my illumination lighting. I research the wiring diagrams from Toyota TIS and came up with a quick fix. I spliced into the illumination ground and ran a new ground point. Much cheaper then $850!!

Let me know if anyone is still having problems with the illuminations. I can foward you the wiring diagram and my quick fix.
Agree poor engineering here should not happen like that.
 

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I could use the "quick fix" info as well. Thanks in advance to anyone who can help me out.

If you have the info, please send it to:
[email protected]

I'm trying to get a friend squared away without have to go to the dealership (truck is out of warranty).
 

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Well I did this repair and ran a ground wire from pin 37 to ground and my lights are working again. One thing I cannot remember is if the HVAC, switch button lights, and clock and temp dimmed also with the Instrument cluster? My Instrument cluster dimes and brightens as it always has but the rest of my lights do not now that I have run this ground wire to get my lights back without replacing the instrument cluster.
 
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