1984 - No dash lights at night?

[DBROS]

I have an 84 that just developed a strange problem. My cluster is nice and bright during the day (car only has 26k original miles) all gauges read correct, when night time falls or when I cover the light sensor I can barely see my gauges - did I blow a fuse? I turn the the light dimmer switch and nothing changes.

Also, I cannot see any of my heater controls or gauge controls on the dash at night, are those supposed to be lit? I can't recall as I've only owned the car for a few months and only drove it at night a few times.

Thanks for the help!

Dennis

 

[tonylong]

Aha. The light sensor 'brightens' the cluster when ambient light is brighter. Try shining a light directly into the sensor.
It should get brighter (if done at night or in dimmer light).
It's normal for the cluster to dim when the the light switch is turned on, to prevent the cluster from overpowering your eyes' night vision.
It could also occur if a hot blonde peers in over your shoulder at the cluster. Of course you may not notice then.

 

[tonylong]

The switches for the guage selections aren't lit, the Heater/AC and Fan Speed is - at least it is on my Auto-Temp Control unit. Lesser temp units may not be lighted.

 

[DBROS]

Light sensor does work for dash illumination during the day

The lights do work during the day, if I start the car at night, they are bright for 5 seconds and then dim to hardly visible, turning the light/dimmer swicth has no effect - if I flash a light on the sensor the dash lights do illuminate at night - problem some where - fuse?

Dennis

The switches for the guage selections aren't lit, the Heater/AC and Fan Speed is - at least it is on my Auto-Temp Control unit. Lesser temp units may not be lighted.

 

[tonylong]

The lights do work during the day, if I start the car at night, they are bright for 5 seconds and then dim to hardly visible, turning the light/dimmer swicth has no effect - if I flash a light on the sensor the dash lights do illuminate at night - problem some where - fuse?

Dennis

Spunds like a sensor issue if flashing the sensor lights em up. Maybe a bad sensor, or maybe the sensor is dislocated. I've never inspected my to know how it's mounted. If lighting the sensor maintains brighter dash lights then the sensor is likely OK. If the dash is still intermittent, then check the sensor.
Do the lights flash at other times - I'm thinking a loose connection in the dash light system too.
Most of the dash is axccessible once you remove all the cover pieces, and you can still drive the car OK. I drove with all the dash plates and the top pad off for months while I played with stuff. Going UNDER the dash is another whole thing.

 

[CorvetteArchives]

Have you tried turning the parking/headllights ON?
Sounds silly but the sensor is there for a reason. I remember reading (gordon Killebrew is think) how GM added the sensor so people would rememebr to turn their lights on at night.
If the dash had remained at full day brightness people wouldnt remember come dusk.
If it lights normally with headlights on its working exactly as designed.

 

[tonylong]

The lights do work during the day, if I start the car at night, they are bright for 5 seconds and then dim to hardly visible, turning the light/dimmer swicth has no effect - if I flash a light on the sensor the dash lights do illuminate at night - problem some where - fuse?

Dennis

Uh Oh maybe I misunderstood you. When you related what happens when driving at night, I presumed that you had turned the head or park lights on. My response was based on that. If you havn't turned lights on, then ummm, I don't know what happens to panel brightness.
I don't believe I've ever driven at night without headlights. If I have, then I probably was in no condition to notice much of anything.

 

[CorvetteArchives]

Tony...yeah confusing...I was reading your response which obviously does make sense...then went....hmmmm..IS there a problem?
However, it is a problem which "just developed" .... there IS a fuse just for instrument panel lamps.....

Here are the relevent wiring diagrams...once again courtesy of mrbill! :cool
http://http://misterbill.homeip.net/vette/wiring/instrument%20cluster%20inputs_outputs.jpg

http://misterbill.homeip.net/vette/wiring/inst panel illum.jpg

 

[tdr1919]

This 99% a problem in the light sensor or related circuits. living on the east coast with both humidity & temp changes our older vettes are subject to corrosion in the cable/wire harnesses and also problems with solder connections on the printed circuit boards. I have already repaired the boards on my control panel, (dash lights went off & on intermittantly)
I think if you first remove the connectors to the instrument panel and clean both end of the connections with electronic tuner cleaner (radio shack) see if this helps. If not most likely there is a connection or cold solder on the circuit boards.
Tom

 

[LORR1943]

I DON'T KNOW IF YOU FOUND YOUR TROUBLE YET OR NOT, BUT I HAD THE SAME PROBLEM. COME TO FIND OUT THE FUSE WAS BLOWN AND THAT FUSE ON MY CAR(89VERT)ALSO POWERS THE TAIL LIGHTS. THE REASON MY FUSE WAS BLOWING WAS MY SHIFTER(AUTO)HAD PINCHED THE SHIFT INDICATOR LIGHT HARNESS UNDER THE CONSOLE. ALSO BE ADVISED THAT THE NIGHT/PHOTOSENSOR CIRCUIT IS SEPERATE FROM THE DASH/INFO PANEL CIRCUIT.