Instrument cluster backlight out.

[HughLouisDewey]

1996 D1 SD

Hey all, tried searching for this, but came up empty. I recently did some cleaning up of my battery pos and neg terminals and connections, which fixed a problem I was having of weak electrical power in the vehicle (dim lights, interior gauges flickering and dimming when lots of stuff was turned on), however the after effect was that the instrument cluster backlight that illuminates the tach and speedometer etc. has gone out. When I turn the headlights on, I get no illumination on the cluster, and can't see my speed, RPM, etc. at night. I thought a fuse might have blown, but the the manual says that fuse #14 under the driver's footwell controls the instrument cluster, clock, and secondary SRS. So I pulled and probed that fuse, which was fine. This caused another problem of my SRS light being on all the time, which I couldn't resolve, so I just took the whole instrument cluster out and removed the two bulbs to the SRS light. Now I'm worse off than I was, and can't figure out why my gauge backlight is still out. I still have all my individual warning lights (check engine, brake, low fuel, etc.), just no backlight (green I think) to the needled gauges.

Do I need to pull the instrument cluster back out and replace a bulb or something inside there, or is there another fuse somewhere for this particular cicuit?

Thanks for the help.

 

[boxster]

Maybe headlamp/ turn signal switch has failed?

 

[HughLouisDewey]

Maybe headlamp/ turn signal switch has failed?

It's possible, I guess. The headlights/turn signals still work fine, so maybe there's a problem down stream between that switch and the instrument backlight. I just don't like how it coincided with my cleaning up all the battery cables. It also annoys me that when I pull the #14 fuse that is supposed to be for the instrument panel/clock/SRS, for some reason the clock is still on. Maybe I'm looking at an incorrect fuse diagram, and there's another fuse for the backlight somewhere.

 

[boxster]

Saw a video about the symptom check for electric short of the glove box lamp.

 

[boxster]

The T/S switch is fairly simple to replace 3 screws on the shroud and 2 on the switch you’ll need a right angle Phillips head driver for those lift the lower screw tab and slides out then remove the electrical connectors.

 

[boxster]

You could try the wiggle test a the t/s switch connectors and move the switch at the same time before buying parts.

 

[Tugela]

Maybe headlamp/ turn signal switch has failed?

If that's the case, wouldn't the tail lamps also be out? I experienced this combination of failures in conjunction with the turn signal switch on my D1.

 

[robertf]

is the dimmer rolled down all the way?

 

[HughLouisDewey]

is the dimmer rolled down all the way?

No, the dimmer wheel doesn't seem to have any effect. But that's a good place to check; I'll try messing around with that next, maybe unplugging it entirely will do something.

 

[robertf]

does the clock or radio brightness change when the lights are on?

if its an auto, do the shifter lights go out when the lights go on?

 

[HughLouisDewey]

does the clock or radio brightness change when the lights are on?

if its an auto, do the shifter lights go out when the lights go on?

The clock has no illumination at all; hasn't since before I got the Discovery. Can barely see the time unless its really bright out. I'm not sure if there's an internal bulb or something that's burnt out.

The radio is an aftermarket that doesn't change illumination with the headlights anyway. It's a Continental stereo that I don't think even has that function.

It's an auto, but I don't see any illumination on the shifter panel whether or not the headlights are on.

 

[pdxrovermech]

my back lighting on my disco went out for when my battery wore through a wire in the battery tray. I believe it popped the fuse for either my left or RH running lights, which also handled the illumination.

 

[HughLouisDewey]

my back lighting on my disco went out for when my battery wore through a wire in the battery tray. I believe it popped the fuse for either my left or RH running lights, which also handled the illuminati

Hmm, I might pull the battery to see if anything odd is going on underneath. Unfortunately, all my exterior lights are working fine, and I probed every single fuse under the driver's kick panel and in the engine bay and couldn't find a single one blown. I think my only option is going to be to get the instrument cluster back out of the dash and see if I can figure out where the actual bulb itself is; maybe by my cleaning the battery cables and introducing more juice into the system, that particular bulb blew.

 

[HughLouisDewey]

does the clock or radio brightness change when the lights are on?

if its an auto, do the shifter lights go out when the lights go on?

Update to this: I pulled the clock out of the dash and replaced the bulb with THIS one from O'Reilly, which worked great, now I can read the clock all the time. The clock illumination, however, does not change depending on if the headlights are on or off. They flicker for a fraction of the second when I turn the headlights on, but no change in the brightness level.

 

[WaltNYC]

check rear stop and brake bulbs. the dash is telling you you have a problem at the rear of the truck

 

[HughLouisDewey]

check rear stop and brake bulbs. the dash is telling you you have a problem at the rear of the truck

Gotcha, I'll focus on the back then. As far as I can tell, all the brake lights, turn signals, reverse lights, etc. are all functioning, but could there still be a problem even if everything looks like it's working okay? I really hated getting into that assembly last time I had a bulb out. I had to completely remove the rear jump seats to even get access.

 

[German Gruner]

Instrument panel lights and clima controls light are connected to rh sidelamps. If all sidelamps arround are ok, then may be bulbs ( there are very few), are blown.

 

[HughLouisDewey]

Okay, thought I'd do an update for posterity. After checking every bulb on the car and removing/cleaning the rear light assemblies, I still had no gauge lights. Incidentally, I also replaced both of the gear shifter panel bulbs, which is nice, but no gauge lights. I removed the gauge cluster again and checked the individual bulbs for the backlight (they had a green plastic cover for the color). All the bulbs worked with 12v directly on them, so I removed the dimmer potentiometer module, sprayed it out with contact cleaner, then reassembled everything. Interestingly enough, I briefly got the backlights to come on, but it was finicky. I rolled the headlight switch forward sort of halfway, then back and forth a bunch, and now the gauge lights are seemingly working. I'm believing that it's a worn out switch in the stalk (as someone previously said), so when I can I'm going to remove the stalk and see what can be done about it.

Does anyone know if the stalk can be opened/cleaned/fixed, or is it a replace only type thing?