I think I have reached my wit's end on this seemingly unsolvable issue; my 2001 OBW VDC has a clock backlight that is not illuminating.
The background:
When I became the owner, there were additional lights out in the cluster so I decided to replace ALL of the lights in the cluster. However, I noticed the clock backlight did not come on. So, I checked all pertinent fuses and pulled the bulb. Tested bulb. Bulb is good. Examined contacts on cluster. No visible damage. Checked continuity between various points on board and between contacts when bulb was twisted in and found no issues. Reinstalled and still no illumination
I kind of gave up at this point because, hey, it isn't the most serious of issues and the vehicle needed and work to make it seaworthy.
At some point in between this I am spinning around in the snow and the clock light illuminates (no idea if spinning in snow is relevant). Okay, so now it's taunting me. Eventually it goes back out one day, who knows how long it lasted, a few hundred miles maybe if that. Anyway, now I wanted to fix it even more, especially because it's annoying to look at a dash with a dark rectangle in it. So, I pulled up a wiring diagram from a library resource (I think it is Haynes) and became disheartened because it seemed tightly integrated into other working circuits that I didn’t know where to begin. I had to do the other work on the car so I gave up on this until recently finishing the major work. Right before I parked the light had randomly turned on again for a little bit. This was after I undid everything again (with my lacking of electrician’s skills I have to revert to a caveman style of simply unplugging and plugging things back in). I do all of this with the battery disconnected so I have no idea if it was simply another random occurrence.
Notable observations:
A previous owner or mechanic has tapped into a few wires and electric taped over the exposed wires. I tried for hours to teach myself how to understand Subaru’s FSM wiring schematics (power distribution, ground distribution, etc.) and I determined that there are only two wires that more or less directly go into the instrument cluster (it seems that every wire is connected in this vehicle, which makes sense if you think about it : ). One of them is found on SMJ i1 (of which I cannot find a FSM page that details each pole’s color and what system it goes to, so that was kind of a dead end for me. The one wire I did manage to figure out is found on connector i5, which connects to “F/B” (I think this means front wiring harness bulkhead wiring harness). Anyway, B2 is the wire on schematic WI-20 and goes to FB-27 (“Combination meter, Front fog light switch, Headlight leveling switch, Illumination light, Rear fog light switch”)
The FSM has neither the bulb for the clock backlight nor the odometer backlight, but the one I found at library shows both the bulbs.
All of the other dash lights work. When the turn signal is engaged there is a slight dimming of the indicator lights, like “brake” or the check engine light, and I’m not sure if this is normal. It doesn’t do this when just the hazards are on.
Recap of what tests/work I’ve done:
Replaced bulb. Swapped bulb. Swapped base (plastic twisty). Tested all bulbs when doing so. Checked combination meter grid for damage. Checked combination meter wires and connectors for damage. Checked continuity when bulb is in slot. Unplugged rear brake, turn, and rear backup light harnesses. Checked all chassis ground locations inside. Also, all engine grounds were cleaned (this is especially easy to do when the engine is out). All of this was done with no change and left no further clues.
Final thoughts:
Perhaps I am foolish to chase after an electric gremlin for something so petty. Perhaps I am overthinking this and the solution is much simpler than I think. Bottom line I don’t know how to navigate the schematics and I don’t know where I should be checking for continuity, ground etc. I think I have done all of the basics a layman can do. I have to figure out why my transmission buzzes in gear, why the rear defogger works only on a few lines, and why my mirror heaters aren’t turning on—although there are a good posts I have read and need to read on those issues before I post a question. This backlight issue is one that I can’t find any good posts on and I really could use your help. If you made it this far, thank you for reading.
The background:
When I became the owner, there were additional lights out in the cluster so I decided to replace ALL of the lights in the cluster. However, I noticed the clock backlight did not come on. So, I checked all pertinent fuses and pulled the bulb. Tested bulb. Bulb is good. Examined contacts on cluster. No visible damage. Checked continuity between various points on board and between contacts when bulb was twisted in and found no issues. Reinstalled and still no illumination
I kind of gave up at this point because, hey, it isn't the most serious of issues and the vehicle needed and work to make it seaworthy.
At some point in between this I am spinning around in the snow and the clock light illuminates (no idea if spinning in snow is relevant). Okay, so now it's taunting me. Eventually it goes back out one day, who knows how long it lasted, a few hundred miles maybe if that. Anyway, now I wanted to fix it even more, especially because it's annoying to look at a dash with a dark rectangle in it. So, I pulled up a wiring diagram from a library resource (I think it is Haynes) and became disheartened because it seemed tightly integrated into other working circuits that I didn’t know where to begin. I had to do the other work on the car so I gave up on this until recently finishing the major work. Right before I parked the light had randomly turned on again for a little bit. This was after I undid everything again (with my lacking of electrician’s skills I have to revert to a caveman style of simply unplugging and plugging things back in). I do all of this with the battery disconnected so I have no idea if it was simply another random occurrence.
Notable observations:
A previous owner or mechanic has tapped into a few wires and electric taped over the exposed wires. I tried for hours to teach myself how to understand Subaru’s FSM wiring schematics (power distribution, ground distribution, etc.) and I determined that there are only two wires that more or less directly go into the instrument cluster (it seems that every wire is connected in this vehicle, which makes sense if you think about it : ). One of them is found on SMJ i1 (of which I cannot find a FSM page that details each pole’s color and what system it goes to, so that was kind of a dead end for me. The one wire I did manage to figure out is found on connector i5, which connects to “F/B” (I think this means front wiring harness bulkhead wiring harness). Anyway, B2 is the wire on schematic WI-20 and goes to FB-27 (“Combination meter, Front fog light switch, Headlight leveling switch, Illumination light, Rear fog light switch”)
The FSM has neither the bulb for the clock backlight nor the odometer backlight, but the one I found at library shows both the bulbs.
All of the other dash lights work. When the turn signal is engaged there is a slight dimming of the indicator lights, like “brake” or the check engine light, and I’m not sure if this is normal. It doesn’t do this when just the hazards are on.
Recap of what tests/work I’ve done:
Replaced bulb. Swapped bulb. Swapped base (plastic twisty). Tested all bulbs when doing so. Checked combination meter grid for damage. Checked combination meter wires and connectors for damage. Checked continuity when bulb is in slot. Unplugged rear brake, turn, and rear backup light harnesses. Checked all chassis ground locations inside. Also, all engine grounds were cleaned (this is especially easy to do when the engine is out). All of this was done with no change and left no further clues.
Final thoughts:
Perhaps I am foolish to chase after an electric gremlin for something so petty. Perhaps I am overthinking this and the solution is much simpler than I think. Bottom line I don’t know how to navigate the schematics and I don’t know where I should be checking for continuity, ground etc. I think I have done all of the basics a layman can do. I have to figure out why my transmission buzzes in gear, why the rear defogger works only on a few lines, and why my mirror heaters aren’t turning on—although there are a good posts I have read and need to read on those issues before I post a question. This backlight issue is one that I can’t find any good posts on and I really could use your help. If you made it this far, thank you for reading.
Attachments
-
757.7 KB Views: 94
-
74.7 KB Views: 82
-
982.8 KB Views: 116