sdquint Posted March 7, 2004 Share Posted March 7, 2004 We have a 98 Outback where the 10 amp instrument panel fuse keeps blowing. After no real diagnosis, we had the stalk (with the headlights, dimmer for panel, etc) replaced. This solved the problem for about a year, but about a month ago it returned. Now a new fuse will blow immediately when the headlights are turned on. Anyone with experience or ideas on this? Quote Link to comment Share on other sites More sharing options...
EOppegaard Posted March 7, 2004 Share Posted March 7, 2004 You have something shorting to ground somewhere, who replaced the panel? They should have made sure that all of the wiring is up to par at the same time. Does the problem only occur now when you turn on the headlights? These are the kind of things you need to trace in order to isolate the electrical problem. Quote Link to comment Share on other sites More sharing options...
CardinaA Posted March 7, 2004 Share Posted March 7, 2004 experienced problem with amateur install of a nackamichi cd player. the guy wired things screwey and i can't remember the exact fix, but it had something to do with wiring the dimmer into everything. have you had a new stereo put in recently, or is there anything messed with the radio? Quote Link to comment Share on other sites More sharing options...
sdquint Posted March 7, 2004 Author Share Posted March 7, 2004 Thanks for the ideas. We bought the car used and discovered the problem shortly after buying it. The previous owner admitted the problem had occurred maybe 1-2 times in the years they owned it (since new). I am not aware of any problems with the stereo nor of any new electronics added. One clue may be that when we took it to a dealer he told us that the car appeared to have had a repaired front end (not sure what) and that the windshield (that had the wiper heater in it originally) had been replaced with an aftermarket one without the heater. So, the connector for the heater must be dangling somewhere. I just went out to the car and removed the fuse for the wiper heater and, for the first time in a while, the illumination fuse did not immediately blow. BTW, it always seems to blow when the headlights are turned on, but I couldn't swear it doesn't happen other times (as, in the daylight the lights aren't on or the panel visibly lit). I am not aware of the panel ever being removed and replaced - it was the left-hand stalk that contains the light switch and dimmer that was replaced about a year ago and had "solved" the problem for a while. We'll see how long this fuse lasts! Quote Link to comment Share on other sites More sharing options...
sdquint Posted March 11, 2004 Author Share Posted March 11, 2004 This last fuse made it about 20 minutes with the headlights on. Sounds like its time for someone with some electrical trouble-shooting skills to take a crack at it. (Of course I've already paid about $200 for that about a year ago and told they couldn't find anything wrong. That fuse lasted about an hour.) How do you get someone in Subaru to help the dealer with this? Quote Link to comment Share on other sites More sharing options...
99obw Posted March 11, 2004 Share Posted March 11, 2004 It sounds to me as if your problem is NOT intermittent. I think that whatever short you have is always drawing too much current when the fuse is still intact. IIRC a typical slow-blow type fuse can take up to two hours to blow at it's rated current. It sounds like you know this but do not install a larger ampacity fuse. The easiest way to find the short is to divide and conquer. With the car's electrical diagram, find the circuits fed by the fuse that is blowing. Measure the current to each of the feeds at the fuseblock using a clamp-on ammeter capable of measuring DC. That should tell you where the problem lies. Then it's just a matter of working through the wiring diagram until the short or offending device is found. I hate to make it sound easy, but it really shouldn't be that hard. Many mechanics don't have any solid troubleshooting skills. They are simply parts changers. Maybe a good independent mechanic in your area could fix it if he had the wiring diagrams. Perhaps you could download the FSM from techinfo.subaru.com and supply it to the independent mechanic of your choice. Quote Link to comment Share on other sites More sharing options...
cookie Posted March 11, 2004 Share Posted March 11, 2004 Check this at night and you might find the culprit. This is how we found them on trucks and busses. Quote Link to comment Share on other sites More sharing options...
sdquint Posted March 11, 2004 Author Share Posted March 11, 2004 Thanks for the suggestions. Concerning dim lights, I am not aware of any - but there are a few burned out bulbs in the area of the heat and A/C buttons. Quote Link to comment Share on other sites More sharing options...
Tiny Clark Posted March 12, 2004 Share Posted March 12, 2004 When the fuse blows, what exactly do you lose? Do all the gauges go inop? Does anything else quit working? Is it just the instrument panel lights that go out? Maybe someone took the panel out at one time, and when they installed it, pinched the power wire against the surrounding metal. A big box of fuses is a lot cheaper that paying someone 80 bucks an hour to chase a problem like this. I've been chasing wiring problems on airplanes for 30 years, and your problem seems like it's going to be difficult to find. Quote Link to comment Share on other sites More sharing options...
sdquint Posted March 12, 2004 Author Share Posted March 12, 2004 The only lights that go out appear to be the ones that respond to the dimmer, eg speedo, tach, fuel, temp, gear indicators (down by the shifter), radio. Idiot lights, clock, all the interior lighting (dome, spots, doors, etc) continue to work. The problem with a whole box of fuses is that they blow either immediately or in a few minutes. BTW my short term solution has been to velcro one of those small LED head lamps in front of the main instruments so at least I can see my speed, fuel, temp, etc. What continues to puzzle me is why did replacing the stalk (with headlights, dimmer, etc) work for a year before the problem returned big time? Quote Link to comment Share on other sites More sharing options...
sdquint Posted March 12, 2004 Author Share Posted March 12, 2004 I didn't answer all of Tiny Clark's questions. The gauges and everything else continue to operate - it's just the illumination that goes out - a pitch-black instrument panel is quite unsettling. Quote Link to comment Share on other sites More sharing options...
Tiny Clark Posted March 12, 2004 Share Posted March 12, 2004 Don't know why it worked for a while after the stalk replacement. Maybe they moved it a bit when they took apart the steering wheel housing. Might be worth the effort to have the instrument panel removed and check the the wiring behind it. Read the wire that supplies that dimming light voltage to the panel with the fuse removed. It should be an open. Physically check that wire as well. Quote Link to comment Share on other sites More sharing options...
cookie Posted March 12, 2004 Share Posted March 12, 2004 on the spot and really tough over the internet. If it was my car I would go to an auto parts place and get a circuit breaker as constantly changing fuses while working on a car drives me nuts. Then I would hook up a trickle charger as when working on electricals a flat battery is common. Then I would remove each circuit powered by that system till I stopped setting off the circuit breaker. If it is not easy to disconnect a wire I just cut it and solder it back and shrink wrap it when I am done. I have also had to disconnect circuits and drive down a bumpy road to find a problem like this. If it was a BMW it would most likely be the lighted shift knob wire as the shifter moves constantly and tends to short that wire. On a Subaru you got me. Dimmer switch stalks are another common problem and if this unplugs try that. I have plugged in a replacement and driven with it loose to test also. Quote Link to comment Share on other sites More sharing options...
99obw Posted March 12, 2004 Share Posted March 12, 2004 The problem with removing one ciruit at a time is that you may remove a circuit that is perfectly fine but is causing the current draw to be beyond what the fuse can handle, then the fuse will stop blowing but the problem still exists. An inconclusive experiment. That is why I recommend actually measuring the current into each circuit. Quote Link to comment Share on other sites More sharing options...
cookie Posted March 12, 2004 Share Posted March 12, 2004 knowledge of electronics. This would work better than the way I do it if you have bit more skill. So far I have gotten by muddling through the way I was taught but there are always better ways. Quote Link to comment Share on other sites More sharing options...
Tiny Clark Posted March 12, 2004 Share Posted March 12, 2004 I’m looking at my dimmer wiring diagram for my ’96 Legacy. It shows the following connected to it: Fog light sw TCS sw Hazard sw Cruise Cont sw Defogger sw Glove Box Ash Tray CD and Radio Combination Meter (Inst Panel) You may have more It could be that any one of the wires going to these things is pinched somewhere. It wouldn’t cost you anything to start looking around in these areas. It also could be the lighting control module itself. I would guess it is one of the many boxes located under the lower panel on the dash below the steering column. There are quite a few things attached to that, and I don’t know what all of them do. The light-dimming system must be controlled by some sort of solid-state FM (frikkin’ magic) circuitry in that module. The dial on your light stick just varies the resistance to that circuit. What happens if you turn the lights as low as possible, or off? This would draw less current out of the box, and should keep the fuse from blowing (Maybe). If it still blows, my money is on the module itself, or the wires going to it. Oh yea, exactly what fuse blows, No. 9? Quote Link to comment Share on other sites More sharing options...
sdquint Posted March 13, 2004 Author Share Posted March 13, 2004 Thanks for all the info and suggestions. Fuse is #9. I believe the fuse has blown when the dimmer is at about half and possibly even when it is completely off (with the headlights on). The Subaru dealer (in Montrose, CO) said they would talk to the zone rep - my hope is that they would contribute some time, not on my dime, if it turns out to be a MANY hour research project. I know it could be some obscure wire, because I have an SVX that had some major electrical gremlin (don't recall exactly what - it was many years ago) caused by a short in the wire that goes to the light in the sun visor. The mechanic at the dealer did seem knowledgable and experienced in these problems - he also suggested putting in a circuit breaker. Quote Link to comment Share on other sites More sharing options...
Tiny Clark Posted March 13, 2004 Share Posted March 13, 2004 Don't rule out the dimmer module. Try to find one at a junk yard. Quote Link to comment Share on other sites More sharing options...
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