RedimprezaOB

Ok. After way too much fooling around with this.........i.e., hooking up monitoring lEDs on circuits and then eliminating each circuit yada, yada, yada. Dang. So, the switched and dimmable illumination circuit comes in on a violet wire. Works great no issues. Just because the LCD backlight is a 'light', the circuit was in question. Removed that circuit / wire from the plug at the radio and still had the problem. Over time removed all wires except for the constant 12v supply for the memory (think mine was a Blue w/ Red stripe) and the ground wire. Turns out the constant 12v supply comes in from a circuit off the Interior Illumination circuit. Thus, when the Interior illumination fuse is removed under the hood the LCD backlight turned off. Long story short, issue is internal to the radio itself. Good grief. All that to know the issue was the radio!

Yes. I waffle on the fence by the hour. It's the radio head. It's something else. Seems to now have gone intermittent so I'll work with it a bit more and report back if I find anything new and of course the outcome. Thanks for the ideas so far.

Well, had some time to think about it a little more and do some testing the meter as well. Meter shows the illumination circuit is of (0 V) when the key is, and wiggled a bit. It only comes on when the key is in run position and lights are on. All other dash lights operate normally. Interestingly, radio properly plugged in or disconnected, when key is in the run position with the lights on, the clock looks normal. Flip on the parking lights at this point and the clock gets "flashy" - perhaps like a fluorescent having a problem turning on might be a good description. So, disconnection of the radio just eliminates the drain through the LCD. There is still some issue. This one might be beyond me. Wouldn't think it would be the illumination module as the other dash lights operate properly. I don't have a great schematic but many of the dash lights appear to be on the same circuit. Better sit down with the shop cat discuss this over libations.....

See where our minds go?! I was just thinking of that and looking at where I would add (the connections) a transistor that would accomplish the task. Hand free and thoughtless operation.

Funny the question about the CD! When I was working on it in the garage (nice and quite) and connected the power again I heard the CD cycle. I thought to myself, this better not be the case. But, it wasn't. Whew!! Don't get me wrong, it would have been nice to have resolved at that point. So, yes. Pulled the radio and then removed the illumination pin from the circuit and reassembled. No, current draw. I'm concluding that the issue is in the radio head itself. Now, to find something nobody will want to break into it for when I leave it and am out on bike.... or as suggested maybe I don't need a backlight tuner screen most of the time Thanks for the ideas. This car has been an absolute electrical pill pretty much since 30k miles. Guess we need something to challenge us!

Thanks for that insight. The glove box was the only thing that really was causing me (and the cat) to think something outside the radio might be amiss. However, with key on / lights on it works. The actual radio illumination lights work as they should with the light and dimmer circuit. Just the LDC backlight that never turns off. Thanks again.

I'm trying to run down an odd electrical issue on my 2004, impreza ob. This popped up several weeks back just before vacation so removing a fuse to keep the battery from draining has been the solution until I had time to look at it. (Searched past discussions but didn't locate this issue) Symptom: The LCD 'backlight/illumination' never turns off on the OEM (never touched) radio. Pulling the radio fuse (fuse 9 under the dash I think) does not turn it off. Removing the Illumination fuse (12 under the dash as I recall) does not shut it off. In fact, I removal of any single fuse under the dash had no effect. I have to remove the "interior illumination' fuse under the hood to shut it off. Also the glove box light does not come on - bulb tested and good. I'll test the glove box switch short.....ly. Schematics don't show but recalling how the LCD backlight performed prior to this issue I would assume it is powered by the interior illumination circuit and the issue may be internal to the radio so a replacement may be the fix. But that doesn't explain the glove box issue which occurred at the same time. I'd hate to throw down on a replacement stereo and still have the problem..... Any thoughts, similar experience, better schematics? The shop cat has been no help on this one choosing to nap on the manual instead of providing any real insight.

I probably shouldn't say amything because I own a 2005. But, I was at my sending units last year at this time. In this newer car the closer to 0 ohms the closer to full the reading and 90 to 95 Ohms was empty. ...rrrr the other way round. Point being a Megaohm seems really high. 50 ohms put me at a perfect half tank.

Man am I glad I'm not the only one this has happened too! You can bet the booger was #3. I did what GD discibed, a pair or 40'ish degree needle nose did the job. Hope your back feels better.

Well it sounds like you know what is not causing the problem now! From what you have written, this is sounding like an electric issue. Grab those schematics and find the coolant temp circuit in.....engine electrical I think. At least that is where it is for the 04. I would trace the circuit in the car from the meter assembly to the sensor. Probably a short to ground. The temp sensor is a variable resistor so you could get a reading off your old one or disconnect and measure the new one then work through the circuit to see if the meter is getting the same reading you got at the sensor. Also I think the ECU monitors this circuit, again it does on mine but you'll have to check your diagrams. If so, you should unplug that connector from the ECU so don't get funny readings. Good luck. I finally ran down my electrical gremlin in the meter assembly PCB. I suspect though that is rare and an abraided / rodent chewed wire is usually the culprit.

I can surely attest to DEET being able to soften and make plastics / rubber very sticky!

Doh, must have read the pricing incorrectly. For 40 more I get the fuel temp gauge assembly and no messing around. Part will get here late this week. Thanks