Bo, I had all the front fairing off to do the speedometer mod, and while I was at it I also hosed off the dirt and bugs. Probably shouldn't have, but everything was very dusty and buggy from my recent trip to Alaska.
After getting everything back together one of the instrument panel fuses had blown (#1 or #5 - can't remember which). I replaced that and now everything works but the instrument panel lights.
The onboard computer is working, including the light. I check the bulbs and they are OK.
Is the next step pulling the gas tank and checking the connector at the electrical box? Can't imagine why that would be the problem. On the other hand, there was a short some place that resulted in the blown fuse (#5 or #1) after I had it back together. I also found that the insulation on the wires to one of the panel lights was bad and had been taped at some point. I re-repaired that with new tape. Could a short in the circut to one of the lights result in damage to the wiring harness further down the line?
No don't pull the gas tank just yet. Looking at the schematic for 2001-on instrument panels (and keep in mind that schematics always confuse me), it looks like there are two wiring harnesses/connectors to the panel. (I'm going to try to think this through in this post, so bear with me and check my reasoning.) One of the connectors has the circuits for the LCD/gear selector readout, coolant temp gauge, tach, speedo, and fuel gauge. The other has the circuits for the panel lights, including cruise indicator light, neutral, reverse, ABS, fuel warning light, oil light, low battery charge condition, high coolant temp, high beam, and right and left turn signals. So the first group is working, the second it not. There are only two overlaps that I see between the two wiring harness. One is that the lights that illuminate the speedo (you only see them on at night) use the same ground path as the high beam indicator light, and right and left turn signal indicator lights. So, fire up the beast, throw a blanket or something over the instrument panel and your head, and see if the speedo lights are on or off. Hit the left and right turn signal levers and see if their corresponding instrument panel indicator lights flash. Turn on the high beam and see if the corresponding indicator light comes on.
Condition: speedo lights come on, panel lights for turn signals and hi beam do not come on.
Conclusion: ground path for instrument cluster lights is OK at least through the connector.
Condition: speedo lights do NOT come on, panel lights for turn signals and hi beam do not come on.
Conclusion: ground path for instrument cluster lights is cut/shorted. It cannot be on the positive side of the curcuit because each of the "test" lights gets it power via different paths.
If there is no good ground path it seems likely that the problem is a loose connection at the connector or in the path back from the connector to the battery ground. If the speedo lights come on I'm not sure what the issue is. It's not the fuse, since the LCD and gauges work. Any other ideas out there?
Bill, the panel lights are the *only* things not working - all of the other lights and guages you mention in relation to the 2 harnesses work properly.
I believe the panel lights for the 2001 LT are on all the time - day and night. In any case, I've checked at night and there are no panel lights.
My plan is to pull the gas tank tonight or early next week to check the connectors at the electrical box, and to confirm that 12v is making it to the box. I don't see any other possible cause of the panel lights not working at this point, but I'd be happy to be proven wrong...
I found the problem. I pulled the gas tank this evening and the insulation on the two wires feeding the panel lights was fried right at the connector to the main wiring harness. The hot wire was broken. I'm hoping this is the only problem...
I'll do the repair over the weekend or early next week and post the outcome.
I repaired the broken and over-heated sections of wiring this evening, put everything back together just like I found it and, ta da, it works! Now I just hope the repair will hold up over the long run...
Yes, solder and shrink wrap - both the hot wire and the ground wire for the panel lights. Fortunately there was enough wire still protruding from the plug that I could just solder on more wire. I also splice in enough additional wire so that there wouldn't be any stress due to pulling on the wires - I think perhaps that was the problem with the hot wire.
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