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Rodgman15
01-07-2019, 10:05 AM
Got a good one for y'all.

97 A4BATQM

My instrument cluster took a shit, so I bought a used one (part for part swap). Installed it, everything worked great for a day or two, until last night when I parked it, turned my lights off, turned the ignition off, and the instrument cluster came back to life, fuel gauge, coolant temp gauge, and odometer would not turn off. Pulled fuses to no avail. Eventually found there must be a short of some sort in the headlight switch, found if I turned it off and on rapidly I could get the cluster to power down.

Clearly I'm looking for something in the column that's goofy, but does anyone know off hand if there's any direct correlation between the headlight switch and the instrument cluster? I've got the Bentley but haven't had time to trace the wiring schematics, so I thought I'd ask in case anyone else has come across this.

Anyone ever seen this before? Any info is appreciated, thanks!

Edit : just tried to get it to act up, cluster would not power down without pulling fuse #15, then jiggling the headlight switch killed it

PFAhttps://uploads.tapatalk-cdn.com/20190107/a98bbbe9caeebe812e11d51bd4048170.jpg

MetalMan
01-07-2019, 10:23 AM
Any non-off position of the headlight switch will illuminate the the cluster. Sounds like a replacement headlight switch is in your future?

Cybersombosis
01-07-2019, 11:02 AM
Take it apart and see what is up. Dust and dirt get into the switch contacts which cause shorts so all it may need is a good cleaning and lube with dielectric grease.

Doug

Rodgman15
01-07-2019, 12:33 PM
Any non-off position of the headlight switch will illuminate the the cluster. Sounds like a replacement headlight switch is in your future?Illumination is not the issue, constant cluster power is the issue, gauges still working after being turned off. Although I do believe the issue is in the headlight switch.

Rodgman15
01-07-2019, 01:17 PM
Take it apart and see what is up. Dust and dirt get into the switch contacts which cause shorts so all it may need is a good cleaning and lube with dielectric grease.

DougThat's plan of attack #1.

Weird thing is, it won't power down unless fuse 15 is pulled, headlight switch won't affect anything with it in. Pull it out, off and on a few times and clears up.

Still starting with the headlight switch.