OBD2 port not communicating?

2000 AUDI TT
28,000 MILES • 1.8L • 4 CYL • TURBO • 2WD • MANUAL
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WFFWFF58
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Radio has no power. obd2 port not communicating. tried several different code readers including my mechanic's reader. tachometer and speedometer not working. heat gauge and fuel gauge fluctuate from lowest to highest reading available on the gauge, every second.
Nov 25, 2023 at 10:04 PM
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STRAILER
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There are two fuses (#7 and #12) that run the ALDL diagnostic connector we need to check. Here is a guide to help and the fuse locations in the images below:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Here are the ALDL connector wiring diagrams well. The fuses are in the left side of dash fuse panel.
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Nov 26, 2023 at 6:21 AM
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WFFWFF58
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Yeah, I was hoping that was the issue. I checked fuses 7, 12, and 42. All are good.
Nov 26, 2023 at 8:46 AM
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WFFWFF58
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Thank you so very much for reaching out!
Nov 26, 2023 at 8:49 AM
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STRAILER
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Okay, I would test the scanner on another car to make sure it works and if so, let's use this guide to help test the ground wire of the ALDL diagnostic connector (brown wires):

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Connect the test light to power and let me know.
Nov 27, 2023 at 1:09 AM
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WFFWFF58
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Hi Ken!
Traveling today for business. I will test the ground wires, pins 4 and 5 Tomorrow and then let you know what I find. Thanks again for your help!!!

William
Nov 27, 2023 at 7:55 AM
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STRAILER
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Sounds good, safe travels.
Nov 28, 2023 at 12:50 AM
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