SupraIV Gear Shift Indicator Failure

Whoa, that sounds like a major headache! I had something vaguely similar happen in my SupraIV, though not quite as dramatic. My gear shift indicator was acting wonky, flashing random gears, and sometimes wouldn't show anything at all. It felt like the car was guessing what gear it was in. Have you checked the wiring harness near the transmission? Sometimes those connectors can get corroded or loose.

Thanks for the suggestion. I did inspect the wiring harness and connectors, but found no obvious damage or corrosion. Could you elaborate on what component was ultimately faulty in your case?

Right, that's where it gets tricky. Unlike a lightbulb that just burns out, these things are usually more complicated. I ended up taking it to a workshop; it turned out to be a defective control unit. Apparently, it's a known issue, and a replacement was the only fix. Cost me around 1000€, but it solved the problem. I'd recommend getting it properly diagnosed to be sure, but it sure sounds like you are having a similar issue!

I appreciate the information regarding the control unit. I will take the vehicle to a qualified technician for diagnosis and repair, focusing on the affected control unit as the likely culprit. Thank you for your assistance.