I picked up a pre-'73 GT cluster for my 145 on ebay. Owner said it worked fine when it was put in storage several years ago. I've connected it and while the odometer and tach work, the fuel and temp gauges do not.

I've already confirmed wiring to the cluster and sensors are good by hooking up my old cluster and getting readings on both gauges.

Diving into the GT cluster, I first thought it was the voltage regulator, so I replaced that with one known good, but it didn't help. I then started tracing the leads on the back board. The circuits from the connector to the gauge posts are all just fine, for both gauges.

So then I removed the gauges and measured for resistance directly across both leads, and both gauges show open circuit. I sanity checked and measured directly across the leads of the known good gauges and got resistance values around 50 ohms.

So I have to conclude that both gauges are somehow completely dead. Perhaps someone tested them both with 12V before I got the cluster and blew them both.

The real question is, can I get them repaired? I tried disassembling, but the front faces appear to be pressed on the body in a way that I might destroy the gauge getting it apart, but I know the internals have to come out the front. Is there any way I can get in there to repair them myself?