Faria gauges have a lifetime warranty. They will fix them like I said. Bad thing is the down time, but if they are not working now, then there really is no big loss on that. Call them and ask them about it, the volt gauge is a bit cheaper, but they quoated me 30 bucks to fix my tach out of a 1999 maxum 1900sr. Original gauge that came with the boat, looks real similar to the one in the pic, but mine are flushmounts. The one in the pics are the ones I ordered to replace my current set. I was going to send mine to them, but found the complete set at great lakes skipper for 299.00. The sizes were off just a bit so i am cutting some bigger holes in my dash so they will fit. I mainly bought the new set because mine are faded and the lenses scratched a bit,and I wanted to get some new ones that look factory.
Here is the link to the website. If you can pull the gauges out and get the part numbers off of them you can contact them and fillout a return. If you can't find the part number, them you can use the gauge finder on their website to locate it or go through maxumcustomercare and get the faria part number. Easiest way would be to call faria and give them the rundaown on your boat and gauge description. They can probably tell you for sure and get you set up with the warranty info. All the warranty info is on their site, along with the return forms etc..