welcome to the garage Dave, you'll find help sorting out the problem here ... the needle to the left means as it would be with the key off? first check the wire from the gauge to the sender with an ohmeter, could even be the wire broke at the sender terminal - if that's good, check the resistance of the sender [terminal to ground, cold vs hot should be different] if that all checks out you'll be needing to make a post in the parts wanted for a replacement gauge ... I'd think most likely would be the sender, available at NAPA or such
Bill