Instruct: Classify Amazon reviews into positive or negative sentiment
Query: check the battery!

At first this speedometer worked poorly, if at all -- the display showed that it only occasionally connected with the sending unit, so all results were bad. I had tried repositioning both parts exactly per the instructions, but nothing worked. I was about to send it back, but called tech support. "Randy" told me to check the battery in the sending unit. They evidently had a bad batch of Mitsubishi batteries, and that is what I found. When I replaced it with a new battery, everything worked fine.Now I find it easy to use, easy to read, and reliable.