Hyundai Accent temperature

I have an Hyundai Accent 1995 1500 cc. The problem I present is that I recently repaired the full engine. Upon reaching normal temperature everything looks good, then the temperature begins to rise to more than 3/4 and then ignite the fans. I have noticed that when this happens, when lighting the lights the temperature rises a little more. I did the head of the head, the head of the head changed it for a laminate, the temperature, coland and pounding sensors are new. When I disconnect the battery positive the temperature stabilizes in the normal. Can you help me?