Toyota heated seats do not work consistently?

I have a 2005 Toyota Solara with 27,000 miles. The heated seats only come on for about 1 minute every 10 minutes. They also do not begin to heat until hot air starts to blow from the heater. I have tested 3 other Toyotas and they all started to heat within 20 seconds and all heated for 2 minutes every 2 minutes, or as soon as they started to cool, they began to heat again. Also, the battery was just replaced because it tested marginal. Could there be a loose wire somewhere? Is there any source that could affect both the battery and the heated seats? I don't understand why my seats do not work as well as the other Toyotas I tried.