Zooming993

Our heater in our 07 is starting to act up. The heater works but it's not consistent. When we’re driving it works fine but as soon as we come to a stop we loose heat, it blows but no heat While sitting at a stoplight you can actually feel the tempurature drop but as soon as press on the accelerator the tempurature rises. What could be the problem?

We have an aftermarket DVD system installed by the dealer when we bought our 07 GX. For some reason neither headrest DVD will power up. I checked all the fuses but I couldn't find any that were blown. Has anyone else experienced this problem?