So I've got a 90 YJ, 6 cylinder. Wondering if anyone has ever messed with the heater and if it was a major headache? I haven't looked into what the issue might be under the hood yet but I'd imagine the element has gone out on it. Also the control panel on the dash probably needs to be replaced. The high-low works fine but the cool-heat and the other switch (fan-defrost?) aren't working. They both won't let you push them all the way to the right... So before I dive into this, is it something I could do on my own or should I take it to the shop? It's too darn cold not to get it fixed!