I have an older sears window unit, we cleaned it thorughly clean filter, coil etc but it is still iceing up on the inside. What is causing this to happen?

May be low on refrigerant. The fan is running a proper speed, isn't it?

I have an older sears window unit, we cleaned it thorughly clean filter, coil ect but it is still iceing up on the inside. what is causing this to happen?
I work for Traine. And sounds to me like either the Thermostat is broken and isn't letting the compressor shut off or a lot of moisture is getting in the unit which could be do to the water drain being clogged up. Check the drain pan and see if any water is collecting in it. Will have to look in the unit to do this but I'm sure it's one of the 2.

If it's an older window unit, my guess is that it's low on freon. My advice is to pull it out and take it in to a local heating and air company, they can find the leak and recharge it for you if this is the problem, and it would be much cheaper than calling them out. If this isn't the problem, they can quickly diagnose the problem. Sometimes it's cheaper just to replace it.