Please post pics. I'm sorry about your tree.

Soap does not work on scale. You will need a hort oil.

Tim Walker is correct. Actually scale is quite easy to control/eradicate when you use Horticultural oil. Many times eradication is accomplished with the first spray, if the upper and lower leaf surfaces and the wood portions of the tree are thoroughly covered.

The third picture is what it looked like 1-2 months ago. I recently tried the hort oil a week ago. There are just no leaves left on the tree though. How can I get it it to grow leaves/branches or make sure it survives?

Thank you

In the middle picture showing the pot and your blue automatic watering device, the tree is showing trifolate (root stock) - the three leave shoot on the bottom left. You should pinch any three leaf clusters off. Scale wouldn't normally cause massive drop unless the case was extreme, which doesn't sound like it.

I wouldn't use an automatic watering device. But if that is the location you keep the tree at, then I would hazzard the "warm house" is the cause. The vent showing looks like it may be blowing, so the hot dry - desert winds from your vent may be the cause in conjunction with the other environmental changes (light and temperature).

Thank you Fruity Paws

The leaves were dropping even before it was by the vent. (The watering devices are always empty, just for decoration right now). I am truly stumped.

This might be helpful: http://www.steffenreichel.homepage.t-online.de/Citrus/lime2.pdf

Thank you

I see what Fruity Paw and Vladimir are saying. I will try to keep my plant "cooler".

I really need help.

Anymore advice? My tree now has no leaves and the top of the tree is dying. Is it too late?

Probably is too late but I still have a little hope.

Did you resolve your scale issue? Any updated pictures? I know you say the top is dying back. Is it turning black? Or just drying up brown?

Is the cambium still alive on the scion (not the root stock - trifolate) - you can scrape lightly on the bark and if it's green it's still alive. If it is alive, you are not without hope.

Well if it were my tree............I would lift that shade up to bare window, and let more light filter in and I would do a re pot 911 asap! That soil mix looks like it's killing the roots and I would not let another day go by in that stuff..Once those roots start to breathe and a much better aerated mix, you might see improvement immediately..That tree is very week, struggling, therefor the saps on that tree are very inviting for scale and other pests..

I would also keep close watch that the scale and mites do not come back while it's trying to recover)