ac problem

I'm having trouble with the ac I took my car to get it charged with freeon and they told me that the ac switch was not sending a signal to the relay switch, they bypased the relay and the ac worked so they said that is going to cost around $120, SO I was wondering if some one had or has had the same problem

those guys are right, you have bad pressure swith.
their estimate is reasonable, switch cost only $30, but it will 1.5-2hrs of labor to do replace it. they have to pump freon out of system, replace switch and put freon back in, its not that hard to do but it takes time and time is money.

you run your AC with that switch by-passed and that is ok, but if your AC system developes leak, and pressure become to low, you might end up with seized AC compressor.
when mechanic charged AC system with freon he also added some oil, that oil is in system to lubricate compressor. so when pressure is low, freon doesn't move through out system as it should, compressor doesn't enough lubrication and that where that pressure switch comes into play, it detects low pressure and turns AC off to prevent compressor failure.
http://www.hondaautomotiveparts.com/catimgs/13SM40_E1601.gif
(http://www.hondaautomotiveparts.com/auto/jsp/mws/prddisplay.jsp?inputstate=5&catcgry1=Accord&catcgry2=1991&catcgry3=4DR+LX&catcgry4=KL5MT&catcgry5=A%2FC+++++HOSES-PIPES+%282%29)

on picture above you can find that switch in lower right corner under #32, and if click on picture it will open web site where you get ANY OEM parts for your car at warehouse price.