87 B2200 AC trouble

My ac seems to work when I get into my truck when it is a very hot day but on the medium warm days it will not work for nothing is there a temperature relay any help would be appreciated.:screwy:

The temp control for the a/c is located on the dash panel where the mix contol is.If it works when real hot should work when a little hot outside unless the temp contrast is greater and u just think it is working better when real hot outside.If not cold enough,have system serviced and charged up IF u can find someone with Freon and ur system has not been changed over to R-234.BJ

I've gone through a few fan clutches on my B2200, they seem to last 6 years only for me (Arizona). Buy good quality, or Hayden lifetime from Pep Boys like I did.