I recently replaced the temp sensor switch on my 1989 300 SEL due to the a/c cutting off. Stupid me I lost all the refrigerant, at any rate I thought for a while the problem was fixed but yet again the a/c cut off while driving. Outside air seems to always be 89 plus when this occurs. Also, if I stop the car and restart, 9 times out of 10 the a/c will resume blowing cold air. Any suggestions and should I not have converted to 134r ?