Auto Air Conditioning & Heater Repair: Ford F150 1994 Air Conditioning, c lines, ford f150

Question
Hi,
Our air conditioning unit is having some problems.  It seems to work for a short while and then stops working and just blows out hot air from outside.  If I switch the air con off for a while say 2-5 mins and then turn it back on it works again for a while but will then stop again.
Any ideas?
Thanks.

Answer
When it starts to blow warm air is the A/C compressor OFF or ON ?.

Your most likely problems. PROVIDED that NO WORK has been performed on the A/C system are:

Low freon.
restricted orfice tube (expansion valve).
Compressor NOT cycling ON and OFF

Look to see if you are getting a heavy frost or iCE build up on ANY of the A/C lines under the hood.

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