Just had gas put in the AC on my 91 350 SDL today. Works fine when moving 30 mph or more. Blows warm when stopped for a bit like the aux fan isn't coming on.
Questions are
Is the aux fan turned on by the AC relay or directly throught the high pressure switch? Also, where is the AC relay? Near the wipers?
Chris
First, remove the aux fan fuse and replace with new one. If this doesn't work, then you need to run power direct to aux fan to check if it is good. Once good, then you have to change the single and double prongs thermoswitch sensors on the engne... by the thermostat. If it still doesn't work, then check the high pressure switch by jumping the two wires together... you can do this test earlier too.
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