I'm using 134a but by next weekend, I will have my sanden enhanced sd7 and parallel flow condenser bolted up. I have to wait for the mounting bracket to arrive and pull the last 2 hoses that don't come in the kit I'm ordering and drop them off at hosefast to be rebuilt. My a/c works now but as we all know as soon as it creeps over 80, the vent temps begin to rise with the outside temp. I have a large w126 aux fan on it now and when idling, it makes a huge difference when it is on. I was just curious if there was lower pressure or temperature switches that thread into the drier to trigger the fan? There is nothing wrong with my system now. I just wanted my fan triggered sooner.

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83 300CD- sanden, dual p/f condensers, 160a alternator, ect
91 300TD- 722.6, #22 head, 3.5L IP, w140 manifolds, ect