AC problem

usually the engine cooling fan comes on automatically when the a/c is turned on.

 

What truck is this on? Pete's their is a high pressure switch that kicks the fan on only if pressures get so high. Also your confessor and rad could be full of dirt to a point where the air flow is not enough for heat exchange... wash it out. What are pressures thru ac gauges could be something as simple as low freon level. Gauges would tell you that. Just some point to start

 

Your fan should cycle when the A/C is on. It's getting warm when you stop because the high pressure cutout switch is shutting the compressor off when the fan didn't come on and the pressure got too high.

 

That’s right, and my guess is You don’t have a fan manual fAn switch.The switch that activates the fan is probably bad. Typically when the a/c pressure gets too high. High pressure switch cycles compressor off, and fan switch turns fan on, until pressure drops to normal. The fan switch may be separate or in combination with the high pressure switch,known as a bianary switch. In the case of a bianary switch, both actions are controlled by same switch, for instance, compressor off and fan on. One or both sides of a bianary switch could be bad. Either way, Find out which switch turns fan on, and replace it.

 

Then the switch is likely combined with another in a binary or trinary switch. I let my account on Freightliner lapse so I can't get wiring diagrams anymore.

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