Overheating when the AC is turned off.

[Jadenjdawg]

Need some advice. I was recently driving down the road and noticed my temperature guage was rising and almost to Hot. I immediately pulled over to the side of the road, and switched on the AC to high. After doing this, the engine temperature went back down to normal, where it always runs. 4.0 with automatic transmission. The radiator and coolant was replaced last summer.

 

[Twister]

Need some advice. I was recently driving down the road and noticed my temperature guage was rising and almost to Hot. I immediately pulled over to the side of the road, and switched on the AC to high. After doing this, the engine temperature went back down to normal, where it always runs. 4.0 with automatic transmission. The radiator and coolant was replaced last summer.

Did you turn the AC on or the heat? Why would you turn the AC on when you truck is running hot?

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[Jadenjdawg]

I turned the AC on. I was in traffic and was trying to get over and was attempting to switch it to heat, but when I switched it on it immediately dropped the temperature. Strange but true. I turned the AC off about ten minutes later and drove another couple of miles and it stayed at normal temperature?

 

[Frank The Tank]

I've heard of that happening once before... The wiring was crossed and the electric radiator fans were tied into the AC.

Otherwise that makes zero sense and should have made the situation much worse.