2010 international prostar problems

I'm having a similair problem with my 96 kw. When i crank up my truck the fan is off but if i turn on my ac the fan comes on even with the engine temp still cool.This is a 3406e caterpillar engine.The manaul fan switch is off.Any help would be helpful.
Thanks,
James

 

that is normal--as long as it goes off in awhile--it is just cycling when ac is on

 

The hot gases that leave the compressor must be cooled and condensed across the condenser at the front of your rad. Without air flow across it the pressure will keep rising until something lets go. The fan will kick in to cool the pressurized refrigerant and condense it into a liquid so it can make cold air later in the system. Your fan will come on too when you have defrost selected. The a/c runs in defrost mode because the a/c removes moisture from the air to help clear the windshield.

 

thanx heavy---that is a good way of explaining it--i was trying to but it wasnt coming out right--

 

You fan will come on for the AC high preasure switch, engine coolant, engine oil tempature, manually from the switch, and intake air tempature.
Just a thought!

 

during the winter months ,I take the fuse out for the a/c/ compressor, so I can use the defroster & not cost me more in fuel by the compressor running. sometimes you have to keep the defroster on for hours going down the road in certain conditions.

 

Thanks,for all the quick helps but i think something is wrong because when i just crank the truck the fan is off but the second i turn my ac on it comes on and continues to come on and off very rapidly as to where it did not do this prior to starting my truck. if i turn off my truck with ac on and start it up again after a cool down period the fan comes on instantly and goes off for a minute or so then comes back on. Ive read somewhere if the fan works in a consistant manner it will damage the clutch. I had the fan clutch replaced about 9 months ago because of the squealing it was doing and everything seemed to be fine then- but when i recharged my ac it is doing this on/off method.wandering if it has anything to do with that or some kind of switch.

 

Sounds like the A/C is overcharged, and the high limit switch is kicking the fan on to try to bring down the head pressure. Is the fan cycling exactly with the A/C, or out of sequence? If on and off exactly at the same time, the cycling switch may be bad.

 

I am running a 2011 International Prostar 18 speed automatic and I'm just wondering if anyone else has a problem with the diff locks only locking at 30 kph or under and kicking out at 40 kph and is there a way to make them lock in at any speed.

 

I use to pull a/c presure switch connector.

BTW on newer trucks when A/c clutch is on and speed is over 30 mph and temperature of ccolant is lower 160 fan clutch is not actuated.

There are two speed fan clutches on some trucks and when A/c is on low fan speed is used. It saves fuel too.