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Andy, Technician
Category: Heavy Equipment
Satisfied Customers: 1647
Experience:  310s and 310t technician licenses, 17 yrs experience, International Diamond Certified Tech 7 yrs
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Have a 2000 Kenworth W900L. Engine fan will not shut off. Engine

Customer Question

Have a 2000 Kenworth W900L. Engine fan will not shut off. Engine temp is at about 180
Submitted: 7 years ago.
Category: Heavy Equipment
Expert:  Andy replied 7 years ago.

Hi there, I may be able to help you! I believe that there is a two wire electric solenoid mounted on the firewall above the engine closer to the heater housing. you should start by checking that there is air getting to solenoid. The air pressure is what releases the fan clutch and lets the fan freewheel. If there is ample air pressure getting to it, you may want to check to see at the 2-wire connector , if there is 12 volts at the connector. When you do so, please make sure that the heater inside is set to floor and hot. This assures that ac is not running causing fan to stay on . If you do get 12 volts at the harness side of connector, then you may want to check for resistance on solenoid connector. You should have about 12 to 24 ohms or so. It should not read OL. If it does, then solenoid is defective and needs to be replaced. The circuit is designed this way to default to continuous fan so that engine does not overheat and leave you stuck somewhere. I hope this helps you? Pleas click on accept if this resolves your issue and feedback would be much appreciated. Thanks again for using JUST ANSWER! Don't hesitate if you need more help!

Edited by Andy3221 on 2/17/2010 at 1:56 AM EST
Expert:  Andy replied 7 years ago.

Also, your ac high pressure switch may be causing fan to stay on as well. You can test that by unplugging it. Thanks again

Customer: replied 7 years ago.
OK. I'll try to check this out later. It's dark and cold, so give me a little time to work on this. Thanks
Expert:  Andy replied 7 years ago.

Ok! Let me know if you need anything else.

Customer: replied 7 years ago.
Tryed what you said. Everything seems to be fine with the solenoid and the fan switch. I did notice the belts became very loose. So I readjusted and seems to be working fine. Now I just have to figure how and why the belt pulley came loose. Thank you anyway.