Volunteer 875 diesel cooling fan does not work

[Chris B Legge]

I have checked that the fan operates if you bypass it, I have checked the fuses, I have checked the relays but the fan does not come on and overheats. Has anyone had this experience. HELP!!

 

Chris Legge

[kenfain]

Have you tested the sending unit? 

[Chris B Legge]

Yes I by passed the sending unit and still no operating fan

[kenfain]

Have you put tested the fan itself?

[Chris B Legge]

Yes I by passed the fan and it worked well

[kenfain]

The sending unit would be my best guess. And its the easiest fix, also its probably the most common. It's a simple heat operated switch. So before replacing it, I'd test it for proper operation. Not a simple bypass, but an actual test. Check it for continuity across the two terminals before you start the motor. Get the motor up to temperature, then test it for continuity again. If it reads the same zero continuity, then I'd replace the sending unit. 

[Chris B Legge]

Thank you very much, I will test as you suggested