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C. Walker, Jr.
C. Walker, Jr., Auto Mechanic
Category: Volvo
Satisfied Customers: 711
Experience:  Shop training and experience.
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Have a xc90 2013 the cooling fan will not operate. Went to

Customer Question

Have a xc90 2013 the cooling fan will not operate. Went to dealer said to replace the cooling fan code P048000. I replaced fan and its still not working comes on for a couple of seconds at start up then stops. The voltage on the messenger wire at start up is 2.5 volts then after couple of seconds drops to 1.5 volts then to .8 volts. The car is hot enough the fan should be running and I have the a/c on high. Car has overheated twice because fan is not coming on. The first fan would come on after the car would set for a day or so then after car ran for awhile fan would shut down.
Submitted: 2 years ago.
Category: Volvo
Expert:  Jon D replied 2 years ago.

Have you tried replacing the fan relay? Most of the time they use a lot of the same relays for different things. You could try swapping the fan relay with one that you know is good, i.e. on a system that you know is working. If that fan works then whatever you removed the other relay from doesn't, you know its bad.

Customer: replied 2 years ago.
the relay is actually on the fan unit itself so when I changed the fan it came with a new relay.
Expert:  Jon D replied 2 years ago.

You are right. Looking at the assembly everything comes on it. It could be a possibility of a new bad assembly, but I don't have access to volvo stuff to help you diagnose the electric issues here. I am going to opt out, and someone else will be by to help you. No need to post a response, it will just lock me back into the question.

Expert:  CHEVYEATER351 replied 2 years ago.

Hello there are a few checks that you can do. 1. Check the fuse for the cooling fan and make sure that the old fan did not blow the fuse. 2 You can check the power and ground at the fan to make sure you have a good power and ground. The other wiring goes to the control unit to control the speed so make sure to stay away from the small wiring. I have a feeling the fuse may be your issue.

Customer: replied 2 years ago.
All fuses check out have power to fan. The control wire that operates the relay on the fan loses all power seconds after start up.
Expert:  CHEVYEATER351 replied 2 years ago.

I am going to open this question up, this is going to need a more in depth solution as you have checked all the basics, I am going to opt out, you do not need to reply this will lock the question back to me.

Expert:  C. Walker, Jr. replied 2 years ago.

The signal that your losing is coming from the ECM. Since you replaced the cooling fan module already I would replace the ECM. Let me know if you have any questions. Thanks.