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How To Clean The Battery Cooling Fan in A 2004-2009 Toyota Prius

Updated on October 13, 2013

Toyota Prius Battery Fan Cleaning

Second Generation Toyota Prius, 2008 Model Year
Second Generation Toyota Prius, 2008 Model Year | Source

Why Clean The Battery Fan?

The battery cooling fan does its job hidden away behind the interior trim panels in the rear cargo space of the Prius. Toyota doesn't require or suggest cleaning this fan as a part of a regular maintenance schedule and most people won't ever need to. However, if you regularly carry furry friends in the back seat, you might want to do so every 60,000 miles or sooner. The battery fan intake vent in the rear-right of the Prius can suck in loose hair and debris, clogging the fins inside the blower fan that feeds cabin air into the battery pack to keep it cool.

If allowed to accumulate over time, eventually the fan can be completely clogged with fur and dirt, preventing the fan from doing its job of keeping the battery cool. This can cause error codes related to the battery pack overheating, reduced performance as the car's multiple ECU's (Electronic Control Units) limit the usage of the battery for driving or for regenerative braking and it can also lead to premature failure of the high voltage battery pack due to bieng subjected to extreme temperatures.

Picture Guide to Accessing Prius Battery Fan

Remove the bottom seat cushion in the back, it is held in place by two of these loops, one on each side and pull out easily.
Remove the bottom seat cushion in the back, it is held in place by two of these loops, one on each side and pull out easily. | Source
Remove this bolt using a 12 mm socket.  Then pull out the intake grill assembly.
Remove this bolt using a 12 mm socket. Then pull out the intake grill assembly. | Source
Fold seats down.
Fold seats down. | Source
Remove this bolt using a 10 mm socket and extender.
Remove this bolt using a 10 mm socket and extender. | Source
Remove this bolt with a 10 mm socket.
Remove this bolt with a 10 mm socket. | Source
Remove this bolt and luggage strap hook point with a 10 mm socket.
Remove this bolt and luggage strap hook point with a 10 mm socket. | Source
Remove this part of the hatch trim, it pulls out easily with both hands and pops out.
Remove this part of the hatch trim, it pulls out easily with both hands and pops out. | Source
Pull the right rear trim out, it is held in place with upholstery push pins.
Pull the right rear trim out, it is held in place with upholstery push pins. | Source
Remove bolt and luggage hook point with 10 mm socket.
Remove bolt and luggage hook point with 10 mm socket. | Source
Same as the other one on the left.
Same as the other one on the left. | Source
Pull up the carpet panel over the battery.
Pull up the carpet panel over the battery. | Source
Remove upholstery push pin and pull out right-rear interior panel.
Remove upholstery push pin and pull out right-rear interior panel. | Source
The battery cooling fan and duct assembly.
The battery cooling fan and duct assembly. | Source
10 mm socket.
10 mm socket. | Source
10 mm socket.
10 mm socket. | Source
Gently pull on the ducting assembly to pop out this push pin and remove the intake duct to gain access to the third bolt holding the fan on.
Gently pull on the ducting assembly to pop out this push pin and remove the intake duct to gain access to the third bolt holding the fan on. | Source
10 mm socket.
10 mm socket. | Source
Remove plug (don't disconnect) by squeezing clips on opposite (hidden in picture) side and pushing down.
Remove plug (don't disconnect) by squeezing clips on opposite (hidden in picture) side and pushing down. | Source
Remove fan power plug by squeezing clip on the plug and pulling out gently.
Remove fan power plug by squeezing clip on the plug and pulling out gently. | Source
The battery fan removed and disconnected.
The battery fan removed and disconnected. | Source
A deeper look inside the cooling fan, some buildup of dirt on the fins but nothing that will prevent it from doing its job.
A deeper look inside the cooling fan, some buildup of dirt on the fins but nothing that will prevent it from doing its job. | Source

Tools Needed To Get To The Battery Cooling Fan In A Prius

In order to remove the interior pieces and components in the way of the cooling fan, you will at least need:

- 1 x 10 mm socket

- 1 x 12 mm socket

- 1 x pair of good hands

I also recommend an upholstery pin removal tool that slides under the head of the push pin and allows you to pop it out much more easily than trying to pull on the material around it.

Step By Step Directions To Remove The Battery Cooling Fan

1. Remove the rear back set cushion, it is held in place by two steel loops, one on each side and remove easily by lifting up with a steady pull.

2. Remove the bolt holding on the fan intake cover using a 12 mm socket.

3. Fold the seats down.

4. Remove hatch area carpet/mat and spare tire cover and cargo tray in the rear.

5. Remove the recessed bolt near the right rear seat belt using a 10 mm socket and extension and then remove the 10 mm bolt at the very rear of the vehicle on the right rear trim panel.

6. Remove the bolt and luggage tie down hook with a 10 mm socket.

7. Remove the bolts and luggage tie down hooks on the left and right rear on top of the battery pack.

8. Lift up and flip back the carpet pad cover over the battery pack.

9. Remove upholstery pin holding right rear trim panel on cooling exhaust duct.

10. Remove rear hatch trim piece covering the hatch locking mechanism (see photo) by gripping with both hands and lifting out.

11. Pop out both upholstery pins holding right rear trim panel (see photo).

12. Remove right rear trim panel.

13. Gently pull on the intake duct near the push pin holding it to the right side of the vehicle.

14. Remove push pin holding other end of intake duct to battery cooling fan (highly recommended to use an upholstery pin removal tool).

15. Remove intake duct.

16. Remove all three 10 mm bolts holding cooling fan on.

17. Remove the fan control plug by squeezing the clips on the side opposite of where the plug is mounted to and pushing them through (see photo).

18. Remove battery cooling fan power plug by squeezing the tab and gently pulling it out of the socket.


Re-installation is the reverse of removal.

Cleaning The Cooling Fan

If the fan is has hair or lint in it, try using a vacuum cleaner with a crevice tool to suck it out. For finer, stickier grime that won't vacuum off easily, use an old toothbrush or pipe cleaner to loosen and then vacuum it out.

When re-assembling, make sure you get the power plug for the fan reconnected before bolting everything back in or else your Prius will throw a diagnostic trouble code relating to the battery cooling fan not working (well duh) and you'll also have the master warning triangle lit up on the dash. This won't harm your Prius, its just letting you know something isn't right. The code can be cleared by disconnected the negative terminal on the 12 volt battery in the rear for a few seconds and reconnecting. Keep in mind that if you need to do this, you'll lose any radio presets as well as mileage driven and average mpg information and will have to re-initialize the auto roll down feature on the driver window by holding the control button down until the window is fully down and then holding it up until the window is all the way up before the auto feature will work again.

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    • jesimpki profile image
      Author

      jesimpki 2 months ago from Radford, VA

      Hey Brian! Glad to hear it helped!

    • profile image

      Brian 2 months ago

      Just wanted to give a shout out for this article. My dog kept throwing hair at our battery fan and it finally let us know.

      Followed the instructions, problem solved. Thank you!

      2