Home / 2009 – 2011 Civic Hybrid Plug-and-Play Car Harness Installation Instructions

2009 – 2011 Civic Hybrid Plug-and-Play Car Harness Installation Instructions

(Click on below image for larger

Time Required: Approx 1-1.5 hours

Tools Required:
8mm, 10mm, 12mm, 14mm sockets
Zip tie cutters or scissors
#2 phillips screwdriver

Recommended: Volt meter, trim panel removal tool

1) Open the hood and disconnect the 12v battery negative cable. This is cirtically important as we will be removing the 12v battery cables in the IPU compartment. If the battery is not disconnected the live battery cables by the IMA battery will very likely short to the body of the car!

2) To remove the rear seat, locate and remove the 10mm bolt at the center passenger’s left hip. Some Civic’s have a second bolt at the right hip.

3) Pull up on the front edge of the lower cushion to release retaining clips.

Remove the seat-bottom cushion from the car.

4) Remove the two bolts at the lower corners of the seat back. Slide the seat back straight up toward the ceiling and remove it from the car.

5) Remove IMA breaker cover and turn off IMA battery. Remove IMA compartment cover.

6) The IMA battery is on the right side of the IPU compartment. The left side of the IPU compartment is occupied by what we will call the “IPU control assembly”. Both need to be removed for the gird charger installation. We will begin by removing the IPU control assembly to simplify the IMA battery removal and gain access to the IPU cooling fan.

7) Begin by removing the three 10mm bolts holding the 12v battery harness from the bottom area of IPU control assembly. A small flat head screwdriver makes opening the positive charge protective cover very easy. Tuck out of the way as shown.

8) On right side of IPU control assembly, remove the two 10mm bolts for the IMA battery main connection. Then remove the three IPU sub-harness wire plugs as shown.

9) On left side of IPU control assembly, disconnect the IPU compartment sub-harness plug, IPU fan connection, and 10mm ground bolt.

10) On bottom center of IPU control assembly, remove orange 3 wire plug and gray retainer clip holding wire to IPU control assembly. Don’t forget to detach the gray clip, otherwise the IPU control assembly will not be able to be removed.

11) On bottom center of IPU control assembly, shift the IPU compartment sub-harness upward to gain access to IMA input cable cover. Remove the two 10mm bolts holding IMA input cable cover and remove cover.

12) Remove the three blue colored 10mm bolts holding IMA input wires noting which wires connect to each point on IPU control assembly. This is not hard due to wire lengths being very specific to each connection point.

13) Remove four 12mm bolts and lift IPU control assembly out of IMA compartment and set it aside. This is what the IPU compartment should look like.

14) Next remove the IMA battery.

This is done by removing four 12mm bolts that hold the battery in place. Carefully lift the IMA battery out of the car and place it on it’s flat end with the junction board facing up as shown.

The battery is 66 pounds, so get a helper if needed.

15) Re-check to MAKE SURE the IMA battery is still off!! If it is on the next few step could kill you! While not required, you can wear rubber gloves if you want to be super careful. Begin by removing the two platic plugs that cover the battery to junction board bolts. These can be easily pried off with a small flat head screwdriver.

16) Remove the IMA battery wire harness from the junction board by unplugging the three plugs shown and carefully pulling the wires out of their retaining clips.

17) Remove the eight 10mm bolts that hold the junction board to the IMA battery. A magnetic pick-up tool makes removing and reinstalling the 10mm bolts much easier.

I recommend having one of these tools before attempting the installation.

18) Lift the junction board straight up to remove it from the IMA battery. Do not touch any of the exposed IMA battery surface!! The sub-pack end bolts are electrically charged and can kill you!

Only touch the junction board, which is safe to handle.

19) Turn the junction board over and remove the small Phillips screw in the bottom left corner as indicated in the photo.

Be careful not to strip this screw while loosening and tightening. Use firm downward pressure on the screw and turn carefully.

20) On the supplied Car Harness, carefully bend the charge negative ring terminal to approx. 90 degrees as shown.

21) Install the charge negative wire onto the junction board as shown.

22) Reinstall the junction board onto the IMA battery.

Install and tighten the eight junction board to IMA battery bolts. A magnetic pick-up tool will make guiding the bolts into place in the deep pockets of the junction board much easier.

Also install the IMA battery wire harness, and the two black plastic plugs.

23) Reinstall the IMA battery/car harness assembly into the IPU compartment.

Securely tighten the four 12mm bolts that hold the IMA battery in place.

24) Position the Car Harness across the IPU compartment as shown. The end of the PET sleeve should be just outside of the IPU compartment.

Plug the Prolong plug-and-play car harness cooling fan wire assembly into the IPU fan wire harness at the white four wire connector.

Note: The image shows a 2006-2008 Civic Hybrid. Your charge negative wire will already be installed on the battery and, along with the red charge positive wire, should be routed across the IPU compartment.

25) Re-position/Re-install the IPU control assembly in the IPU compartment. (Just put it in place, do not make any wire connections yet).

Verify the three IMA input wires at the bottom of the IPU control assembly are back in their proper place and not caught behind the IPU control assembly.

Once confirmed, securely tighten the four 12mm IPU control assembly bolts.

26) Route and install red charge positive cable and secure with single small zip tie provided as shown. Trim excess zip tie. It is normal for the red wire to have some black heat shrink tubing on the end as this is protecting the diode that protects the car harness in the event of an electrical short.

Sorry for the blurry pic, the camera focused on the orange plug in the foreground instead of the red wire connection point. We will replace this photo as soon as possible.

27) Install the three IMA input wires using the blue marked 10mm bolts.

28) Install and the IMA input wire cover with the previously removed two 10mm bolts.

Install the orange three wire plug & gray retaining clip.


29) If you previously removed the two circled plugs, be sure to reconnect them.

(Removal of these plugs is not required to complete the installation, but may make it easier)

30) On right side of IPU control assembly verify the red charge positive cable is installed and tight. Install the negative IMA battery 10mm bolt and tighten.

Install the three previously removed wire harness plugs as shown.

31) Route red and black wires and secure to IPU compartment sub-harness with two large zip ties provided as shown. Trim excess from zip ties.

32) IMPORTANT – Test the charger before re-assembling the vehicle. Always connect the Charger to the car harness before plugging it into the wall and unplug it from the wall before disconnecting it from the car.

To perform the initial function test: First, make sure all fingers and tools are clear of all wiring and IMA battery components. Plug the Charger into the car harness. With the IMA battery circuit breaker still turned off, plug the Charger into the wall. After a few seconds, it should read approx 205 volts on the meter and both the charger and IPU fans should be running. Next, move the IMA battery circuit breaker to the on position. You should see the voltage drop as the charger voltage equalizes with the voltage level of the battery pack. This should happen quickly. The voltage level should be stable and not fluctuating. Both fans should still be running. If anything is wrong, stop and contact us. If the fan is ‘pulsing’ (powering on and off) every few seconds, stop and contact us.

This completes the test. Unplug the Charger from the wall, turn the IMA battery circuit breaker off, and disconnect the Charger from the car harness.

33) Other than the short installation tests, do not run the Charger with the IPU compartment open or only partially installed. The cover MUST be installed with all bolts properly tightened and the IMA breaker cover installed in order for the IMA battery to be properly cooled while charging. If you run the charger with the IPU cover off for any length of time, you WILL cook your battery!
34) Reinstall the 12v battery harness by connecting the three 10mm bolts and closing the red battery cable cover.

35) On left side of IPU control assembly, reconnect the IPU compartment sub-harness plug, IPU fan connection, and 10mm ground bolt.

36) Open the trunk, and remove (1) bottom cover, (2) rear sill cover, (3) right side cover, and (4) front cover (optional)

37) Route Car Harness into trunk area as shown

38) On right side cover, cut 2″ x 2″ ‘X’ in location shown. Remove padding from rear of cut to gain access.

39) While re-installing right side cover, route Car Harness through slot in right side cover.

40) Reassemble the remaining trunk liners in the reverse order of removal and reinstall all trim fasteners.

41) Reinstall the IPU compartment cover, turn the IMA breaker on, install the IMA breaker cover, and reinstall the rear seat.

42) Reconnect the 12v under-hood battery. You are done!

Click here for the Prolong Battery Charger User Guide.