This is a rear hatch repair experience sharing.

Most often rear hatch can't open issue that many encountered is the rear hatch motor broken (small DC motor carbon brush degraded), but not this one. This repair is about the hatch relay and its wiring that causing the rear hatch motor not getting 12V power on sliding the hatch switch.

Let's start with symptom:

1. Slide the rear hatch open slider to open the rear hatch
2. The hatch motor doesn't open the hatch
3. Unlock the power door, and slide the rear hatch switch again
4. The hatch motor doesn't open the hatch
5. Now, put your hear towards the antenna area to listen for relay clicking sound, then slide the hatch opener switch
6. No relay clicking sound is heard from the relay below the antenna
7. Open the rear seat, and crawl into the rear truck, as well as stay close to the antenna area, and listen for latch relay sound
8. Asks someone to slide the hatch opener switch, but no relay clicking sound is heard from the hatch relay below the antenna
9. If you don't hear the hatch relay clicking sound, then your issue is due to the relay and its connector issue, but not hatch motor failure

Diagnostic #1 hatch slider switch:

1. Ensure power door is unlock
2. Disconnect the 2 wire connector at the hatch relay, and get your volt meter ready
3. Measure across these 2 wire at the connector for 12V, then slide the hatch opener slider
4. You must get 12V if the hatch relay works (or relay connector). If you hear a relay clicking sound, then you must get 12V

Diagnostic #2 unlock hatch by key

1. Power door can be either lock or unlock for this test
2. Put the car key into the rear hatch key area to open the hatch
3. Same as above to prepare the measure the 2 wire connector of the hatch motor
4. Turn the car key to the right (CW) to open the hatch
5. You must hear relay clicking sound, as well as 12V at the hatch motor connector

Diagnostic #3 test hatch relay

1. Video:
   You Tube
2. Ensures the power door is unlocked using power door switch, or car key
3. Removes the rear left plastic panel. There are 12mm bolt you have to remove. One covered by a small plastic cover above the rear spring, and another is closer to the rear seat
4. Removes a small Philips plastic screw and trim cover plastic on the truck floor that is holding the left plastic panel down
5. After removed above 3 bolt/screw, then pull the left plastic panel open to get access to the antenna and hatch relay area
6. You don't need to remove the entire left plastic panel, as the opening is big enough for this work
7. Look above the antenna motor area, and you will see a 4 wire 12V small relay
8. While doing this, you most likely will discover rust, water stain in this area, as moisture/water is the cause of this failure
9. Disconnect the 4 wire relay connector and prepare to test its voltage
10. By looking at the relay's pin, the 2 copper terminal is connecting to the latch motor connector. White/green from battery, yellow/red to hatch motor
11. The other 2 silver color terminal is to power the relay. Orange from battery (if door unlocked), blue/white to sliding hatch opener
12. Prepare to measure orange wire at the relay connector that connects to the relay silver pin
13. By holding the relay connector latch facing up, the left 2 pin (female) is orange (12V) and blue/white (ground)
14. Orange wire will give constant 12V when door unlock, and 0V when door lock
15. Connect volt meter ground to the relay connector blue/white pin (lower left pin), and keeps positive probe at orange wire (upper left pin)
16. Slide the hatch opener, you will get 12V when switch slide to open position
17. If you don't get 12V, then shake the relay connector's wiring to remove surface rust. Mine has very minor surface rust that is invisible, so it didn't give me 12V between these 2 wires
18. After you confirmed you get 12V, connects to the hatch relay and test it by sliding hatch opener switch
19. Continue test if you don't hear relay click when open the latch (by switch or key)
20. The remaining of the test assumes your hatch relay is clicking, yet hatch motor's connector (yellow/red) doesn't get 12V. If you get 12V at orange wire, but relay not clicking when open hatch, then the relay is broken. Remove the relay and test with 12V on the silver pin to confirm relay is broken. It should be $1-$5 to replace it
21. Measure the white/green and the wire below it (or body ground). You must get 12V. If doesn't get 12V, bend the wire a couple times to remove surface rust
22. Measure the yellow/red wire voltage against body ground. You will get 12V when slide the latch switch
23. If you get 12V on yellow/red wire, then relay is supplying 12V to the latch motor
24. If you get 12V at white/green wire, but not yellow/red wire when open the rear hatch, but relay click, then the relay is broken as well. Removes the relay to test and confirm. Supply 12V to the silver pin, and measure resistant against 2 copper pins. When relay clicked (on), both copper pins should be shorted (0 ohm) and connected together

Hope this old car and car owner will find this common issue helpful.

 

I believe this is the issue my trunk is having as I don't hear my relay click. Thanks for the video, I've been iffy about pulling out my rear panel due to cracking the plastics, but I've been wanting to fix this issue.

By any chance you have the part number for the relay to get it from another source other than Honda? I believe Honda discontinued it...

 

I don't think is 12V SPST relay is broken, but surface rust at the relay connector. Open up the rear left plastic panel first to ensure the connects are getting 12V in and out.

The relay is a generic relay. OEM is Denso. It has a screw mount hole to mount to the metal body.
https://www.aliexpress.com/item/32832773385.html