Step-by-Step Guide: How to Install a Rain Sensor for Automatic Wipers on Honda Accord 2018 EX-L

Hi everyone,

If you're looking to add automatic wipers to your Honda Accord 2018 EX-L model, installing a rain sensor is a great way to do it.

I have had an accident with my windshield when a stone hit it, so it had to be replaced. In this case, I ordered a windshield from the Touring model, which has the prep for a rain sensor. After reading the service information and schematics, I discovered that it should be possible to install a rain sensor on my EX-L to get automatic wipers functionality.

Here's how I did it:

Materials:

• Touring Windshield 73111-TVA-A31
• Rain Sensor 38970-TVA-A02
• Cable Harness 32156-TVA-C70
• Clips 91561-TVA-A01 x4
• Connector Pin - Male Pin B Small x2
• Wire - Yellow and Pink, each about 40cm in length
• Crimp tool
• Utility Knife
• Textile Tape
• Urethane Tape
• Depinning Tools
• Aluminium Tape - Thick, TESA 56223-00000
• Trim Removal Tools
• 8mm Socket
• Philips or JIS Screwdriver
• Two Flat Screwdrivers

Directions:

1. Disconnect the battery before starting any work.
2. Remove the headliner by taking off all the components that are attached to it. The hardest part is removing the handles.
3. Remove the black cover from the windshield. First, remove the small cover behind the rearview mirror. Then, push the big cover up and pull the part near the headliner, and then pull it to the front. Disconnect all cables and remove the rearview connector from the windshield, which is on a clip. You can also install the rain sensor at this point.
4. Clean the sticky surface of the rain sensor with wet wipes.
5. Remove the eight handle covers using a special tool. Alternatively, you can use two flat screwdrivers. Insert one from each side behind the cover, push hard and pull towards yourself. Then use pillars to remove handle holders.
6. Remove the interior lights. For the back one, remove the lens with trim removal tools, unscrew two screws, unclip harness from the housing, and disconnect the connector. For the front interior lights, open the eyeglass box and remove two screws, carefully remove the lenses, pry from the inner side, remove the screw from each, pull the housing to the front and remove it. Remove all connectors. Behind it on the chassis, there is a sunroof connector that needs to be disconnected. You also need to unclip the harness from the chassis.
7. Remove all pillar covers. The front ones are easy: remove rubber door seals from the top, remove the cover on top with "airbags" title, pry on top short side, unscrew 8mm screw, and pull the cover out. For the middle pillar covers, just push top part of the bottom black plastic, remove the clip cover on top, bump hard on the clip, replace it with a new one, remove the cover. For the rear pillars, it's similar to the middle ones; there is a clip on each that needs to be cracked and replaced.
8. Remove the cable harness from the front left pillar. It is on two clips, and you need to disconnect both connectors.
9. Remove the head restraints from the front seats.
10. Remove the two gray clips from the headliner near the rear windshield using a trim tool. You need to pull hard, but don't worry; they won't crack.
11. Remove both sun visors and sun visor holders. The sun visors have a hook on the front side that needs to be pushed and rotated so that the hook can rotate with the visor. Then unplug the connector from each. The holder is easy to remove; just rotate it clockwise.
12. Now that the headliner is free, it should fall down. To replace the harness, you need to unclip it in the center front area - there are three clips. You also need to remove all aluminum tape holding it and unplug ANC connectors.
13. Install the new harness and apply new aluminum tape in all places.
14. Install the headliner back, install sun visor holders, then two gray clips on the rear, and continue in the opposite way, but do not install handles and pillar covers yet. You can now test the car to see if everything is working as expected. Behind the front interior lights, there is one more connector on the Touring harness for HondaLink. You should apply urethane foam on it and tape it.
15. If everything is working as before, then you can proceed with installing pillar covers (except for the front left one) and handles.
16. Now for the electrical part. On the new harness, there are more cables on the secondary connector near the front left pillar. You are interested in the Yellow and Pink cable, which come from the rain sensor.
17. Yellow is for the wipers LIN bus, and Pink is for automatic headlights. You need to connect both, or else the exterior lights will be blinking in automatic mode.
18. Prepare two wires, one yellow and one pink. On each wire, crimp a pin. I also soldered it to ensure 100% contact because my crimp tool is not 100% compatible with this pin type.
19. Remove panels from the dashboard: bottom black one, disconnect wires, remove rubber door seal, and remove the side black panel. It is also mounted by a screw at the bottom.
20. Remove the vehicle connector from the holder - insert a flat piece of metal (from depinning tools) to unlock it from the holder and push up.
21. Insert pins to the vehicle connector on places where they are on the new harness connector. You need to remove the white retaining tab from the connector first, and then you can insert pins. Tape wires with textile tape along their whole length, keeping 5cm on each end.
22. Next, there are two white connectors attached to the fuse box on the right side. Unlock them similarly to the previous one. Disconnect cables, remove insulating tape from the harness if it's there, and find yellow and pink cables - check photos. Using a utility knife, carefully remove insulation and wind each wire around the respective cable we added. Insulate each with textile tape and then tape them to the harness.
23. Disconnect the original light sensor located on the dashboard in front of the passenger side. Push out the windshield vents cover with a trim tool and then remove the sensor and disconnect the connector. Apply tape and urethane foam to the connector and insert it back.
24. Connect the battery back and drive the car for a while to initialize systems. Then you can test the sensor. Switch the wipers to "intl" and cover the sensor with your hand; the wipers should try to wipe. Switch the lights to auto, cover the sensor, and the exterior light should turn on.

That's it! Installing a rain sensor on your Honda Accord 2018 EX-L can be a bit of a process, but with the right tools and patience, it's definitely doable. If you have any questions, feel free to ask!

To install the rain sensor, you can also disassemble the new harness and create a separate one. If you choose this, you will also need to wire +12V and GND, which can be taped from the original secondary connector (the one with only three wires on it). This alternative method can save you a lot of work with removing the headliner and replacing the harness. However, I prefer a cleaner job, so I replaced the whole harness.

Disclaimer:

The instructions provided are for informational purposes only and are intended to provide general guidance on the installation of a rain sensor on a Honda Accord 2018 EX-L. Any modifications or changes to your vehicle should be done at your own risk. It is important to follow all safety procedures and manufacturer's instructions when making any modifications to your vehicle. Improper installation or use of the rain sensor could result in damage to your vehicle or injury to yourself or others. It is recommended that you consult a professional mechanic or authorized dealer if you are unsure about any steps in the installation process. The author and publisher of this article are not responsible for any damages or injuries resulting from the use of this guide.

A pillar secondary connector:


Connector where we tap cables: