Introduction
3rd Gen Integra (including non-R and R) has an electronic rear trunk release with a little black rubber slider at the trunk, instead of pulling the latch from the front driver seat. This is a convenient design, since you can open the trunk (if door unlocked) by standing at the trunk instead of walk back to the seat. I will call this as electronic hatch latch open assembly.

Added on 2024-07-25: In addition, it has an electronic lock build into the latch assembly. This post is edited to include this electronic lock failure. The electronic control rear hatch lock has a motor that is identical to the latch above.

Simplified diagram showing both electronic lock, and hatch slider switch, and related components

3 common problem areas are indicated in above diagram for you to get a complete picture of the problem area, which is covered in this post:
1. Electronic Trunk Opener - This is the most common part with most Integra owner share about. It is a black color box located below the rear trunk latch
2. 12V relay - this part is highly reliable. Much less Integra owner will write about it. It is a much smaller than regular car relay. Located near the power antenna in left wall of the trunk. 4 wires connector
3. Electronic Trunk Lock - This is the least common part that failed, and hardly any Integra owner will talk about in detail. Integrated into the trunk latch assembly with 6 wires connector

Problem #1: Problem in Electronic Trunk Opener assembly
However, this electronic hatch opener actuator (trunk opener) degrades and most likely stop working completely after 10 yr or earlier. Inside the actuator, there is an electric motor. When the electric motor getting too weak to turn the actuator, sliding the level at the trunk will not able to open it anymore, and you have to fall back to the car key (black key, not the gray key) to open it. This is normal for any electric motor to wear off, including water pump, home vacuum, A/C compressor, starter, power door lock, etc. Typically, the carbon brush will wear off, and needs to be replaced. However, no car dealer or mechanic will perform this for you, except DIY.

Inside the actuator, there is a high torque electric motor, which its carbon brushes worn off due to usage. The older the car, the more its carbon brushes will wear off. This post describe how to get another new carbon brushes to replace it for few $$$.


Replacement Part & Cost
There is no aftermarket cheap actuator unit, while a new unit cost ~ CAD$120 - $150 in Canada, and it is a special order unit which you can't return if it doesn't work. This is a $600 dealer repair, inclusive of labour.

Luckily the Acura uses Mabuchi FC-280PC 22125 motor, which is easy to source from eBay and Amazon. China made motor cost as little as ~ CAD$3, while authentic Mabuchi cost ~ CAD$13. You can make the decision base on how long you would like to keep the car.

Following is the specification from Mabuchi homepage:
FC-280PC/SC - high torque, non-continuous used 12V motor
W x L x H: 24.2mm x 30.5mm x 18.3mm
Distance between 2 power connector: 10.6mm
With PTC thermistor: Yes - extra rectangular carbon on the brush plastic cover

Mabuchi is produce one of the best car electric motor to use for door lock, folding side mirror, and trunk. I highly recommend choosing Mabuchi, if you have any doubt. Toyota and Lexus are using this exact motor model as well.

When picking other cheaper option, please ensure to pick one that is high torque. Continuous use is optional, as non-continuous will be smaller.

Cause of failure
This Mabuchi motor is designed to lock/unlock door/trunk/mirror with high torque value. For this kind of high torque motor, it is not design to turn on for long period of time, and will degrade (carbon brushes) sooner if car owner slide the level (to open the trunk) for extensive length of time.

The design of Integra trunk is such that you have to slide the level (turn on the motor), and lift up the heavy trunk at the same time. The longer the motor run, the sooner it degrades and

Following are several scenarios where I think it could degrade its life:
1. Turn on the motor for extensive time while lifting the trunk
2. Rust on the level which causing the level have to manually slide back to off position manually. This indirectly causing the motor to turn on longer than usual
3. Rust build up on the sliding level which causing it stuck in the on position. The electric motor turns on and run for extensive period of time, and wear off earlier

When the carbon brushes worn off, we can order another new motor for few dollars, and get the motor working again. This is the same technique we repair the brushes in electric blenders, and power tools.

Problem Electronic Trunk Opener

Part Ordering Description
Search for "Mabuchi FC-280PC" in eBay or Amazon to look up this part

For example:
Amazon: eBay: 4pcs 20mm Door Lock Motor FOR Mabuchi Lexus Honda Toyota FC280PC 22125 Repair | eBay

For this repair, you can get either 11.45mm short shaft, or 20mm long shaft. We are only going to replace the carbon brushes, which is the whole plastic cap assembly.

Integra glue the gold metal gear to the shaft very tightly in this motor, and it is very hard to remove. Toyota & Lexus uses plastic gear which is easier to remove and install into new motor. Luckily there are many owner are able to replace the carbon brushes cap successfully, and proven that this fix resolved the issue. Therefore, I do not buy additional gear removal and installation tools to do this job.

Steps



Remove 3 screws as indicated mounting the electric truck actuator assembly to the metal bracket



Remove the connector



Electric truck actuator assembly with the lock latch




Electric truck actuator assembly




Inside of the actuator




Uses flat head screwdriver to lift up the motor




Slide under the round cap to lift up the motor




Gold color metal screw in the Mabuchi motor. Beware of the small white plastic cap at the end




Actuator with the motor removed




White plastic cap which we are going to replace, and carries the carbon brushes




Uses 3mm wide flat head screwdriver to open the cramp holding the plastic cap




Slide the screwdriver into the hole to remove the metal latch. Just remove 1 side, so that it holds better when we re-assemble




Double check you keep the small plastic end cap




Uses small cramp or adjustable wrench to remove the rubber cap. You need to squeeze the rubber cap to deform a little in order to remove it




You can test the old and new motor by connecting them into 12V battery or power supply. You will see the old motor still turns, while the new motor spin much faster




Install carbon brushes (rubber cap) from new unit into old motor




Showing both old and new motor with carbon brushes swapped




Install motor back into actuator




Ensure the white plastic end cap is attached




Before covering it back, double test with 12V power supply to ensure the motor turn. I accidentally bend the contact metal point and causing it not to turn




Put the cover back




Install 4 screws




Apply 12V power again and ensure this latch turn from right to left. Push it back to right to repeat the test if needed



Connects the connector, and slide the actuator back into the mounting bracket. Ensure that the pin is in the hole, else it won't open the trunk



Install 3 screws to mount back to the metal bracket. You can test it with just 1 screw to ensure the hole align correctly. Realign if needed

Lastly, my YouTube video showing the end result

Testing Trunk Actuator after Replaced Electric Motor

Testing the rod movement

Testing the trunk

Problem #2: Electronic Trunk Lock Assembly
This electronic lock actuator degrades the same as latch opener actuator above. The more you lock the car, the more the internal electronic motor will degrade. When the electric motor getting too weak to turn the actuator, it will either unable to lock or unlock the hatch lock. This leads to no power to the electronic hatch opener relay, therefore, above electronic hatch opener actuator will never get any power., even you unlock the car (this hatch electronic lock remains in the lock position).

Inside the actuator, there is a high torque electric motor which is exactly the same model as abov electronic hatch latch open assembly. The motor's carbon brushes worn off due to both lock and unlock usage. This post describe how to get another new carbon brushes to replace it.

Cause of failure - Electronic Trunk Lock
This Mabuchi motor is designed to lock/unlock the trunk/mirror with high torque value. For this kind of high torque motor, it is not design to turn on for long period of time, and will degrade (carbon brushes) sooner if car owner slide the level (to open the trunk) for extensive length of time.

The design of Integra trunk is such that you have to slide the level (turn on the motor), and lift up the heavy trunk at the same time. The longer the motor run, the sooner it degrades.

Following are several scenarios where I think it could degrade its life:
1. Turn on the motor for extensive time while lifting the trunk
2. Rust on the level which causing the level have to manually slide back to off position manually. This indirectly causing the motor to turn on longer than usual
3. Rust build up on the sliding level which causing it stuck in the on position. The electric motor turns on and run for extensive period of time, and wear off earlier

When the carbon brushes worn off, we can order another new motor for few dollars, and get the motor working again. This is the same technique we repair the brushes in electric blenders, and power tools.

Troubleshooting - Electronic Trunk Lock
This troubleshooting is based on 6 wires connector that is connected to electronic truck lock, which is also called the trunk latch.
1. Measure voltage of blue/white wire. Put positive probe at blue/white wire, negative probe at car's body
1.1. Expects 12V regardless car is lock or unlock
2. Measures resistant between blue/white wire and blue/red wire when power lock is in locked position
2.1. Open - infinite resistant
3. Measures resistant between blue/white wire and blue/red wire when power lock is in unlocked position
3.1. 0 ohm
4. If you don't have a multimeter, then uses your finger to slide below this electronic trunk lock. There is a white plastic latch that is visible, and touchable by fingers
4.1. The white plastic rod is not visible from top position as it is blocked by metal bracket of the car body
4.2. You need to climb inside and look up from the bottom with flashlight
5. Uses your finger to push up the white plastic rods (lift up) to manually unlock this electronic trunk lock
6. Repeat step 3, and wire blue/white and blue/red should be connected (0 ohm), and both are giving 12V

This electronic lock will slowly degrade as the motor is slowly weaken. For my car, it took 1 year to intermittently failed to lock/unlock the trunk, and finally remains in the lock position, so trunk was never able to be opened.

Temporary Workaround - Electronic Trunk Lock
You can uses your finger to lock and unlock this electronic trunk lock:
1. life up the white plastic rod to unlock the trunk
2. pull down the white plastic rod to lock the trunk

Please be aware that if this actuator fully failed (not intermittent), then above will permanently keep the trunk is the lock or unlock position. For example, once I unlocked manually by hand, then the trunk can always be open, even the power lock (central lock) locked the car. This is b'cos power trunk lock actuator is unable to lock the trunk.

Replacement Part & Cost - Electronic Trunk Lock
There is no aftermarket cheap actuator unit, while a new unit cost ~ CAD$120 - $150 in Canada, and it is a special order unit which you can't return if it doesn't work. This is a $600 dealer repair, inclusive of labour.

Similar to power trunk opener/actuator, Acura uses Mabuchi FC-280PC 22125 motor, which is easy to source from eBay and Amazon. China made motor cost as little as ~ CAD$3, while authentic Mabuchi cost ~ CAD$13. You can make the decision base on how long you would like to keep the car. The China made motor has last since 2016 until today (2024) ~ 8 yr.

Following is the specification from Mabuchi homepage:
FC-280PC/SC - high torque, non-continuous used 12V motor

Mabuchi is produce one of the best car electric motor to use for door lock, folding side mirror, and trunk. I highly recommend choosing Mabuchi, if you have any doubt. Toyota and Lexus are using this exact motor model as well.

When picking other cheaper option, please ensure to pick one that is high torque. Continuous use is optional, as non-continuous will be smaller.

Problem #3: Electrinic Hatch Opener Relay
There is a small 12V relay sit before electronic hatch latch opener. When car is unlocked, the rear electronic trunk lock will be in unlock position, then this relay will get 12V power. When the relay failed, even you slide the switch to open the rear trunk, the relay won't click. This indirectly won't supply 12V to turn on the electronic hatch opener.

This small 12V relay is relatively rare, but it is a standard electronic part. You can buy from electronic shop instead of dealer to save money. The cloest quality relay I found is Panasonic CA1A-12V-N-5 12V 20A


Location of 12V Relay on left side of trunk

Relay connector. Orange wire is 12V when unlocked

Cause of failure
This relay is turn on whenever you slide the trunk switch to open the trunk. Every relay designed to have an expected life by number of time the relay turns on. For Panasonic CA1A-12V-N-5 12V 20A, it is not design to turn on 100,000 time minimum with you holding the trunk slider for 2 sec. For my own usage, I uses the trunk daily 4 times/day. I like to play with the trunk slider 3 times everytime I open it. So my usage per day is 4 x 3 = 12 times/day. Per year of usage is 12 x 365 = 4380 times/yr.

So 100,000 times will last 100,000 / 4380 = 22.8 years

The longer the relay turns on, the sooner it degrades. If you don't have a strong arm to lift up the trunk, then the longer you will keep the power to the relay. Moreover, if your trunk's shock is weak, you will keep the relay turn on for longer as well. Both of these reasons are why car owner will turn on the relay for longer time.

Following are several scenarios where I think it could degrade its life:
1. Turn on the relay for extensive time while lifting the trunk, like you like to play with the electronic trunk
2. Turn on the relay for extensive time while lifting the trunk, due to you don't have much strength to lift up the trunk
3. Turn on the relay for extensive time while lifting the trunk, due to the trunk shock is weak, and needs more strength and time to lift up the trunk
4. Turn on the relay for extensive time while lifting the trunk, due to both of the trunk shocks are broken, and needs more strength and time to lift up the trunk

When the relay failed, it will fail in sudden. So if this is intermittent, then it could be due to 2 other actuators problems listed in this post.

Troubleshooting
1. Ensures the car's power lock is in unlock position
2. Disconnect the connector to the 12V relay
3. Locates orange color cable, and measures its voltage. Puts positive probe to it, and negative probe at any bolt on the car's body (ground)
3.1. Expected 12V when power door lock is unlocked, 0V when power door lock is locked. Continue to next step
3.2. If constant 0V, then this relay is not the problem. Look into the electronic trunk lock
4. Removes the relay, and put it on your hand. The relay's front (with writing) should face you
5. Measures the resistant of the right 2 pins. Its resistant should be 80 ohm
6. Meausures between other pins, and they must be open (no connectivity)
7. Connects 12V to the right 2 pins to power on it
7.1. Expects relay to turn on. You will hear a click
7,2. Measures the left 2 pins. The resistant will be 0 ohm
7.3. If no click, or click, but left 2 pins not connected, then the relay is bad. Replaces it

Replacement Part & Cost
This relay is commonly used in many car's manufacturers, but not Honda/Acura, so it is hard to find if you search for Honda. Typically Honda/Acura sell their relay ~ $30. Typically, Honda/Acura designed their relay in the fuse box in the hood, and driver side, but this relay is located in the trunk.

I can't find the part from Acura online part (manufacture's homepage), so I don't know the OEM part number and price.

If you want to replace this with other more common relay, you can uses any 4 pins auto relay. Ideally 12V 1A relay which is the required power to turn on FC-280 motor. Original 20A is over size.

Part Ordering Description
Search for "AC relay" in eBay or Amazon to look up this part. If you want quality part, search for Panasonic CA1A-12V-N-5. This should be 12V 20A.

E.g.

 

Great writeup, I just used a DEI 524N actuator to replace mine though.

 

how did you do that? The motor on mine was completly missing when i got it and the only key i have doesnt work in the hatch lock, but works in the doors and ignition.