[Guide] Everything you wanted and didnt want to know about Clarity door actuator motor. 72150-TRT-A0

[Duxa]

2 years ago my Clarity's driver door actuator went bad, I wrote up an extensive guide on how to diagnose it here and replace it here.

At the time, it was a $140 part (from 3rd party but OEM), or $240 from a Honda dealer. My front passenger actuator is now starting to go, and the part is now $340 from dealer or $200 from 3rd party (OEM). Since I know that most of the time the issue is a $2 motor inside of these things, I decided to take one apart to take a look.

This is my old driver side actuator 72150-TRT-A02

The two halves, black and white are glued together, so there is no taking this bad boy apart without cutting or prying at it and hoping the glue gives before the plastic. So the optimal approach is to cut open the plastic to get to the motor.

The motor sits at around here:

I took a dremmel and slowly cut out a square, as you cut you can see that there is nothing where you are cutting, but you have to be careful not to cut too deep because you can hit the gears inside or the motor. Overall not very hard. Try to cut out as one piece so that you can glue it back on later with some Plastic JB Weld Epoxy (dont use superglue its too brittle and doesnt work on ASB well).

Also, do not cut the black part, you have to enter from the white side because all of the mounts and contacts are on the black side and if you cut through black side the motor will not have mounts to sit in.

I would suggest cutting less on the top, try to stay as I drew the red lines, this is because part of the gear mechanism relies on hitting some of this shell. What I cut above is fine however.

Motor dimensions:

Worm gear = 27mm
Motor body = 30mm
Motor + shaft (no worm gear) = 45mm
Shaft = 10mm
Shaft round width = 2mm
Shaft flat width = 1.5mm

This motor part number is sold in bulk to car manufacturers, its not sold as one offs to anyone, so any units you will find for sale are likely salvaged (not new). There may be drop in replacements with different part numbers but I cant vouch for any since I havent tried any of them.

 

[insightman]

@Duxa, I love reading posts like yours! I don't work on my cars anymore, but it's great to read detailed procedures from those who do.

I didn't even know what a door actuator is, so I googled the part number you listed and found this power latch on Amazon for less than $65.

 

[Duxa]

Edit

@Duxa, I love reading posts like yours! I don't work on my cars anymore, but it's great to read detailed procedures from those who do.

I didn't even know what a door actuator is, so I googled the part number you listed and found this power latch on Amazon for less than $65.

View attachment 24422

That is not the correct one (at least picture is not correct). It doesnt look like the one from Clarity.

Will it work? Maybe... Will it fit? Maybe... it looks to be a 3rd party non genuine part, or a part from a completely different car that wont fit. The opaque white plastic (cheap) is a giveaway. Also this one is held together via clips (cheap easy to make), while genuine OEM one is glued togehter, no clips.

No serial/model numbers being anywhere on it screams to me that this is 100% sweatshop fake part.

Here compare these:

 

[TC1782]

2 years ago my Clarity's driver door actuator went bad, I wrote up an extensive guide on how to diagnose it here and replace it here.

At the time, it was a $140 part (from 3rd party but OEM), or $240 from a Honda dealer. My front passenger actuator is now starting to go, and the part is now $340 from dealer or $200 from 3rd party (OEM). Since I know that most of the time the issue is a $2 motor inside of these things, I decided to take one apart to take a look.

This is my old driver side actuator 72150-TRT-A02

The two halves, black and white are glued together, so there is no taking this bad boy apart without cutting or prying at it and hoping the glue gives before the plastic. So the optimal approach is to cut open the plastic to get to the motor.

The motor sits at around here:

I took a dremmel and slowly cut out a square, as you cut you can see that there is nothing where you are cutting, but you have to be careful not to cut too deep because you can hit the gears inside or the motor. Overall not very hard. Try to cut out as one piece so that you can glue it back on later with some Plastic JB Weld Epoxy (dont use superglue its too brittle and doesnt work on ASB well).

Also, do not cut the black part, you have to enter from the white side because all of the mounts and contacts are on the black side and if you cut through black side the motor will not have mounts to sit in.

I would suggest cutting less on the top, try to stay as I drew the red lines, this is because part of the gear mechanism relies on hitting some of this shell. What I cut above is fine however.

Motor dimensions:

Worm gear = 27mm
Motor body = 30mm
Motor + shaft (no worm gear) = 45mm
Shaft = 10mm
Shaft round width = 2mm
Shaft flat width = 1.5mm

This motor part number is sold in bulk to car manufacturers, its not sold as one offs to anyone, so any units you will find for sale are likely salvaged (not new). There may be drop in replacements with different part numbers but I cant vouch for any since I havent tried any of them.

I would like to see the inside of the motor, seems strange that it would fail.

 

[Duxa]

I would like to see the inside of the motor, seems strange that it would fail.

I dont have tools to cut it open cleanly. But when I apply voltage it does spin, however one direction is louder than the other. I think it 'works' but is not as reliable. In practice it sometimes fails to lock or unlock, but not always. Probably an issue with resistance or something like that so that it doesnt have the torque/power its supposed to have.

 

[Duxa]

Follow up on this. I took the 2 failed ones apart. 2 different failures to the motor.

Front left one the best I can describe is "worn out", it just doesnt have the power to cycle the lock reliably... works most of the time but not all the time (and only in one direction, unlock direction, lock direction works ok, unlock has almost like friction).

Front right motor, the shaft mechanism is busted, with the actuator assembly cut open I ran power to it to test it and the issue was apparent, the shaft got separated from the coils. Or at least is loosely attached. Basically because the gear dead stop the motor, but it wants to keep rotating, the coils continue to spin (until car cuts power), but shaft is stationary because it is no longer attached to the coils.

Both failures are likely due to these motors wanting to continue spinning, but by the nature of how these work they basically get in a few rotations in and then are dead stopped from full speed to 0. This puts a lot of torque on the motor, and since these are cheapo $2 to $4 motors they cant stand thousands of cycles of this. First one failed after 4 years (roughly 4*365*4) ~6000 cycles. Second one failed after 6 years, (roughly 6*365*4) ~9000 cycles. Im counting getting in the car once (unlock, lock), and getting out (unlock, lock) once a day, some days this 0 times, others its 10 times per day, all depends.

On both actuators the plastic worm screw and gears were in pristine "line new" shape. No issue with those.

I think the design issue here is that the power is supplied for too long during lock/unlock, the motor wants to spin, but its stopped in its tracks and cant spin for far too long, heating it up and putting unnecessary stress on it. Additionally a design that allowed it to spin further would not put as much stress on it.

Anyways, to replace these through Honda its ~$340 for the part, and likely around ~$200 for labor. I replaced both of these, including taking the door apart, taking out actuators, cutting them open, replacing the motors, lubricating (lithium grease), and gluing the cut out piece back on (JB Weld Plastic Epoxy), putting them back on, re-assembling the door, all within about 1 hour. And the motors were ~$4 a piece. So 2 doors fixed for ~$8 instead of ~$1000.

The motors I got have the exact same markings (FK-280ST-15240) but have 2 green lines instead of blue lines, I tested them before putting them in to make sure the polarity matches, and it does (otherwise your unlock will become lock and lock will become unlock). So the green lines (instead of Honda's blue) either are a date code, or a supplier code (were originally supplied to someone else, not Honda). One thing to keep in mind, these motors are made as part of a supply chain, you will never find brand new ones, they dont exist in stores (not with matching model). But all 4 that I bought off ebay seem to be in like new condition. They work. Perhaps fell off a truck or salvaged off a new-ish car or part.

Im satisfied, and have 2 spare motors for 5 years from now when these fail again. Its interesting that the back ones havent failed likely due to child locks being on and therefore not seeing as many cycles as the front doors. Next time replacement will be quick and easy since the plastic door in the actuator assembly to access the motors is already cut out.