My door locks are struggling. Plus unlock on the car and the lock will move a tiny bit, but won’t actually unlock the car. Sometimes it happens the other way around. Lock the car, horn sounds, alarm turns on… but the car doesn’t actually lock. I live in a hot climate if that matters. Anyone have any idea whats going on here?

 

One of the most well known problems of the car, weak lock solenoids.

 

replacing them is a bit of work, here's a video:

Luckily, parts are fairly cheap, here is an example
https://www.carparts.com/details/Inf...E&gclsrc=aw.ds

This is how they die, they simply move less and less. haven't had to do it yet on my G35, but I have done these on a lot of cars over the years, they all die. Not a lot of fun but necessary

 

I think the actuator you linked to is for sedans only and that the coupe uses a different (and more expensive) one. I don't recall seeing the actuators themselves available separately for the coupe, it's usually the entire assembly. I'd love to be wrong because both of mine could use replacing. I've also seen write-ups here of generic actuators made to work on the coupes, but personally it's a bit sketchy for my tastes.

 

I see what you mean:
https://www.z1motorsports.com/door-l...xoCWmMQAvD_BwE

Now I am confused as the Infiniti dealer site shows the original item as well. But I can see the assembly doesn't have this piece. Apologies.

 

My door locks will get weaker if I keep cycling them like 5 or 6 times in a row.

And if I park my car with the driver door facing the hot sun for a few hours, that lock will stop working til it cools off.

 

Yeah, that's the actuators. This is so common with cars today. I've replaced them on BMW, Hondas, Toyotas, Chevy's, whatever. They last a good decade then start to get slow. At 15 years they are often done. And they are never in an easy place to just pop out. On my camaro, it's riveted in, so you have to actually drill it out. Bleh.