The black button unscrews.

Do you have a 96-98 or a 99-00 Civic. The latter has the keyless control unit integrated into the stereo whereas the latter has a separate control unit behind the driver's kick panel.

 

you can pull it with force but you run the risk of breaking your kick panel, or you can use a panel pry tool to pop the plastic push button off.

If you have a 96-98 civic with factory keyless then your radio needs to remain in the vehicle for the factory keyless entry to work. If you want to put an aftermarket radio in then you can pick up a vehicle harness from an install shop that allows you to install an aftermarket radio and still have the factory radio plugged and remain hidden behind the dash. Heres what the harness looks like:

 

I have the same car, 99 civic. Car came with aftermarket stereo. I tried doing that thing where you turn the engine to position 2 and then pressing lock and turning to 1 back and forth a few times, but I don't think it works. The factory keyless FOB shows the red led when I press the button so it shouldn't be out batteries..

 

99 civic doesnt need to have the factory radio remain in the vehicle. Have you verified your civic is equipped with factory keyless entry?

 

The keyless entry connected to the OEM radio IS ONLY FOR '96-'98 Civics, the 99+ models DO NOT REQUIRE the OEM radio to be installed for the keyless entry to work.

 

You might be correct about the 99 civic but it certainly is incorrect with my 98 LX. I was told and it turned out to be correct that all LX models for '98 already came equipped (wiring wise) with the keyless entry and all you needed to do was purchase the OEM keyless remotes. I did that and it works perfectly. It cost me $69.

So the lesson I learned was that a honda dealer was willing to charge me $150 to program the remote which takes all of 5 mins while making it seem like they would have to install additional wiring etc. I almost got taken until I read on the internet and found out the real truth.

It appears that at least for the '99 LX, the same is true. it comes pre-installed with all the necessary wiring and all that is needed are some OEM remotes.

 

I think you misunderstood what I was saying. You actually proved my point. If the vehicle is equipped with factory keyless entry then you can just buy some factory key fobs and program them yourself and work. However if the vehicle isnt equipped with factory keyless entry then factory keyfobs are useless for the vehicle.

 

I understood your first post. I was simply informing you that as far as I know, the 6th gen LXs all came pre-installed wiring wise so all that was required was to purchase the remotes. I can see now that you were making a general statement. I thought you were applying them to the 6th gens