I found old spare remote and after changing battery it worked fine.
So in my case it was broken remote.
The fact that IR/RF remote key tester was showing signal from my broken remote meant nothing.

Hello everyone,

So've I've been having the notorious flashing key light for some time now. None of my remotes work (replaced the batteries) and eventually the car wouldn't start. With the advice of some members on here, I was able to re-register the key and it would start. The thing is, if I leave the car over night and try to start it the next morning it won't start again. I have to re-register the key in order to get it started. Funny thing is that the key works fine all throughout the day but somehow "resets" when I leave the car overnight. I removed the rear bumper to try and clean the rear antenna like many people have done but when I removed it, there was no antenna?!? The only cable there was the one that connected to the license plate light. Is this also used as the rear antenna?? I have a '04 6-speed. Thank you in advance for any help.

Your 04 will not have the antennas. This only applies to cars equipped with the key card entry (proximity). I believe it was only available on '06 on. There are 6 antennas total. Here is a schematic of them with their part numbers.
6630A - BODY RELAYS & UNIT. Fits: Mazda | Jim Ellis Mazda

Is it possible that your battery is starting to go bad?

PaleRider, thank you for response. Its good to know that the '04's didn't have the rear antenna. I was worried my car was missing something.

Do you mean the car battery or the keyless remote battery? The car battery is less than a year old and is fine and I replaced the batteries for both of my keyless remotes and they still don't work. Do the '04 keys themselves have a battery inside them??

I was referring to the car battery. My Jaguar STR and my wifes Jaguar XF has all kinds of electronics in it. When the battery starts to get a little low it will start to cause all kinds of little electronic gremlins. Even though the battery is strong enough to turn the engine over and start it if the battery gets too low it will do strange things like this upon startup.

I know the RX-8 does not have nearly the electronics as the Jags but it is something that is easy to check. It is a shot in the dark but try to put a battery charger on you battery over night and see if this keeps your car from "forgetting" the keys when you go to start it in the morning.

thanks palerider for your input. I charged up the battery today and the key worked fine while i was driving during the day and made a couple of stops. it recognized the key no problem. i parked it at my garage for about 8 hours and just went out to see if it would recognize the key and it didn't. =( i had to re-register the key and started up right away. has ANYONE encountered this problem? i'm totally baffled.

thank you

Is there anyway you can leave the charger on the car while it sits over night to make sure the battery is not discharging some over night?

Could this be a grounding issue?

2004 , 6spd

:( I bought my 8 last week, the remote seemed to work fine when i was driving it home but on the weekend it just stopped... i have 2 remotes both dont seem to take programming. i did the diagnostics test (key on - off 4 times, door switch 3 = doors lock, trunk open, hazards and honk) that went fine... but i try to program either remote (new battery) and nothing happens...

Remove the bumper??
 

Once again, this site is great - I have an 06 Shinka and just started experiencing the red key light after driving it for the first time in the snow about a month ago (it handled great by the way!). I am assuming the snow kicked up into the sensor so I am going to clean it before replacing it.

My dealer confirmed it is the rear antenna under the rear bumper (FE95-67-6N0C) so now I need to take the bumper off. I am not a mechanic so could someone explain in detail how I remove the bumper???

THANKS FOR HELPING ME SAVE SOME CASH - my stupid dealer also wanted to charge me almost $600 to replace the sensor!

here is a diy
https://www.rx8club.com/do-yourself-...removal-34696/

I cleaned the terminals without removing the bumper, reset the battery and for the first 5 minutes, it works and i can open the trunk with the push button. Shortly after it doesn't work and the red light comes back. Does this verify that the antenna behind the bumper is good?

I just replaced the FOB in my smart key hoping that was the issue, but I think I'm experiencing the same thing as you guys. All the buttons on my FOB work fine, but when I get in the car, I cannot turn the ignition knob, and a red KEY flashes on the dash. Valet key works fine. I've tried reprogramming it with the 3 on/off combo, but that didn't help either. Maybe 1 out of 10 times I enter my car the knob will work.

To top it all off, in the previous owner's service history he provided me, he had the rear antenna 67-6N0C replaced, at $300+150 labour in April 2012.

nisaja, if one of the proximity antennas is not being recognized by the car it will not allow the buttons on the door handles to work, but will still allow the car to start withthe card key once inside the vehicle and it is detected by an interior antenna.

When you took off the panels I am willing to bet that one of the antennas came unplugged in one of the doors. I would pull the panels off and make sure the antenna is plugged in. I bet this solves your problem.

I am having a similar problem . Everything works EXCEPT for the driver door button and when pushing the trunk button on the remote it only works when its within a few inches from the trunk. All other buttons work fine and remote works from almost 20 feet away with brand new battery. Any suggestion? Could it possibly be the button itself on the door or the sensor in the door and or rear bumper?

My car had the same problem but it fixed itself. The trunk button is supposed to work only when the remote is a few inches away from the trunk. It won't work a few feet away. There's nothing wrong with that. You said only the driver door button doesn't work. Does the passenger door button work? When you unlock your doors using the remote, do both doors unlock?

The Passenger side button works. It unlocks both doors no problem. I was noticing from going back and forth that the drive side button with the issue the rubber on the button is much harder ( dried out) and feels like nothing is behind. I think my next step will be removing the door panel and seeing whats going on behind it.

I was curious about the sensors. Lets say you had two perfectly operating buttons and sensors. If the remote is on the driver side and someone else pushes the passenger side will detect and unlock? If this is the case I can determine that my driver side sensor is bad or disconnected (fingers crossed).

I just bought this car last week. 2007 GT This is the only issue with the car. I cant complain . I LOVE IT

That sounds like the driver side button is not working. No, when the remote is on the driver side and someone else pushes the passenger side button, the doors WILL NOT unlock. The remote should literally be right next to the button you're pressing for the doors to unlock. However, that does not mean your driver side sensor is bad. That's just how the car works :P You can press the button on the remote and unlock the doors from a distance.

I know man. I just bought mine like a month ago. 2007 as well. Love it to death! :D

mine is doing the same thing I have to check that rear antenna thank you guys

Rear Antenna Module ---- FE95-67-6N0C
 

I am just trying to figure out what and exactly where the module is located.

Is this it?

FE95-67-6N0C

http://farm4.staticflickr.com/3768/1...efd9cf58_o.png

ANTENNABKEYLESS from Mazmart.com

Had the same problems: Red key light on dash, button on outside of door wouldn't work, wouldn't autolock.
Solution: Took bumper off and cleaned the antenna and connecters with electrical contact cleaner.
Result: No red key light on dash, button now works, still does not auto lock.

Here's a pic of the said dirty antenna:
http://i58.tinypic.com/2pshwxv.jpg

Auto lock is now working too. :)

Foodstamps...I just cleaned my but still doesnt work. Did you do a batter reset after you clean these contacts?

https://farm8.staticflickr.com/7390/...624e8082db.jpg

Need to bump this, having troubles with my 04 similar to these. Key fob stopped working recently along with my locks and courtesy lights. With the key in the ignition everything works fine aside from my fob. When I pull the key out the little key light pops up immediately and shuts power off to my lights and door locks.

Anyone got any input? Tried resetting the key to no luck

battery is dead in the fob.

I'm not sure about the security light, but when my '04 OEM keyfob went bad recently, I changed the battery & it didn't work even though it tested good. It's a common problem.
The switchblade keyfob worked.

Search the "Keyless Entry not working" thread in Series 1 Troubleshooting