My interior button works to open trunk but my taillight button doesn’t ???? Any ideas on what to look at first

 

The first thing to look at might be the Factory Service Manual? Here:
https://www.nicoclub.com/service-man...F2005%2Fbl.pdf
Below that window you can "Click Here To Download A Copy" and then you can read up on the somewhat complicated Intelligent Key system.

But first, does the system work as expected everywhere else on the car? Do the door buttons unlock and lock the car? Does the ignition know when the i-Key is in the car, etc.? If all except that trunk button work - and you already know it's not the actuator because the dash switch opens the trunk - then look at the location of that rear antenna, the switch itself, the wiring harnesses, etc. Did it work before but suddenly stop working? Have you had any work done on the rear bumper?

 

I don’t know if there was any rear bumper work, it doesn’t loo like it, all other systems seem to check out as far as locks key fabs alarm
i posted a question also about my hazards not working and my cruise control light wont go out and cc dosent work I don’t know if that means anything

 

There is a trunk button lockout in the glove box, make sure you didn't turn it off.

 

But wouldn't that shut off the trunk release button to the left of the steering wheel? It's designed to keep the Valet from steeling your spare.

This in combination with the OP's other problems is a bit worrisome. Check for any water intrusion in the passenger footwell area and around the BCM?

 

Ohh yeah forgot that disables BOTH buttons.

I would unplug the harness on the tail light and ring it out with a multimeter, the blue and black wire are the opener, the other two wires are the light.

Blue to black (switch side) should have continuity when you hold down the button.

Harness side black should have continuity to ground.

Harness side blue should be 5vdc I think (not sure exactly, it's a signal wire from the BCM and it's usually 5vdc for signal).

 

This is on a coupe, right?

 

yes its a cpe, dumb question is this switch a separate piece than tail light? so i can possibly bye just that and replace

 

But wait ... '05 coupe? I didn't think the Intelligent-Key system was available on the coupe before '06. At least that's when it shows up in the FSM. Do you have the I-Key? Lock request buttons on the outside of the door, keyless ignition, etc?

 

That's sort of what I was getting at, but needed to confirm that this was on a coupe. The tail lamps with the trunk button integrated into the driver's side lamp were for model years 06'-07'. If the OP has an '05 than these were added on later - as many have done to their '03-'05s, myself included. These are a "plug 'n play" upgrade as far as the lighting is concerned, but the '03-'05's are missing one wire in the connector for the trunk opener to actuate. The trunk opener is for all '06-'07 coupes regardless if equipped with or without the Intelligent Key system.

 

Ah, interesting! So the tail lamp trunk button appeared on the coupe around '06 even without the I-key? Like it would open the trunk when the car was unlocked, and presumably when the glovebox "cancel" switch wasn't engaged? Maybe that's what's happening here.

So, b73, do you have the I-Key or the Remote Keyless Entry system? And I don't think you can buy just the switch as it's part of the lamp assembly. But I'd also be surprised it that's what has failed here. Seems like there's something else going on.

 

Correct, but it's not the switch itself, it's just not going to function because the wiring isn't there. There is a wire missing in the harness/connector that goes to the tail lamp on the '03-'05s (pin 6 on B125). That wire actually goes through some other harnesses for the passenger side door lock sensor, which only allows the button to open the trunk (via the BCM) if the door is unlocked.

Edit: I feel you might be missing a piece of info seeing as you appear to have an '05 sedan.... The '03-'05 coupes do not have an external trunk button. It's either the switch inside the car or the key fob.

 

My 2006 coupe does not have i-key, I do have the tail light trunk opener. @b73 what year is your vehicle?

 

my car is 05 i only have the keyless entry onfob no auto start or that fancy stuff and i guess with my luck i would have to bye the whole light but i did post a couple of other things and i dont know if there connected
hazzards dont work but turn signals do
cruise light stays on cc dont work

 

Why are you looking to buy a whole light?