only driver's door unlocks '06 elantra

The car is a 2006 Hyundai Elantra GLS which has a CoolStart RS-1304.DPII remote starter installed. It used to lock/unlock all doors at once, and now will only unlock the driver's door. The door button also will not unlock the other doors. The doors all still lock at the same time with the remote and the door buttons. It still will not unlock all doors after multiple presses. I am assuming the problem is with the starter and not the car, but I may be wrong. I took a look at the programming procedure for the remote starter and I am wondering if the option for "double unlock pulse" might be what I am looking for. Single is default. I tried to test my idea, but I couldn't figure out how to get into programming mode. I am also not sure because it used to unlock all doors. The battery has not been drained or disconnected (as far as I know), so I don't know how it would reset back to default if that is the case. Thanks for any help.

I think you may eithier have a blown fuse or a damaged relay push the lock/unlock switch on the door and you should hear a relay clicking as you do this. It should be somewhere around the fuse box I believe and from there you should be able to swap the unlock relay with the lock relay which will be able to tell you if your relay is damaged

Did you install it, or a shop? If a shop did it, will they fix it under warranty? Do you know how/where the doorlocks are hooked up? That's the first thing. I think there are some relays on the back of the fuse box.......the installer may have chosen to unplug the relay, wrap a wire around the appropriate contact on the relay, and then plug it back in. So, if that's the case, there's a possiblity that the relay to unlock the other three doors has come partially or completely unplugged. Just a possibility, but worth checking. Regardless, the first step would probably be to follow the lock and unlock outputs from the remote starter, and find out where they're connected to in the car.

Thanks for the replies. I will look more in depth at how the locks are hooked up and where the relays are located. It is not my car, but I have access to look at it on most days, so I will post back as soon as I get a chance.

I got some time to look into the problem more today. First, the remote starter interfaces with the locks by two wires for locking and unlocking. They are teed off the factory wires which are at 12v, they ground when locking and unlocking the doors. The connections are solid and there seems to be no problem there. Because the connections are just teed off, it doesn't seem like it should disrupt the stock operation of the locks. To make things more interesting, on the passenger side door when the lock is manually opened all doors unlock (there is no button for lock/unlock on the passenger door). The same thing happens with the key in the passenger door, all doors will unlock when turned. The key in the drivers door only unlocks that one door, even when turned multiple times to unlock. So now I am lost as to if the problem is with the remote starter or something on the car itself.

if the switch doesn't work then its the car. more then likely you have an issue with second unlock relay when you use the seitch listen for the relays clicking and thats where you want to look. I'm fairly certain that the relays are behind the fuse box, but I've also seen them in the center console but I beleive thats only on older elantras

I was starting to think that the problem is with the car as well, so that is good to hear. I have located one unlock relay on the fusebox, which has a 5 pin connection to it. It clicks when I press unlock in all cases, so it seems like it probably only corresponds to the drivers door, but I have since found that there are more locking related components behind the AC controls, so I will check those too. The vehicle already has power locks so no actuators are needed. It used to work correctly, then it started having trouble, and now it doesn't work at all. Those are the wires that were used though.

I wanted to post back finally about fixing the problem, maybe the info will help someone else at some point. The issue was with the door lock/unlock relay unit. It is located behind the climate control unit. It is a black box with a single bolt off towards the passenger side. I pulled it out and tested it with a test procedure from hmaservice.com You can sign up for free and it will give you access to all Hyundai repair info and schematics. When testing, it clicked for both the lock and unlock signal, but the switch did not actually make contact for the unlock relay. Once I determined it was not working, I popped the box open to look inside. There was one relay for lock and one for unlock. They are soldered on the board so it would not have been worth the time to switch or to replace just the relay. I did put the old one back together, and I must have shaken it around enough to get the relay making contact again, at least temporarily. But, it was still working intermittently so I just replaced it. This part is around $30 new from an online genuine parts store, but I got a used one for $10 at a junkyard. It is possible it would have been under the warranty, but I didn't even bother to check.