1999 QX4 Door lock buttons only work with ignition on. Security and opener not working

[Elway358]

Hi, looking for some help on a problem I have with my 1999 QX4. I just had the AC system replaced 2 days ago and today after driving it for the first time since, my gf comes home and says something is wrong with the locks and that she couldn't open the garage door with the built in transmitter.

Sure enough, for some reason the door lock buttons will only work now with the ignition key turned on. Also I tried reprogramming the garage door opener per the manual like I have done before and got nothing. Any ideas what could be going on here? I will call the guys that did my AC work tomorrow and let em know what's going on but I know it will be a drop it off and wait deal which I really am not looking to do yet again.

Hoping you guys/gals may have some things I can check without putting it taking it back to the garage. Thanks very much for any help

[Elway358]

So after doing some more looking, I also noticed the security light wasn't flashing at all. Testing it some and I now realize it isn't working either. Seems like this is all related but not sure how. The vehicle starts fine and everything else works with the ignition on/vehicle running.

I've never had the keyfob for the vehicle since owning it but have spare keys and the ones I have been using since I got it a few years back that Ive never had any issues with. Ive tried "resetting" the security using methods Ive seen online but nothing changes. Thanks again if anyone has any ideas.

[04pathse]

Well, I could be wrong but I believe all of those are controlled by the "smart entrance control unit" located under the dash, near the interior fuse box.

Maybe check to make sure the harness connector is plugged in to the smart entrance control unit ( I believe it is gold in color).

Also check fuses and make sure relays are in place...

You can look here at the FSM for more info...

The SECU is covered starting on page 250

http://www.nicoclub.com/service-manual?fsm=QX4/1999/EL

[Elway358]

I have a feeling you're right about it being that control unit. I poked around today as much as I could stand it in this freakin heat and also realized my interior lights or chime don't work which seem to be controlled in part by that unit as well. I checked all the fuses inside and out and all the visible connections I could see and saw nothing wrong.

I have a multimeter to check some voltage and continuity but realized its at a second house we have and would be as much of a hassle to go and get as it would be to take this thing back to the shop where this problem arose. I really appreciate your help with this though as I believe you've pointed me in the right direction and most certainly pointed out some good reference material. Thanks a lot

[Elway358]

So just wanted to give an update on what was wrong here. It was the most basic thing it could have been...a fuse >.<

Turns out the mechanic who did my AC work also found that it blew the fuse when the compressor froze up so he decided to just pull an "extra" one from a slot labeled ELEC(B). Since what that fuse controlled was such random things, he thought everything was working fine and that that fuse was "extra" in his own words. LOL.

Funny thing is I had checked all the fuses this past weekend and actually saw that empty fuse slot but I couldn't see any contacts in the slot and myself assumed it was a blank slot and didn't even simply try to stick a fuse in it. So yeah, that was the issue thank goodness.

Thanks again for the info and help