Just the past few weeks my 94 Z28 has developed a problem with unlocking the passenger side lock with the stock keyless entry. It is very flaky, sometimes it will work fine, then it won't unlock again. I've already replaced the batteries in the remote, which didn't do much. It lock and unlocks fine with the power switches inside the car, and it will always lock when using the remote.

I've checked the lock itself, it isn't binding or hanging up in any way. Any other things to check other than the keyless entry module is on the way out? I can't think of much else and doing a search didn't turn up much.

 

Did you figure it out? Mine is doing the same thing. Will only unlock pass side every once in a while.

 

I have the exact same symptoms

 

I dont know if they change for 99 (since all 3 are 94-95). I think i remember the keyless is in the bcm. The pass output might be going bad. If you have progressive door locks (push once for driver, twice for pass) you could just bypass it to unlock both with one push. I did this years ago so dont remember everthing and might be different.

 

Sorry, haven't had a chance to play with it yet, I've been over in Ohio on business for the past few weeks. I've done a little research, but other than the keyless entry module going bad, I'm not finding much else. When I take it apart I'll probably just end up wiring it so it unlocks at the same time the drivers side does. The progressive lock feature has never been much use anyway.

 

Seems to be a theme here LOL.Having the same problem.Mine the door switch works fine,but the key fob won't unlock the passenger side door at all any more.I thought it might be because of the fact that I had an aftermarket fob.So I purchaced factory one and tried it.No go on that attempt.So i will be watching this thread with intrest a keep looking for a fix.

 

Finally got around to checking it out, I might have a fix that doesn't involve replacement. I don't know if this will work on anything other than a 94 Z28 with keyless entry, but others with different years can update if they find anything new.

The keyless entry module is on the passenger side behind the kick panel. It's a black box with 2 connectors going into it. One controls the doors, the other controls the hatch. If you get the module out (removing both connectors helps a lot) and open it up, you will see a small potentiometer that you can adjust. Try moving the pot to different positions and see if it improves your keyless entry response. I moved mine left about 1/4 turn from the position it was in and there was a huge difference. The doors unlocked will better response than before, as well as the passenger side door unlocking every time I hit the button twice.

I also tried moving it in the opposite direction and got the opposite affect. Both doors stopped working and would only work for a little bit sometimes. Rarely, if ever, did the passenger side door unlock if I got the driver door unlocked. The hatch stopped working as well.

I believe that what is happening is a lack of voltage being applied to the 3 relays that open and close the doors, causing them to stick open. Adjusting the potentiometer either lowered or raised the voltage, resulting in either the locks not working or all working correctly again. Over time the module has probably degraded somewhat (this is a 16 year old car now, after all) but not so much that it doesn't work at all. A small increase in voltage got everything working again.

I'll make sure to keep updates on this thead if anything new occurs. If anyone else has anymore info, please post it as well.

 

wow, all the wiring I know about these cars and I never even considered opening it up. Good to know

 

Another update: Unfortunately, it seems to be a short lived fix on my car. It was back to not opening the passenger side lock again. The driver side and hatch still work fine, though.

I'm going to see if I can get replacement relays, desolder the old ones, and put the new ones in. I'll update if I can get ahold of them and if it works.

 

Well, I've had no luck finding replacement relays and no real luck finding a replacement module. The passenger side unlock feature is still flaky and the range is almost zero as well. I think I'm just going to replace the stock system with an alarm with keyless entry. It probably won't cost me any more than finding a replacement module at this point.