Intermittant Key Fob response

[Lakotah]

The key fob for my 99' C-5 unlocks the doors intermittently. I bought a new GM key fob with a new battery, programed it but still the lock/unlock works when it wants to no matter how close or where I'm standing. Hmmmmmmm. I had this problem a while back but it seemed to clear up on it's own. This time thought it just continues to be annoying. Any suggestions anyone?

 

[timfitz63]

What you're describing kind-of sounds like the proximity lock/unlock feature that GM provided with the early-model (pre-2000, I think) C5's. When the fob is in the "PASSIVE" mode (set via an ON/OFF slider switch on the front of the key fob) the car will [theoretically] lock or unlock the doors, depending on how closely the fob is located to the vehicle, without anyone touching a button on the fob. Why did only the early-model C5's have this feature? Probably because the system was utter rubbish. Recently this system on my '98 coupe started responding erratically to the fob, locking and unlocking the doors despite the fob remaining in immediate proximity of the vehicle. It actually managed to lock the keys (fob and all) inside my '98 coupe -- then wouldn't unlock the doors again. Brilliant... :eyerole

It's conceivable that a low battery in the fob could be responsible for the erratic behavior I experienced, but I didn't try swapping mine out to see if that improved the situation; I just switched the fob's "PASSIVE" setting to "OFF" and plan to leave it there forevermore. If your fob is in the "PASSIVE" setting, I suggest moving the slider switch to the "OFF" position to see if that helps; with "PASSIVE" mode "OFF" the fob functions like every other remote key fob, requiring a deliberate button push to lock/unlock the doors.

 

[Lakotah]

No Passive switch

What you're describing kind-of sounds like the proximity lock/unlock feature that GM provided with the early-model (pre-2000, I think) C5's. When the fob is in the "PASSIVE" mode (set via an ON/OFF slider switch on the front of the key fob) the car will [theoretically] lock or unlock the doors, depending on how closely the fob is located to the vehicle, without anyone touching a button on the fob. Why did only the early-model C5's have this feature? Probably because the system was utter rubbish. Recently this system on my '98 coupe started responding erratically to the fob, locking and unlocking the doors despite the fob remaining in immediate proximity of the vehicle. It actually managed to lock the keys (fob and all) inside my '98 coupe -- then wouldn't unlock the doors again. Brilliant... :eyerole

It's conceivable that a low battery in the fob could be responsible for the erratic behavior I experienced, but I didn't try swapping mine out to see if that improved the situation; I just switched the fob's "PASSIVE" setting to "OFF" and plan to leave it there forevermore. If your fob is in the "PASSIVE" setting, I suggest moving the slider switch to the "OFF" position to see if that helps; with "PASSIVE" mode "OFF" the fob functions like every other remote key fob, requiring a deliberate button push to lock/unlock the doors.

Thanks for getting back to me but I have no passive switch on my key fob and I installed a new battery in it when I first bought it a few weeks ago. Guess I better check the receiver for the fob that sits just behind the drivers seat I believe. I don't know, maybe there's a loose connection there or something. Other than that maybe someone that's had the same problem will eventually read this post.

 

[timfitz63]

Hmm. Well, I'm not completely certain of this, but the newer fobs (without the "PASSIVE" feature) may not be compatible with the older system. That right there could be the problem, at least with the new fob. Do your older fobs have the "PASSIVE" feature?

 

[Lakotah]

Yeah, could be

Hmm. Well, I'm not completely certain of this, but the newer fobs (without the "PASSIVE" feature) may not be compatible with the older system. That right there could be the problem, at least with the new fob. Do your older fobs have the "PASSIVE" feature?

You know maybe your right about that. My original ones had the passive switch and years ago they failed so I bought a replacement (without the passive switch)at a chevy dealer believing what they said it was the right replacement. But you know it seems as though the new one worked OK. But thinking back it wasn't a 100% all the time. Eventually now it's only working after pushing the unlock button a number of times and sometimes it works the first time. Like I said it's intermittent. I don't know their quite pricy, so for now I guess maybe I'll put up with it for a while unless maybe the receiver has a problem and fails in time. Anyways thanks for your input. Anything else you can think of?

 

[timfitz63]

No worries! I think that's about all it could be: either the newer fobs are not fully compatible or the system is glitching. Hope it's not the latter; operating second-hand modules are nearly impossible to find, and after the GM bankruptcy there's no NOS at Chevy dealers for just about all C5 electronic parts...

Not sure why you gave up on the older fobs, but you might try one of those again. Replacement versions of older style fobs are difficult to find as well.

 

[Lakotah]

cold solder

No worries! I think that's about all it could be: either the newer fobs are not fully compatible or the system is glitching. Hope it's not the latter; operating second-hand modules are nearly impossible to find, and after the GM bankruptcy there's no NOS at Chevy dealers for just about all C5 electronic parts...

Not sure why you gave up on the older fobs, but you might try one of those again. Replacement versions of older style fobs are difficult to find as well.

The other two original fobs stopped working and from what I understood at the time was that some parts of in the fob were cold soldered (?) and it becomes a loose connection. I still have one so maybe just for curiosity sake I'll try to program it as fob #2 and see what happens. Over the years I've my share of electrical problems with my C-5 mostly related to bad grounds everywhere. Cleaning them made a lot of problems go away including trouble codes on the information center. I've probably spent 8k or so this past couple of years keeping my C-5 in good condition and it's getting to the point I'm wondering what else can go wrong.

 

[timfitz63]

The other two original fobs stopped working and from what I understood at the time was that some parts of in the fob were cold soldered (?) and it becomes a loose connection. I still have one so maybe just for curiosity sake I'll try to program it as fob #2 and see what happens. Over the years I've my share of electrical problems with my C-5 mostly related to bad grounds everywhere. Cleaning them made a lot of problems go away including trouble codes on the information center. I've probably spent 8k or so this past couple of years keeping my C-5 in good condition and it's getting to the point I'm wondering what else can go wrong.

Interesting. Yeah, it seems many of the GM fobs during this period eventually stop working. If someone handy with IC boards could isolate the problem, folks could perhaps repair the affected soldering joints.

I've managed to avoid any electrical issues with my C5's, but from what I understand the bulk of them can be traced to grounding issues.

Good luck resurrecting one of the old fobs! Let us know how it goes!

 

[Lakotah]

Wouldn't you know

Interesting. Yeah, it seems many of the GM fobs during this period eventually stop working. If someone handy with IC boards could isolate the problem, folks could perhaps repair the affected soldering joints.

I've managed to avoid any electrical issues with my C5's, but from what I understand the bulk of them can be traced to grounding issues.

Good luck resurrecting one of the old fobs! Let us know how it goes!

Who woulda thought that one of my original key fobs that I had sittin on my work bench for many years, after dusting it off, putting in a new battery (which stopped working many years ago) has decided to start working again. Hmmmmm. Stranger things have happened but I guess electrical stuff does that. I don't know how long it's gonna last but I'll give it try. Curiously though a thought just crossed my mind, I wonder if it not working had anything to do with all the electrical issue's I was having. I was having a lot of codes come up on the DIC. You know, along with the chimes coming up telling me I had some bogus problems with BCM's and the like. Windows did not work. Just a bunch of weird stuff. And all the time it was a grounding issue. What a pain in the neck that was. Anyway looking around I found an original key fob on E-Bay. It looks new and the guy appears to have a good report per E-Bay. And he says it works and returnable. Kinda puts me between a rock and a hard place. Should I take a chance on it or hope the one I have never gives up. Or just forget about it and use my key all the time. This early electronic stuff, I don't know. Made in different places around the world then all the components assembled together here.

 

[timfitz63]

Who woulda thought that one of my original key fobs that I had sittin on my work bench for many years, after dusting it off, putting in a new battery (which stopped working many years ago) has decided to start working again. Hmmmmm. Stranger things have happened but I guess electrical stuff does that. I don't know how long it's gonna last but I'll give it try. Curiously though a thought just crossed my mind, I wonder if it not working had anything to do with all the electrical issue's I was having. I was having a lot of codes come up on the DIC. You know, along with the chimes coming up telling me I had some bogus problems with BCM's and the like. Windows did not work. Just a bunch of weird stuff. And all the time it was a grounding issue. What a pain in the neck that was. Anyway looking around I found an original key fob on E-Bay. It looks new and the guy appears to have a good report per E-Bay. And he says it works and returnable. Kinda puts me between a rock and a hard place. Should I take a chance on it or hope the one I have never gives up. Or just forget about it and use my key all the time. This early electronic stuff, I don't know. Made in different places around the world then all the components assembled together here.

Cool! Yeah, hard to say at this point, but the perceived problems with the fob could have just been grounding issues. Strange things happen on the C5 when there are power issues. I think you'll have better luck with the old-style fobs now that the grounds are all good. Let us know!

 

[Lakotah]

Works OK so far

Cool! Yeah, hard to say at this point, but the perceived problems with the fob could have just been grounding issues. Strange things happen on the C5 when there are power issues. I think you'll have better luck with the old-style fobs now that the grounds are all good. Let us know!

Got my new (well sort of new) key fob with the passive switch and it works fine. Now I've got two that I can rely on for now. Actually the one I just got looks new like it had hardly been used. Whew! Now that I have that fixed a new problem has arose. Setting the drivers seat memory button has a mind of it's own. After starting my C-5 the seat goes to any random position it wants. Of course I've got to re-adjust it before I start out and pushing the set now button time after time has no effect. I have to say this is a entirely new problem. I'll start a new thread on that. Thanks for your in-put Tim.

 

[timfitz63]

Got my new (well sort of new) key fob with the passive switch and it works fine. Now I've got two that I can rely on for now. Actually the one I just got looks new like it had hardly been used. Whew! Now that I have that fixed a new problem has arose. Setting the drivers seat memory button has a mind of it's own. After starting my C-5 the seat goes to any random position it wants. Of course I've got to re-adjust it before I start out and pushing the set now button time after time has no effect. I have to say this is a entirely new problem. I'll start a new thread on that. Thanks for your in-put Tim.

Glad you got it sorted out!

I don't have a solid answer on the seat; that's an odd one I've not heard before. Electrical problems are often hard to track down... Good luck with that one!