Hey, I have a '03 MCS with 50,000 miles on it, and yesterday i just noticed that my car will not lock from the outside. Meaning when i use my fob or put the key in my door to lock it, the car locks and automatically unlocks. Anybody else had these problems?

Also, this just happened recently, anytime my driver door is open i get that familiar chime that happens when you leave your lights on, however my lights aren't on and the keys aren't in the ignition. Any ideas?

Thanks in advance,
Austin

 

Any forewarning of a problem before this happened ?

Only issue I had was all of a sudden, my fobs stopped working. Dealer had to diagnose and eventally retrieve old codes from the system and reprogram them in.

 

No, there was no forewarning, unless the door chime counted as a warning (I think of it more as an annoyance). Did your fobs not work at all? Because my car still recieves the signal and locks, it just automatically unlocks again.

 

A bad battery can cause some weird things to happen. How old is your battery?

 

That really is a good question, it came with the car when we bought it and they never told us. Any idea what brand the stock battery is?

I did unplug the battery for 5 minutes to reset the BCU... no success

 

My 5 year old original battery was doing funky things with the windows and clock. Replacement solved the probs.

 

Don't get an OEM battery> The dealer wants way to much money for it. You can get a battery that fits from most manufacturers/shops.

 

Yes and no. You might want to check these threads before buying a new battery so that you get one that does fit.

www.northamericanmotoring.com/forums/stock-problems-issues/102287-replacement-battery-options-for-mcs.html

www.northamericanmotoring.com/forums/stock-problems-issues/105283-replacement-battery-options-for-mc.html

 

Not sure what you meant with the links. My statement stands. The OEM is way expensive and doesn't have a decent warranty to boot.

Lot's of great alternatives in the MCS thread tho.....

 

Having the same problem. Cruise is inop as well.

Any luck correcting it? (My battery is new.)

 

Now I'm having the same problem on my 2007 MCS. Doors unlock after locking. Sometimes immediately after but its totally random when it will unlock on its own.

Is it a faulty door lock mechanism causing the BCU to send out the wrong signals?

 

It turned out to be the fuse for the alarm system. Just that simple!

 

But I don't have an alarm system.

 

I dont either not sure what shares the fuse.

 

What was the fuse number on the panel cover's chart ?

 

Er - let me check. Can't remember.

 

Thanks, made the mistake of tapping the alarm fuse for a power source then changed my mind and pulled the tap out. Ended up with doors not locking, windshield washers spurting every time key was turned on or off.