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DB605
Member
Date registered: May 2015
Location: South FL
Vehicle(s): 99 G500 LWB
Posts: 20
| 99 G500 - door lock / alarm issue.
Greetings
After several searches with different key words, I have not found a post describing a condition like the one I am experiencing, so here it goes.
99 Europa G500 WDB4632411X114585
When I bought the car, both remotes and all door locks and fuel cap locked just fine.
Over time one remote stopped working (I thought from dropping it a few times, but light inside still lights up).
More recently the alarm starting going off randomly, I looked into the common battery failure in the siren behind the headlight in some MBUSA cars but this one doesn’t have that system from what I can tell, I took the headlight off and that part was not there.
Also replaced the hood open sensor near the Air recycle flap in the engine bay. That’s the only sensor I have replaced, haven’t done any of the ones at each door.
Alarm would only go off if I locked the car so started leaving it unlocked. Power locks still worked on all corners.
Now, the power locks died and each door needs to be locked manually. Red/Green indicators still react normal if I try the remote but nothing happens with the locks.
Im thinking one of the lock actuators failed, possibly the drivers side, making all others not work.
Open to any suggestions on the locks and the alarm as well because I think that will still continue to go off even if the power locks come back. |
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Otiswesty
Administrator
Date registered: Jun 2007
Location: Portland, Oregon
Vehicle(s): 463.241, 461.213
Posts: 3014
| RE: 99 G500 - door lock / alarm issue.
There are those door pin switches on all 4 side doors and some of the plastic inside degrades and just need tom replace. They are a common wear item that I have replaced pretty frequently. The cargo door pin switch is very robust and unlikely to be affected.
You should replace the batteries in both your remotes as well for good measure.
Next step would be to repair or replace the Kiekert relay in the electronics box under the hood. Some people have resoldered the circuit board in there if damage. Do a search here, there is some great info on this. I have a spare Kiekert relay that is used but good. I bought one to diagnose a door lock issue that wasn't helped with a new unit. |
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DB605
Member
Date registered: May 2015
Location: South FL
Vehicle(s): 99 G500 LWB
Posts: 20
| Re: 99 G500 - door lock / alarm issue.
Thank you very much for the reply. Will start with the door pin switches!
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paulunm
Veteran
Date registered: Jan 2015
Location: Los Angeles
Vehicle(s): 2000 G500
Posts: 124
| Re: 99 G500 - door lock / alarm issue.
Try hitting the "tow" button before you lock the truck. If that keeps the alarm from sounding, it's your shock/tow sensor that's gone bad. It's under the center console at the front. It's NLA so you can unplug it. |
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Otiswesty
Administrator
Date registered: Jun 2007
Location: Portland, Oregon
Vehicle(s): 463.241, 461.213
Posts: 3014
| RE: 99 G500 - door lock / alarm issue.
That's a great tip. I don't think I have ever used the tow away button and was considering getting rid of it to use the space for something else. |
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DB605
Member
Date registered: May 2015
Location: South FL
Vehicle(s): 99 G500 LWB
Posts: 20
| Re: 99 G500 - door lock / alarm issue.
This is a great idea. When the locks did work but alarm was going off randomly I did try that and it did not seem to stop the alarm sounding after about 20 min of being locked. Will investigate disconnecting it!
Thank you!
Edited by DB605 12/5/2023 8:08 PM
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Braingears
Expert
Date registered: Apr 2006
Location: St Petersburg, FL
Vehicle(s): G320 & ML320
Posts: 1450
| RE: 99 G500 - door lock / alarm issue.
I dealt with this problem for a number of years. It was very embarrassing to randomly go off in front of my house. My workaround was to open the rear door, and then manually lock the front door without activating the alarm. It turned out to be the controller that detects if the truck is getting towed. It was hidden and a pain to get to, although once I unplugged it, the problem went away. |
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paulunm
Veteran
Date registered: Jan 2015
Location: Los Angeles
Vehicle(s): 2000 G500
Posts: 124
| Re: 99 G500 - door lock / alarm issue.
Yes, this is very common on the pre MBUSA (late 90s?) Gs. The Tow Sensor is under the lower section of the center console- up toward the front- basically buried somewhere under the little cubby just in front of the shifter assembly. |
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DB605
Member
Date registered: May 2015
Location: South FL
Vehicle(s): 99 G500 LWB
Posts: 20
| Re: 99 G500 - door lock / alarm issue.
Thanks for all the input. It ended up being the central locking control unit. I had the alarm disabled vis star diagnostics I believe and have not had any further issues. |
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