Keyless entry
06-13-2010, 10:37 AM
#1
MBWorld Fanatic!
Thread Starter
Keyless entry
When I first got my Cab one of the very first things on the list of must-do's was add keyless entry. I wanted a system of known compatibility with the vacuum lock system and one that had the newer MB flip style key fobs. So I picked up an Aussi-Max system off of ebay. This system is promoted as "plug and play" but it is really un-plug and play - if installed as delivered, you lose the ability to use your trunk with a key!
This was unacceptable, but I realized that there are some big advantages with installation via the trunk actuator circuit over the method recommended in the posts I reviewed which involves installing at the vacuum pump controller under the seat. First, power and ground are both available in the three-wire trunk actuator bundle (Aussi-Max has totally missed this fact which would have eliminated the need for separate power wiring via the trunk light, thus making their system completely un-plug and play). Second, as far as I can tell, this method will arm/disarm the factory alarm on all W124's except the wagon with no additional relays or wiring. Lastly, the receiver antenna is now up high near the tail lights giving increased range.
In order to keep my trunk use via the key I had to cut into the actuator wiring not unlike the under the seat method. I checked out the internal design of the Aussi-Max controller and realized the each channel is simply and SPDT relay output. With this I was able to re-configure things and connect the system as shown in the attached schematic. Note that power/ground are picked up right off the actuator harness, making for a neat and tidy installation (I used solder + heatshrink for making the connections, but there are other methods).
Anyway, I hadn't seen this approach posted anywhere, so I though I would post my experience.
- FD
This was unacceptable, but I realized that there are some big advantages with installation via the trunk actuator circuit over the method recommended in the posts I reviewed which involves installing at the vacuum pump controller under the seat. First, power and ground are both available in the three-wire trunk actuator bundle (Aussi-Max has totally missed this fact which would have eliminated the need for separate power wiring via the trunk light, thus making their system completely un-plug and play). Second, as far as I can tell, this method will arm/disarm the factory alarm on all W124's except the wagon with no additional relays or wiring. Lastly, the receiver antenna is now up high near the tail lights giving increased range.
In order to keep my trunk use via the key I had to cut into the actuator wiring not unlike the under the seat method. I checked out the internal design of the Aussi-Max controller and realized the each channel is simply and SPDT relay output. With this I was able to re-configure things and connect the system as shown in the attached schematic. Note that power/ground are picked up right off the actuator harness, making for a neat and tidy installation (I used solder + heatshrink for making the connections, but there are other methods).
Anyway, I hadn't seen this approach posted anywhere, so I though I would post my experience.
- FD
06-17-2010, 12:16 PM
#2
Senior Member
Floobydust,
thanks for this research. I have been interested in keyless for some time on my 94 E420. The problems i have read about all seem to be related to the alarm malfunctioning in various ways. I have always thought that the door or trunk lock needed to be physically "turned" in order for the alarm function to remain correct.
Your layout appears to send the open and close signal to the alarm control box. however, no lock cylinder wil have rotated - correct?
do all car functions and alarm functions operate without issue with this configuration?
really, this is a big deal if it works correctly. thanks again......
thanks for this research. I have been interested in keyless for some time on my 94 E420. The problems i have read about all seem to be related to the alarm malfunctioning in various ways. I have always thought that the door or trunk lock needed to be physically "turned" in order for the alarm function to remain correct.
Your layout appears to send the open and close signal to the alarm control box. however, no lock cylinder wil have rotated - correct?
do all car functions and alarm functions operate without issue with this configuration?
really, this is a big deal if it works correctly. thanks again......
06-17-2010, 02:56 PM
#3
Member
I have the Assie in an E320, trunk mounted, no issues. I'm courious...how does your unit stop mechanical operation with the key? Or are you saying that the trunk key lock will now not operate the rest of the central locking system?
06-18-2010, 11:23 AM
#4
MBWorld Fanatic!
Thread Starter
kafklatsch & Hano -
The performance of the system has been flawless. The doors/trunk can be properly locked/armed and unlocked/disarmed using the key from all three locks as well as locked/armed and unlocked/disarmed using the remote keyfob. There have been no false alarms or "race states" with this connection.
I have read about various alarm issues as well. I think that many of these stem from the fact that MB changed the way that the alarm is armed/disarmed over the years. Early cars used an electrical trigger right off the off the vacuum lock/unlock switch on the the doors. To ensure that the alarm would only arm/disarm only when the key was used, a hysteresis or mechanical clutch was built into the lock & switch mechanism. Later cars used a separate arm/disarm switch for the doors to accomplish the same thing, therefore later cars may not arm/disarm the system properly as the mechanical rotation induced by the vacuum actuators is not sufficient to trigger the separate switches due to the built in hysteresis. This makes sense because MB wanted only the key to be able to arm/disarm the alarm (the alarm would be pretty useless otherwise!). The differences in wiring and the reliance on a pneumo-mechanical link in some cases is why, I believe, there are troubles with the "under the seat" method.
But all cars (except the wagon) in all years took the alram/disarm signal directly from the 3-wire trunk actuator. So it makes sense that this is the point where you want to "tap" into the system. By electrically emulating the "key" here, you guarantee that all the other systems will work as designed.
The issue with the standard Aussi-Max system is that they disconnect the contacts that are part of the trunk actuator. While this does not affect operation with the keyless remote, locking the car with either the key in either door or with the keyless remote and the unlocking the trunk with the key will cause the alarm to go off. Conversely, locking the trunk will not lock the car or arm the alarm. With the Aussi system, to avoid these glitches, you must always used the remote. You lose the ability to activate/deactivate the rest of the system from the trunk location with the key.
There is one caveat I should point out. If you lock/unlock with the key and then try to do the opposite from the keyfob, the Aussi-Max will be out of sync with the mechanical state of the system. To re-sync, simply press the 1 then 2 button or 2 then 1 depending on whether the car is locked or unlock. This is an issue with the design of the AussiMax controller, not the way it is connected. If the AussiMax simply provided contact closure upon button press there would never be an issue. In practice, the 1 -2 button press becomes automatic in those rare instances when the Aussi system loses sync. Again, this does not cause false alarms, etc.
So, given all of this, I arrived at the connection shown in my schematic. It works great for me and I hope it will become a helpful method for others as well.
- FD
The performance of the system has been flawless. The doors/trunk can be properly locked/armed and unlocked/disarmed using the key from all three locks as well as locked/armed and unlocked/disarmed using the remote keyfob. There have been no false alarms or "race states" with this connection.
I have read about various alarm issues as well. I think that many of these stem from the fact that MB changed the way that the alarm is armed/disarmed over the years. Early cars used an electrical trigger right off the off the vacuum lock/unlock switch on the the doors. To ensure that the alarm would only arm/disarm only when the key was used, a hysteresis or mechanical clutch was built into the lock & switch mechanism. Later cars used a separate arm/disarm switch for the doors to accomplish the same thing, therefore later cars may not arm/disarm the system properly as the mechanical rotation induced by the vacuum actuators is not sufficient to trigger the separate switches due to the built in hysteresis. This makes sense because MB wanted only the key to be able to arm/disarm the alarm (the alarm would be pretty useless otherwise!). The differences in wiring and the reliance on a pneumo-mechanical link in some cases is why, I believe, there are troubles with the "under the seat" method.
But all cars (except the wagon) in all years took the alram/disarm signal directly from the 3-wire trunk actuator. So it makes sense that this is the point where you want to "tap" into the system. By electrically emulating the "key" here, you guarantee that all the other systems will work as designed.
The issue with the standard Aussi-Max system is that they disconnect the contacts that are part of the trunk actuator. While this does not affect operation with the keyless remote, locking the car with either the key in either door or with the keyless remote and the unlocking the trunk with the key will cause the alarm to go off. Conversely, locking the trunk will not lock the car or arm the alarm. With the Aussi system, to avoid these glitches, you must always used the remote. You lose the ability to activate/deactivate the rest of the system from the trunk location with the key.
There is one caveat I should point out. If you lock/unlock with the key and then try to do the opposite from the keyfob, the Aussi-Max will be out of sync with the mechanical state of the system. To re-sync, simply press the 1 then 2 button or 2 then 1 depending on whether the car is locked or unlock. This is an issue with the design of the AussiMax controller, not the way it is connected. If the AussiMax simply provided contact closure upon button press there would never be an issue. In practice, the 1 -2 button press becomes automatic in those rare instances when the Aussi system loses sync. Again, this does not cause false alarms, etc.
So, given all of this, I arrived at the connection shown in my schematic. It works great for me and I hope it will become a helpful method for others as well.
- FD
06-18-2010, 01:08 PM
#5
Member
Appreciate the information! I have a statistical sample of two(!) keyless entries on W124, one Aussie (@trunk) and one another brand (@ vacuum pump). I'll keep your schematic in mind for the next one (3 left to do).
06-18-2010, 08:06 PM
#6
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500E Signal Rot
I have installed a keyless entry system and also tied it into the factory security system. Data is at www.2phast.com/500e under stereo/alarm upgrades.
08-20-2010, 06:05 AM
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Mercedes C-class
Well, I have installed the Key less security system in new Mercedes car and good to know the informative post related to the Key less entry. This post had helped me in understanding the essential features of the key less security systems.
