I have the following keyless entry for my '91 300CE and I'm trying to just wire it into the trunk actuator. I only want the lock/unlock function...do I need the relays for this? I have 3 wires (red/white - 12v constant, brown - ground, and yellow - 12v when unlocked, 0v when doors are locked) to the trunk actuator and 4 wires from the keyless module (red - constant 12v input, black - to negative ground, blue - output #3, and green - output #4). See attached PDF...thanks.

ryan

Attached Files

REC-43T-1.pdf (53.3 KB, 797 views)

__________________
RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

You will need two relays. Check out this link for some more information:

http://www.peachparts.com/Wikka/W124Keyless

J. M. van Swaay

__________________
1994 E320 Wagon, 230,000 miles
1995 E320 Sedan, 106,000 miles
1994 E500 Sedan, 79,000 miles

Yes, I have read thru that. But, there are several threads that seem to indicate the relays are not necessary if you are just hooking up a lock/unlock system and if the keyless module has a timed delayed release set-up, which this one does.

Thanks for the response.

Ryan

__________________
RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

I am referring to this specific thread - Keyless entry -- W124 - among others.

Check out posts 28 and 29...
ryan

__________________
RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

The only type of output available from the REC43T is a "sink to ground" ie, a ground supply. This ground supply can be used as a direct input to a control module, or it can be used to supply ground to a relay coil thereby activating the relay. This ground sink signal is fairly low amperage so it can only be used to close a relay or as a signal input to a control module. Most MB's require a ground signal for lock, and +12 volt for unlock. It might be possible to wire up the lock circuit without an external relay, but for unlock, you will need to somehow convert the sink to ground to +12volt. If you really want to avoid using a relay, this conversion could be accomplished with a transistor circuit, but not without a fair amount of soldering and circuit fiddling.

I have a REC43T installed in my 95 E320 Sedan. I used one relay for lock, and one relay for unlock. The relays are connected in series into one of the three signal wires. (blue, green, or yellow, doesn't matter which....) When active, the relays just insert a ground for lock and +12 for unlock. In addition to using the ground signals to activate the relays, I also used these same signals as inputs to the convenience control module. The convenience control module inputs arm/disarm the factory alarm, and (and this is really cool) allow you to command the window rollup/rolldown feature as well.

I added a few other bells and whistles--light flash and panic. The light flash takes an additional relay as does the panic. The panic is accomplished by simulating an open door when the factory alarm is armed.

Pretty cool and it can all be done for less than $40.

J. M. van Swaay

__________________
1994 E320 Wagon, 230,000 miles
1995 E320 Sedan, 106,000 miles
1994 E500 Sedan, 79,000 miles

OK, I must be reading the other posts wrong - it sure seems to me that they are describing a way of wiring this up to the trunk actuator w/o relays.

So, where do I get the relays? I'm sure I've come across that info before, but I can't remember where??

ryan

__________________
RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

I love that kit. So simple and straight forward. Just had to use 2 relays.

__________________
CENSORED due to not family friendly words