wiring help needed for keyless entry - PeachParts Mercedes-Benz Forum

240dddd · #1 09-29-2011, 03:33 AM

I am adding keyless entry to my 85 300D. I have an alarm system, two wire door lock actuator and a few relays. The actuator install is straightforward, but my lack of electrical experience is giving me problems in regards to the wiring.

I have a 'ProSecurity K20' system with the following outputs:

I have two relays and am using the following the wiring scenario (in my case green/black and blue/black are being used like green and blue in the diagram):

The system lights up and makes an audible clicking sound when the lock/unlock buttons on the keyfob are pressed, however the door actuator is not doing anything.

Anyone have some suggestions as to what I have done wrong here? Thanks.

RANDY P · #2 09-29-2011, 04:44 AM

when you say "Green and Blue" I assume you mean those wires coming out of the keyless entry, and not the wires going to the actuator? The two wires on the actuator (should be green and blue as well)- one wire goes to one relay at terminal 30, the other goes to the other relay's terminal 30

Terminal 85 on one relay should go to green / black on keyless entry

Terminal 85 on the other relay should go to blue / black

make sure you have constant +12 (all times) going to all terminals labeled 86 and 87 (NOTE- NOT 87A) on both relays. Put a fuse inline before the relays, like a 20A to protect against dead shorts.

87A on both relays are straight to ground- same place you grounded the alarm module.

To test to see if the actuator is bad take the two wires coming out and plug one wire to +12V while you ground the other lead. It will lock and when you reverse the wires it will unlock. Use the battery under hood.

Conversely, if you have the relays connected properly - check for +12V one ONE of the two relays at terminal 30 (same spot where you connect the actuator lines to)- as you lock and unlock one relay will have 12V.

As you unlock, ONE relay will show +12V at 30, the other one will do nothing. As you unlock the OTHER relay will show +12V at 30, and the opposite relay will do nothing.

hope this helps

rjp

RANDY P · #3 09-29-2011, 05:01 AM

One more thing-

I'm not familiar with that alarm, but assuming all is connected correctly, the next thing is to GROUND the Violet and Violet Black (H1/7 and h1/9 wires) on the brain straight to ground.

If I'm reading this correctly, you NEED to ground those two wires, to send a ground signal to Green / Black and Blue / Black--

so, ground the violet and violet / black wires on the brain.

rjp

cypress · #4 09-29-2011, 01:01 PM

Your unit have built in relays already, so no need for external relays for the keyless lock/unlock. You need to tap into either the "green or blue wire" of your car's vacuum operated lock/unlock system. Also you need to program your unit for 3.5 sec pulse.

+12V = to unlock
Gnd = to lock

240dddd · #5 09-29-2011, 01:33 PM

Thanks for the feedback.

@RANDY P - how you describe the connections in your first post is what I have tried. I haven't tried grounding the violet and violet/black lines yet though. i also need to test the actuator to rule out a faulty unit.

@cypress - the 85 300D doesn't have any built in actuators for the central locking. You have to add an aftermarket actuator to the driver door lock. Unlocking/Locking the driver door is what signals the vacuum system to unlock/lock the rest of the doors.

However, i did read in the manual that the system has built in relays, so I have tried connecting the Green/Black and Blue/Black wires from the brain directly to the aftermarket actuator, but that hasn't worked either.

cypress · #6 09-29-2011, 02:30 PM

I'm not familiar with the "D", but I assume it's the same as the "E".

Do you now have central locking?
That is, does locking your driver's door...locks the rest of the doors, as well as the trunk & gas flap?

If it does, than you have all the actuators, all you need to just hook it up & don't need anything else.

240dddd · #7 09-29-2011, 02:38 PM

The central locking system on the 300D is completely vacuum, i.e. there is no wires to tap into. All of the doors except the driver doors have vacuum actuators that are actuated when the drivers door is manually locked or unlocked. Hence I have to figure out how to drive an aftermarket actuator to lock/unlock the driver door.

cypress · #8 09-29-2011, 05:28 PM

I don't own a diesel or anything to back this up.

BUT I can't believe your central locking/unlocking is controlled via your engine's mechanical vacuum pump.

Can you lock/unlock all doors with engine off?
If yes, than there must be a separate vacuum pump for this. Check under your rear seat, if there is one....it will be there.

You can get at the wires at the pump, pass kick panel, driver kick panel.

ah-kay · #9 09-29-2011, 06:25 PM

I installed Keyless remote in my 83 300D 3 years ago. I am not sure about how 85 works but I believe it should be very similar.

You need to add an actuator to control the vacuum switch inside the driver's door. The system I bought off eBay is a cheapo and simple. It has all the relays inside the control box, no external relay is needed. This is what I suspect you need to do:

1) Hook up the actuator to the vacuum switch which move the vacuum switch in lock or unlock position.
2) Set the control box to pneumatic mode to give it more actuation time.
3) Find a configuration in the instruction manual which gives you 2 output wires, say A and B to wire them to the actuator ( 2 wires model, some model has more ).
4) When in lock, it gives A = 12V, B = 0V locking pulse. Actuator goes up.
5) When in unlock, it gives A = 0V and B = 12V unlocking pulse. Actuator goes down.
6) You need to wire a feedback to the control unit ( Door Open+ or Door Open- ) to indicate door open. The door switch to actuate the courtesy light would do.

That is all there to it. You can hook everything on the table to make sure it functions as above before installing it.

Good luck.

240dddd · #10 09-29-2011, 07:14 PM

Thanks ah-kay.

@cypress - the 300D has a vacuum reservoir tank that allows door locks to function when the car is off.

240dddd · #11 09-30-2011, 02:10 PM

Last night I powered up the brain and reprogrammed it to use the 3.5 second pulse and then attached the H1/5 and the H1/8 wires (using the chart in the first post) to the actuator. But that did not work.

I tested the actuator and it does function.

Next step, rewire everything to the relays and try that again now that it is programmed to use the 3.5 second pulse.

Yak · #12 09-30-2011, 08:42 PM

I'm a bit out of my depth of experience, but I think the 3.5 pulse is meant to apply to cars that use an electric vacuum pump. It needs to the longer pulse to run the pump to build vacuum. The vacuum lock switch on the door needs the extra actuator. That's the M in the drawing. 3.5 on a motor may be overkill. It may not matter overall, but maybe not needed.

The actuator/motor appears to always get +12 on the blue and the green lines into the M (assuming the changeover relays are in their resting state at pin 87 = +12v).

I assume you're using the H1/5 grn/blk lock common output wire as the input to the relay with Green (-) lock wire. That setup would require that wire to "go low" or go to ground to trip the changeover relay. (Difference between 85 and 86 = 12 v, relay trips and goes from 87 @ +12 to 87A @ ground. Motor sees +12v on blue and ground on green and actuates. The motor moves the vacuum switch in the drivers door, then the vacuum system does it's thing). The opposite happens with unlock and blue.

You may want to isolate the setup one relay at a time: does the lock relay (green) click when you lock? Does the unlock NOT click when you press lock? And vice versa. If the relays function properly, then you're halfway there.

Double check you've got your 85, 86, 87, 87A and 30 properly identified and connected.

Then verify the 87, 87A and 30 voltages: in lock, the green 30 should be ground and the blue 30 +12v; in unlock, vice versa. In normal, both 30's should be +12v.

ah-kay · #13 09-30-2011, 10:45 PM

I am not familiar with your control box but I think it is wrong. H1/5 is lock common OUTPUT, H1/8 is unlock common OUTPUT. I believe these 2 pulses are used for cars with EXISTING button control at the driver door. You hook these signal to the switch. You cannot do it with vacuum control MBZ.

If the control box does not come with internal relay for pneumatic configuration then you need to make your own similar to the 2nd diagram. Basically you need 2 wires to connect to the actuator. The principle is similar to control the motor in the power window, only the box gives it a pulse instead of holding the up/down button for 10 seconds to open/close the window.

240dddd · #14 10-05-2011, 04:38 PM

Randy P wins*. Once the violet/violet black wire was grounded it started working as expected. Awesome, thanks!

* not an actual contest

RANDY P · #15 10-06-2011, 12:01 AM

Quote:

Originally Posted by 240dddd

Randy P wins*. Once the violet/violet black wire was grounded it started working as expected. Awesome, thanks!

* not an actual contest

Cool news

Well- to be honest I grew up in Renton /Seattle and I used to be a key (mgr) for several car stereo shops, including a Car Toys way back many moons ago. I'm a ringer.

rjp