Your 12volt remote 2-channel receiver will get power from the Red and Brown wires mentioned above.

The best (fail safe and break-before-make) way to wire a 2-channel 2-relay remote receiver to the car Yellow wire is as follows:

Suppose channel 1 relay 1 is for "Lock", and channel 2 is for "unlock" connect as follows:

Relay 1 Normally Closed terminal - not connected to anything
Relay 1 Normally Open terminal - connected to GROUND
Relay 1 Wiper arm terminal - connected to Relay 2 Normally Closed terminal

Relay 2 Normally Closed terminal - connected to Relay 1 Wiper arm
Relay 2 Normally Open terminal - connected to +12
Relay 2 Wiper arm terminal - connected to car Yellow wire (input to computer)

If you draw this out, you'll see what's going on.

When you wire it this way:

• it is impossible to create a short circuit by pressing both remote buttons at the same time, or if one relay is stuck on (welded contacts on closure) pressing the other button does not create a short
• if you press both buttons at the same time, the effect will be same as pressing just the UNLOCK button (fail safe = open state)
• any random malfunction of the receiver unit causing it to activate any combination or sequence of relay pulls, is safe.
• Yellow wire can only possibly receive one kind of signal at a time, and rests in neutral (no signal).

__________________
Cheers!
Scott McPhee

1987 300D

Here's an example of a remote system to get for this job:

2 Channel RF Wireless Transmitter Remote Control 315MHz | eBay

And it's now down to $6.50 !! Can life get any better?


If the batteries in the remote fade, cheaper to get a WHOLE system with new remotes than buy replacement batteries.

Mine like this is still going strong.. how many years now?? Four!? Haven't had to replace the batteries yet, and I'm sure these are the cheap china no-name brand battery in there. Oh I see this particular one does not include battery.

I have one very close to this remote depicted (attachment). Nice remote with metal, and a sliding cover over two buttons with symbols that show lock and unlock. The remote is "thumb size" so you can see the receiver part is very small as well. I tucked the receiver up on the ledge of the right tail light assembly, because radio waves need to reach it, and easily penetrate the plastic shell and lens of the tail light assembly.


Problem with ebay links is they die fast, here's the text that came with the link I'm showing above, all Chinglish and everything, always amusing:


2 Channel RF Wireless Transmitter Remote Control 315MHz


Features:
This remote control switch can be used to control lights, electrically operated doors, windows, curtains, etc.

Technical parameters:
Working voltage: DC12V
Working frequency: 315 MHz
Maximum load: 10 A
Rx sensitivity:-100 dB
Encoding Type: Fixed code
Working way: a dynamic and interlock, since the lock (with IC a)
Output way: two groups of switch signals, 12 v voltage

Description:
1.with IC seats,can according change work way to L4/M4/T4, output way can be adjusted, can take voltage output with direct control motor and reversing, also can output two road independent switch signals, data bits can be adjusted.
2. Wireless remote control switch is a widely used wireless control device, the microprocessor intelligent control, it can be used in the garage door control, lighting control, remote control curtain and other fields, and has convenient installation is simple to use safe and reliable.

Note:Now this item not include battery, Post mail not allow ship include battery,buyer need have a 27A 12V battery.

Package Including:
1 x 2 Channel RF Wireless Transmitter Remote Control 315MHz
Keywords:Remote Control,RF Remote control,Transmitter Remote Control

Attached Thumbnails

 

__________________
Cheers!
Scott McPhee

1987 300D

i wouldn't go the cheap method. use an mb keyless entry system meant for our cars:

http://www.mbkeylessentry.com/1.html

i've been running with it for two years now and it works perfectly (of course the guy who owns the website installed it himself on my car)

__________________

You're welcome to spend eleven times the money for essentially the same function! Just pointing out the economical option for those so inclined.

Toodles!

__________________
Cheers!
Scott McPhee

1987 300D

scottmcphee
Can you post a pic of your setup? I am trying to do the same on my 93' 300D. A little confused on your explanation.

Thanks,
Tim

Very interesting indeed.
Might order one for the 300 SDL 1986.
Thanks SEV

__________________
Cheers
Big Dan MEng

Visit my Blog..
http://allformercedesbenz.blogspot.com/

www.benzguy.piczo.com



If at first you don't succeed,
Skydiving is not for you.

ARTIFICIAL INTELLIGENCE IS NO
MATCH FOR NATURAL STUPIDITY.

If anything can go wrong,fix it!
The hell with Murphy!!
I never think of the future.It comes soon enough.

On the system I installed I needed to tie into the wire that goes to the truck. Works great.

__________________
92 300D 2.5L OM602 OBK #59

I am about to install same unit in my car ('89 420SEL) and like to confirm following schematic.


Please let me know if i understood correctly or not. If some connection don't need please correct me so i don't cut wires unnecessarily.

__________________
1) '04 S500 Gold/Beige......120k Miles
2) '93 300E 2.8...Green/Tan MBTex..........202k Miles(and going)
3) '89 420SEL...Light Blue/gray Leather....155k Miles (Retired )

You understand this way better than me! If it works, will you post exactly what you did? I can kind of get the schematic but after I fiddled with it last night, my pump isn't working today. I spliced power from the module into the red and brown wire from the pump and it clicked on and off with the remote fine but I think the splicing chocks I used messed up the connection. After that, I was not sure what to cut and or splice, etc. Can you please make this easy for a non schematic reader? It looks like you know what you are doing. I have the exact same color wires in mine.

Thanks,

Steve

Whew! Good news. I rechecked fuses and replaced Fuse C3 which put everything back to working order. I also had rewired back to orginal status before I checked and now it is working fine again. However, I'm still hoping for an update on where to connect those other wires to after the initial power up connection for the China keyless Entry module unit.

Utruelove78....any luck or progress with your install based on your schematic? I know I can do it but don't want to screw anything up again.

Steve

OK...I give up. I tried every possible configuration of the diagram shown in this thread and all my unit would do was click on and off and flash the blue light. The vacuum pump still works. The door locks work fine even with the thing installed. I took it all out though and left my nasty butt connector mess to hold it all together. If anyone figures out what I'm doing wrong, please post....

Sorry this is not working out. Sounds like you have power to the module (red and black wires), so that is good. The six wires in the schematic are needed for the controls. One goes to 12V, one goes to ground, one goes to the air pump via the spliced wire (you can use any of the colors, I used green), one goes to the door via the spliced wire (again, green in my example), and two of the wires get tied together (that is the easiest connection).

I am a little perplexed that you have two yellow wires. Mine and the other ones I have been reading about had two green wires. I guess you could try splicing into the blue wire...it really shoudn't matter which one you do.

Keep me posted.

__________________
Treiberg's Collection: 1981 240D, 1985 300SD, 1992 300E, 1997 E300D, 2005 C230K

This all makes complete sense. You actually added details that are probably going to help folks out. On my schematic, I assume that folks will know how to connect +12V and ground, etc - but your notes makes this more clear, so thanks!

Besides the module wiring that I point out, the other two wires that need to be connected are the power (red) and ground (black) - this is what provides the power to the keyless module. Again, seemed obvious to me, but in hindsight is a neglectful omission.

Let me know how things work out.

__________________
Treiberg's Collection: 1981 240D, 1985 300SD, 1992 300E, 1997 E300D, 2005 C230K

Thanks for confirmation. I was thinking of tinkering with it today but decided to wait until someone confirms and gave it good wash instead . I also looked at Aussie max system which he says plug and play and liked the idea of using trunk light power and antenna ground that way i won't cut pump electrical wires, only the ones that operates the doors and trunk(yellow).
I will keep you guys posted with results and if successful will write up DIY with pics so it can help folks who are not very comfortable troubleshooting electrical things like me.

__________________
1) '04 S500 Gold/Beige......120k Miles
2) '93 300E 2.8...Green/Tan MBTex..........202k Miles(and going)
3) '89 420SEL...Light Blue/gray Leather....155k Miles (Retired )

Confirmed. For those who want to install this please use attached picture with my comments. I used existing diagram from treiberg and put comments if anybody get confused. I also installed at pump itself near spare tire. In addition to this I connected 2 brown wires(direction light in doc) to Parking light at pin 6 (gray/black) cable. I have to use both as I have w126 but in w124 you can wire only to one parking light and it will flash both. Working fine with factory alarm system as Lock/Unlock both from key/keyless system arms and disarms factory system. I confirmed this with leaving window open and while locked using key/keyless opened the door and alarm went off.
Thanks again to treiberg for providing diagram. It helped a lot.

__________________
1) '04 S500 Gold/Beige......120k Miles
2) '93 300E 2.8...Green/Tan MBTex..........202k Miles(and going)
3) '89 420SEL...Light Blue/gray Leather....155k Miles (Retired )