New uses for the W124 cellphone armrest - PeachParts Mercedes-Benz Forum

Jeremy5848 · #1 09-30-2012, 12:25 PM

Late W124 models have the option of an armrest-mounted cellphone; the wiring is in place whether the cellphone was installed or not. With the help of GSXR (Thanks, Dave!) I found the cable under the seat and rerouted it to use with my garage door opener. Here’s how I did it. You’ll probably think of other uses so please suggest them.

The cable from the cellphone comes out of the armrest, passes through the driver’s seat and dives into the carpet, never to be seen again. It turns out that there’s a plug and socket in the cable hidden under the carpet. If you pull them up you can plug in your own device.

Please note that the connectors are RJ-45 (8 pins) network connectors. Standard 2-, 4-, or 6-pin telephone cables WILL NOT work. I used a female-to-female adapter and a network cable from my junk box. The cable was pulled under the carpet and up into the console.

The only switch with SPST momentary action that I could find in my collection was a rear window washer switch from a T-sedan (“station wagon”). Actually, it’s DPST but I ignored one set of contacts. The switch was installed in one of the positions in the “limo wood” console panel, available from Mercedes as an option for all 124s (124 683 38 37).

Only four wires are used so I removed the unneeded contacts from the socket. Two wires connect to the network cable for the garage door opener and two wires power the illumination of the switch.

A short stub of network cable was added to the opener in parallel with the existing switch. The opener can be removed from the car by unplugging the network cable from the armrest. This allows the opener to be used outside of the car and also makes changing the battery easier.

The opener now lives in the armrest where it’s out of the way yet easily accessible if needed. It has no problem from that location opening the garage door. I padded the opener with a spare pair of gloves so it won’t rattle.

Obviously you don’t have to use the same switch or the same switch location as I did. Wherever you put the switch, make sure it’s in a location where it can’t be accidentally pressed. You don’t want the cat opening the garage door in the middle of the night.

There have to be other uses – 8 wires is a lot, you could install an MP3 player, for example. Use your imagination!

Jeremy

EDIT: To remove a source of confusion, I changed the second sentence, which formerly read in part, " . . . I found the cable under the seat and rerouted it to use as a garage door opener." The sentence now reads "with my garage door opener."

gsxr · #2 10-02-2012, 12:23 PM

Excellent write-up and photos, Jeremy... very nice install! Love that limo console wood too...

ah-kay · #3 10-02-2012, 12:39 PM

Shouldn't the garage opener a wireless device already? You have an answer and try to fit a question to it?

gsxr · #4 10-02-2012, 12:43 PM

Quote:

Originally Posted by ah-kay

Shouldn't the garage opener a wireless device already? You have an answer and try to fit a question to it?

Jeremy's modification makes a factory switch open the garage door, instead of having to fumble around with the opener, or having it clipped to a sun visor, etc.

ah-kay · #5 10-02-2012, 12:53 PM

Quote:

Originally Posted by gsxr

Jeremy's modification makes a factory switch open the garage door, instead of having to fumble around with the opener, or having it clipped to a sun visor, etc.

It still does not make sense to me.

1) Too much work for what it is.
2) Not portable to the next car/house owner.
3) Entails work to swap out new garage opener and remote.

I am sure it is a good idea if you run out of honey dew list to do.

sixto · #6 10-02-2012, 12:59 PM

This brings the homelink feature of later MBs and many other makes to the 124.

That's why there are handicap placards you hang from the mirror and dedicated handicap license plates.

Sixto
87 300D

Jeremy5848 · #7 10-02-2012, 01:41 PM

Quote:

Originally Posted by ah-kay

It still does not make sense to me.

1) Too much work for what it is.
2) Not portable to the next car/house owner.
3) Entails work to swap out new garage opener and remote.

I am sure it is a good idea if you run out of honey dew list to do.

1) I'm an engineer -- it's what I do. "Too much work" for you is "fun" for me.

2) Easily portable, just unplug the cable and remove the remote. For a future owner, clip the cable.

3) New GDO, simply move the cable to the new remote.

You see problems, an engineer sees opportunities for fun.

Jeremy

compu_85 · #8 10-02-2012, 01:47 PM

Yes... it would be "not portable" if the wires were hard soldered to the opener the whole way. The RJ45 makes future changes easy

-J

ah-kay · #9 10-02-2012, 02:00 PM

Quote:

Originally Posted by Jeremy5848

1) I'm an engineer -- it's what I do. "Too much work" for you is "fun" for me.

2) Easily portable, just unplug the cable and remove the remote. For a future owner, clip the cable.

3) New GDO, simply move the cable to the new remote.

You see problems, an engineer sees opportunities for fun.

Jeremy

With no dis-respect. I am a engineer and engineering is fun for me too. I think it is a good idea and a good write up. I admire your thought process to 'improve' the car.

Keep it coming.

daw_two · #10 10-02-2012, 02:12 PM

I like it, Jeremy.

I hate putting the garage door opener on a Mercedes sun visor --- I've refused to do it in my present daily driver. It puts a crease into the sun visor and it's hard enough to find good sun visors. Good write up and great pics! I love pics with these kind of things.

Engineers Rock!!!

Zulfiqar · #11 10-02-2012, 02:20 PM

I dont have a garage door to open, so its out, BUT this is a brilliant idea.

Jeremy5848 · #12 10-02-2012, 02:35 PM

Quote:

Originally Posted by Zulfiqar

I dont have a garage door to open, so its out, BUT this is a brilliant idea.

8 wires! You gotta think of something! Parallel printer port!

J.

Jeremy5848 · #13 10-02-2012, 02:36 PM

Quote:

Originally Posted by ah-kay

With no dis-respect. I am a engineer and engineering is fun for me too. I think it is a good idea and a good write up. I admire your thought process to 'improve' the car.

Keep it coming.

Thank you. Next topic: daytime headlight switch.

J.

Jeremy5848 · #14 10-02-2012, 02:42 PM

Quote:

Originally Posted by gsxr

Excellent write-up and photos, Jeremy... very nice install! Love that limo console wood too...

I was concerned that all the switches in the limo wood console panel would look too busy. They don't, it all looks like "it belongs there." (I guess it does, now.)

Jeremy