Aftermarket keyless entry install
 

I took my 91 300E to have a keyless entry installed. I've done a lot of search in this forum regarding the way it is installed and found that hooking it up straight from the pump is the way to go. I asked the installer how he is going to hook it up and he said he will first install a new vaccum unit inside the driver's door which will push or pull the locking rod. He said the hook up straight from the vaccum pump is bad and causes the pump to burn up prematurely. Is this a true statement or this guy just don't know how to hook it up this way?
Can anybody out there with good knowledge in alarms or electrical/electronics, please shed some light to this. I don't feel comfortable with what he was saying so I did not have anything done to the car until I get some opinion from this forum. Also i need to know of a good alarm shop in the San Diego area that anyone out there would recommend. Thank you very much.

argghhhhh! amateur shop. if our m-b sytems were purely mechanical, then i would use a door lock solenoid in the door itself (volvo, vag are some). on our m-b, the wire for the electrical impulses (reversing polarity) can be located either:

1 wire by the kick panel
1 wire by the vaccuum motor itself (rear seat).

my advice? take it to a shop that has good knowledge with m-b's!



i worked 6 years as an electrical tech for auto shops. at 1 shop for 2 years, we worked with the m-b dealer in san francisco. m-b are really easy to work on if you know what your doing.

NO NO NO!!!! If he installs something that pushes the locking rod up, the alarm will still be armed - since no electrical pulses are travelling through the wires in the door locks. It'll go off when you press the button on your remote and this bonehead will probably take the easy way out and unplug the alarm module.

You need to run a wire to the vacuum pump, that way the alarm module disarm/arm upon unlocking/locking because it will "think" that the door was unlocked via the key.

i don't remember who posted it but there was a major write up including pics of how to install this

if i remember correctly the rear seats had to removed and some wires modded here and there

i think the parts were from crutchfield and cost like $75 for the parts


vacuum system diagram

steps on how (no pics)

step by step (with pics)

I thank you all for the expert and quick replies. It surely cleared my doubts about this shop's knowledge on MB's and avoided them from inflicting any damage to my car. I totally agree that this hit or miss "bonehead" like speedy said will disable the factory alarm and possibly create more problems. Now its time for me to shop around in the SD area for a legit MB alarm installer or would have to do it myself(which I tried to avoid because of my busy sked). Any suggestions is more than welcome.

You are in the San Diego area?

Geez, why don't you go to La Jolla Audio?

http://www.lajollaaudio.com/

These are the guys that reply to many of the posts in this sub-forum, under the name SCLJA.

Do a search on their posts and check out their website.

Remote keyless entry
 

Would the principles of installing a keyless entry system be applicable to all Benz's with the central vacuum locking system, or would each model and year have specific and critical differences? I am very interested in installing a keyless system in my '85 380SL (just to keep the keys away from the paint, Larry). Thanks

I'm pretty sure that your SL (1985 model) uses the same vacuum pump as the early W124's. That being said, the install procedure should be identical :)