S124 alarm system

[jonsheaf]

Picked up the car today (a 95 E300d multivalve) really pleased with it on the way home, but a few hours later and I've been greeted with a handful of little old used car gremlins I think....

Inside the car (atop the dash speaker covers) are 2 alarm sensors. they are very period looking and have a red blinking led on them.
ON the outside of the bootlid, next to the handle is a little black square, when you press the MB central locking key (which doesn't work remotely to open the doors) the hazards flash and the black square alternates between a flashing red led or a flashing green led depending on how many times you press the button on the key.
Also (and this doesn't look particularly MB) is a little push button switch on the dash, presumably linked to part of the alarm as I cannot think what else it would be for.?!

Can anyone shed light on whether the system sounds like an original one? I assume as the original key transmits to it it should be?
Also any directions on things to check to make the system behave itself would be appreciated!

I will post the other gremlins in their relevant sections....

 

[boomtings]

hi ,

congratulations on your new car.
The push button and the sensors seem aftermarket.

the key and panels are from the mercedes system.
The ir key should make the doors open when the panel lights green and red when locking the doors. The boot panel should also lock/unlock the doors.

does the central locking operate via the key on the passenger and boot lock?

The alarm unit is under the passenger footwell metal plate under the carpet.

To test it sit in the car and lock it using the key on the passenger door. see if your movement triggers the sensors, also try and start the car the mercedes immo and horn should activate.

 

[jonsheaf]

Thanks Boomtings, I will test it out and see today.
The IR key doesn't operate the lock buttons at all but does arm disarm (green led/red led with hazard flash).
I had a bit of a mare last night, I think I got overly confused but it took a while to get the tailgate to open and the door locks kept trying to lock themselves, my poor old dog could see the park but couldn't get out!!
Finally I think the problem there was the trim around the (inside) tailgate was possibly fouling the locking knob, hence possibly causing the huge lock unlock pandamonium!!

I don't know if it means anything but driving the car home I did notice the left IR motion sensor led was blinking (should it be if disarmed?) and the right IR sensor, well that seems to have a missing led completely!

 

[Charles Morgan]

If your alarm / immobiliser is playing up (they are very old) just strip it out. Most are aftermarket, if you really need one, buy a cheapie off ebay.

Given your comments about wandering suspension I'd focus on that and getting a mechanical work programme as well as full bodywork checks. You can sink thousands into these now - just be very disciplined and concentrate on essentials.

 

[boomtings]

Agree 100% with Charles. Stick to a priorty list and in the begining live with minor niggles.

The bootlock problem you had is most likely due to you not being aware of the differences in turning the key both clockwise and anti clockwise. Does your car still have the owners manual.

You can also make a blink code tester , im sure there is a pin for the alarm.search for mercedes led tester and codes. I have a link somewhere ill put it up later.

 

[jonsheaf]

Today I have had NO issues with the dog getting locked in etc! And I have not messed about with any remote button or touched the boot lock, just unlocked as usual from the pass. door. All has gone well!
It seems you were right and I expect I got in a complete muddle with the locking system!
I have the owners manual yes, will have a scour through it, thanks.

 

[boomtings]

DTC list

Blink tester

Heres the links i said id post

 

[jonsheaf]

Thanks Boomtings!
I know it's old but the alarm is "only"?! missing the siren and the ability to open and close the doors, the other elements seem to work fine.
The boot is now fine ( now I've read how to use the lock properly)

I still have no idea what the aftermarket push button on the dash is for though, maybe it disables the motion sensors...

oh tried starting the car with alarm on and it started but I had hazards flashing!

 

[jonsheaf]

Just coming back to this thread, recently the locking had been getting a bit bossy and often would either lock us in (and the pump would still be trying every now and then), or would play "see how fast you can pull the door handle as I lock it" (hours of fun!??not!)

Well, as soon as the replacement pump arrived in the post, the remote locking decided a new game!! It worked perfectly !! grrrr!!!
I have since checked the fuses after reading about the gremlins they can cause, and found the comfort control unit 16A fuse to be really crusty.
Swapped it and fingers crossed it's behaving itself!!!

It has, as a parting gesture, managed to tell the wipers to intermittently say hello though.
I think I'm going to just replace all the fuses first of all!