R129 IR Remote Central Locking 1990

[Biglee]

Anyone have any tips on where to start investigating non functioning remote CL. It use to work fine and from quite a distance. Was left a few months and when went to use no remote. So I changed the batteries in the fob. Also I changed the batteries in the second spare fob.

Batteries in both fobs now OK . Tell tale light comes on in fob if you hold down for a few seconds. Fobs are emitting IR as can be seen when pointing at phone and taking a video.

Central locking works fine and all red and green lights in door and boot work fine, when using the key. Lights flash when using the key manually.

When you use key and hold (for example when keeping key turned when locking to allow windows to close red lights flash. If you press fob whilst it is doing that the flashing changes slightly as though the car recognises that the fob has been pressed.

I have tried every re sync procedure I can find - EG 1 point and unlock ( as per manual) and also all of these : Synchronising one-button infra-red flip keys to the car

But still nothing. When I press fob nothing registers.

I have disconnected battery and left. Left key in ignition for hours. Also removed connector from control unit in boot and reseated (just to make sure). I believe the controller units are coded to the car, so cant just try a replacement from a 2nd hand car.

The fuse in the boot for cent locking (shares boot light) is OK and all other fuses have been checked.

Can you still get any of the replacement systems that converted to Radio remote and any experience of those. Do they still flash red/greenlights ?

I would really like to get the remote CL working on orig IR if possible. This is early system with nothing in the rear view mirror.

Appreciate any input to my problem. Thanks Lee

 

[Biglee]

Ps. Just redid the blink code reader in port 12 and no faults returned. 1 blink only. So car thinks CL is good.... At a loss now without sending it somewhere.

Thanks for reading.

 

[RichardF]

Not come across this so I'll put my thinking cap on. Have you tried it at each door and the boot?

 

[Biglee]

Yes Richard. Tried all doors and boot. Nothing responds. Is there a pin out of the controller or a way of testing the IR receivers? Is there anything else in the system, like the roof Ecu. I’m afraid electronics are not my strong suit., so any experience of testing the system appreciated.

 

[RichardF]

On the N54 module pin 4 trunk input infrared sensor input.
'using IR transmitter, lock at trunk keep button depressed monitor voltage, release button, voltage will raise approx. 0.4 VDC'

I'm thinking it's either a coding problem or a problem with Module N54 (RCL control module)

It might be worth asking here, this guy's helpful and pretty clued up.

Synchronising the single button IR Mercedes Key

 

[grober]

96 W/S 124 E200 remote central locking

 

[Biglee]

Well had a play today. Tried all resync procedures with both key fobs. No Luck. Found pinout diagram for the N54 remote module in the boot. Checked and 12v in to pin no 9 from fuse box in boot so that's good. Then checked voltage drop on pin no 18 when using the remote and it is Detected.. Note pin 18 it says left front door but this actually the drivers door. Also detected voltage drop on pin number 4 when using remote pointing at the boot. So I assuming the remote is ok and the receivers are ok. I guess next step is change the n54 module, but aren't these coded to the fobs does any one know in a very early 1990 SL500? So if you change one it needs to come with the fobs and swap the key ??? Anyone changed one of those modules? Part number is 129820062. It also has 5WK4 501 and 71.001.100 written on the module. For anyone else attached is the pinout diagram and the diagnostics checks.

Still trying to get it working. May leave it with just the key as the CL works fine.

Cheers Lee

 

[Zonergem]

Did you ever get anywhere with this? Having similar issues with added non-start problem.

 

[Biglee]

No never got anywhere with it. Still works with just the key. Its not a biggie as dont use it that much.