key fob zapper failed ....

[hannay]

'96 w124 E200

The zap function on my main fob has recently failed and I have been opening and closing the doors from the passenger side using a nifty hidden gadget that I believe is called a key that is actually housed discreetly in one of the fob's edge panels. Whatever will they come up with next!

This is all too much for me to be dealing with every time I want to open a door however, though nice Mr. Dealer wants most of £225 plus my firstborn for the privilege of being allowed once more to put my seat on to one of theirs.

I have done the camera-test and couldn't see any emission, also went to an automotive electrical place who very probably did the same thing in their back room and then said there's nothing there, mate ... 'll costcha!!

I have a spare fob, has been hanging on the hook for probably five years undisturbed at the least. Fitted new batteries expecting to promote it, but exactly the same, no emission ....

Can the Fob circuitry be replaced? .. though I guess coding is then involved and from what I understand that's not a DIY option and we are back to dealers and firstborns again.

Or do we have an electronic genius among us who knows that if you dip it in green tea and triple-strength Jack Daniels in the ratio of 2:1 for seventeen minutes at a temperature of precisely 81.7 degrees C the resulting electro-chemical reaction re-makes delinquent or tired contacts/circuitry and all is fine?

I know about the ebay/keys scams, thanks.

 

[bigasotonuk]

Hi,
I take it the fob you have is the single button type, with the key blade that flips out the side, via a button, if you look in the DIY section there is a "HOW TO" to repair these, and I believe to re-synch them after extended non-use, or battery change.
Don,t be tempted to try to replace with one sourced of off e-bay or the like as they are individual to the car, though it could be a source of spare parts to revamp your worn existing ones.

 

[teddycatkin]

The spare will probably need synchronising with the car after not being used so long -?
It may still be OK--as could the 1st-if you have had the battery out ?

 

[hannay]

Hi,
I take it the fob you have is the single button type, with the key blade that flips out the side, via a button, if you look in the DIY section there is a "HOW TO" to repair these, and I believe to re-synch them after extended non-use, or battery change.
Don,t be tempted to try to replace with one sourced of off e-bay or the like as they are individual to the car, though it could be a source of spare parts to revamp your worn existing ones.

Yes that's the one. Thanks for the pointer, I'm not sure the fault repaired there by soldering an internal component is the same fault with mine, however I will certainly check!

The spare will probably need synchronising with the car after not being used so long -?
It may still be OK--as could the 1st-if you have had the battery out ?

Yes the batteries have been out in both, main for a few days, spare for possibly 3-4 months now. both have been tried with new batteries in the last couple of days, and have been tested and found not to be sending out a signal so have been declared at fault by both local MB dealer and independent Auto-electrical bods.

 

[C180 Chris]

Yes that's the one. Thanks for the pointer, I'm not sure the fault repaired there by soldering an internal component is the same fault with mine, however I will certainly check!

Even if your switch is still attached to the PCB it may well have a leg or two off so give it a really close look over before deciding its not that fault.

Also to see if its working just put it in front of a digital camera and press the button, if its working you will see the infra red light through the camera.

Hope this helps,

 

[hannay]

Even if your switch is still attached to the PCB it may well have a leg or two off so give it a really close look over before deciding its not that fault.

Also to see if its working just put it in front of a digital camera and press the button, if its working you will see the infra red light through the camera.

Hope this helps,

Thanks Chris, I will bear that very much in mind when having a good look at it tomorrow now - no time this evening due to other commitments. Yes I already did the digicam trick - it was that that alerted me to the problem initially when I saw no signal ... lol it blew the dealer-guy away when he knew I already knew about that little trick so he couldn't perform his party-piece, lol

Best

 

[Dec]

I have a spare fob, has been hanging on the hook for probably five years undisturbed at the least. Fitted new batteries expecting to promote it, but exactly the same, no emission .....

It is quite unusual for the spare to be faulty too, given the possibility it had very little use over the years, any possibility that the batteries are installed incorrectly?

Dec

 

[kth286]

I agree - just check the batteries are installed correctly and then just re synchronise the key to the car as per the car handbook.

Do you have the handbook?

To synchronise mine, I just point the key with new batteries at the receiver in door handle and press button once then go and turn ignition key to position 2 within 30 seconds and the key is then synchronised.

You have a later model car and MAY be different as DAS was introduced on 1996 model year - so again check the book.

 

[hannay]

It is quite unusual for the spare to be faulty too, given the possibility it had very little use over the years, any possibility that the batteries are installed incorrectly?

Dec

I agree - just check the batteries are installed correctly and then just re synchronise the key to the car as per the car handbook.

These were my thoughts also on discovering that the spare was similarly not performing, along with wondering about the receptors/system, however both keys have been refitted with new batteries - and yes the right way around - and on my own check, dealer-check just in case, and local automotive electrical bod's test just in case in case, there is still no sign of signal being emitted ...

I am going to be checking the switch/PCB solder joints this evening, and hope for good news that way.

 

[bigasotonuk]

Hi,
You have made no mention of the red battery check LED which is visiable to the human eye, IR signal is what is seen through a digital lense.
Can you see this visiable LED?
Just for Info. have you got red & green LED's in the rear view mirror and by the boot lock? If so are they working or ever worked?

 

[hannay]

Hi,
You have made no mention of the red battery check LED which is visiable to the human eye, IR signal is what is seen through a digital lense.
Can you see this visiable LED?
Just for Info. have you got red & green LED's in the rear view mirror and by the boot lock? If so are they working or ever worked?

Thanks. Red LEDs not activating even when new batteries installed. Red and green LEDs in drivers door handle and by tailgate lock, not ever noticed in/by int mirror, working fine up to when zapper stopped.

Visitors stopped me checking the switch/PCB connection/solder tonight, hopefully tomorrow evening now.