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2001 SLK320
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139 Posts
Discussion Starter · #1 ·
2001 SLK 320
Bought remote key fob from ebay, took mine and the new one apart, swapped circuit board and key. Basically, my housing was worn smooth.
Stepped into garage, pressed lock and unlock, worked. Pressed alarm, worked. Got in this morning, turned the key, started and died. Tried again, started and died. Now it wont even try to start.
What happened? I tried to press the buttons 2X and turn to pos 2, but since it was already locking and unlocking, that did not seem to need to be done. However, did it anyway, several times, no joy.
Is it tow truck, new key time?:confused:
 

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2001 SLK320
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139 Posts
Discussion Starter · #2 ·
Okay - towing fee later, I know what I did wrong or missed.
First of all, luckily I had already arranged for the dealer to get me another key so they had one ready to code for me, so I was only out the towing fee and half a day of work.
IF you should be so inclined as I was to buy a new housing for your worn out remote, there are 3 things you have to move over.
The metal key, the circuit board AND (this is what I missed) the passive chip that identifies the remote to the car's computer. I thought it was on the circuit board. On the red lens end, there is a white plastic cover that holds down this tiny quadrangular shaped piece no more than 1/4 long and 1/16 thick. Once I dug the old remote out of the trash, found it, swapped it into the new (old) remote, wallah, now I have two remote key fobs.
 

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2002 SLK 32 AMG 1965 Mustang V-8 Convertible
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146 Posts
Nice info to have as our R170 SLKs and their key fobs age. Thanks for sharing the details, I would have thought the circuit board swap would be enough too.
 

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1998 Silver SLK Salsa/Black Interior
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24 Posts
Thanks for the information. I've been wondering about this for a while as my 1998 Key fob is on its last leg. How much did you pay for the Key Fob shell and did you replace it with an exact duplicate shell or an updated version?
 

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2001 SLK320
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139 Posts
Discussion Starter · #5 ·
I paid $25 but then got $10 back because it wasnt the one in the photo.
I bought one exactly like I had. It was advertised as a remote key fob, key already cut, just need to code to your car. Obviously, I already knew this was false. The key could NOT fit since, just like any other cut key, it has to be cut for your car's lock cylinders. The circuit board might be able to be recoded, but the passive chip cannot be coded and must be swapped over. So since you gotta crack it open to get the chip, just expect to change it all. You have to pull the circuit board to get to the chip, so you might as well swap the board, too.
 

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1999 SLK230 Sport 5-Speed Manual, Silver, Subtle Red on Black Interior
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116 Posts
Part 1 - Separating the OEM Remote Shell

I had also looked into replacing my remote shell and below are my insights. I had an OEM key FOB from a former 1999 SLK230 to test with, and did my best to gently separate the parts and preserve the original remote shell.

The OEM electronics may be damaged during the separation of the remote FOB halves.

While separating the halves of the OEM FOB, I found that my remote halves were glued together. The glue appears to be factory applied, there were no exterior signs of glue or excess glue build up inside the remote that would be expected if a previous owner used super glue and pushed the halves together. I imagine that all OEM remotes would be glued the same. The glue makes it extremely difficult to separate the halves. There is very little room to get leverage with a flat screwdriver, putty knife, or similar. The torque required to break the glue bonds while holding the small remote in your hand inevitably leads to driving the tool into your hand, fingers, wrist or forearm, which I ended up doing seconds before I was going to put on work gloves. Holding the remote on a flat surface and trying to pry apart was little better and still resulted in the tool slipping and or flinging the remote away. If you have a vise available to clamp the top half of the remote and pry off the bottom, you may have a better chance of the electronics surviving the separation vibrations and jolts (but I expect you would just fling the remote further as it slips out of the vise!).

The unlock switch (which had been working perfectly) on my OEM circuit board broke free from the jolts during shell separation - you may have white oxidation of electronic circuits on our aging circuit boards that weakens connections, similar to the common K40 relay corroded circuit issue. The jolting from prying apart the halves could result in some of these parts breaking free, which require precision soldering to reattach. There is also the risk of driving the prying tool into the circuit board at some point during separation due to the lack of control as the prying force finally breaks the glue bonds.

OEM shells - yours or a semi-used OEM you buy somewhere in order to scavenge the shell - will likely have cosmetic damage from the shell separation

Due to the torque described above, your glued OEM remote will have gouges and indentations from the prying tool. If you weren't concerned with looks, then save a ton of aggravation and don't switch shells! :)

If OEM remotes are presumed to be glued together, buying any used but better-than-yours condition remote just for the shell is a risky option since the shell is likely to be damaged during separation. However, cwickgo9 had success and didn't indicate trouble opening his presumably OEM remote shell. It sounds like he ended up getting a never-used or slightly-used OEM remote, which isn't a ready supply the rest of us can access. cwickgo9, please post the eBay store name (hyperlinks become invalid quickly as listings end but are then relisted by the store) - does it appear to be a one-time listing or does the store have more? Also, did your remote have the red lens on the end of the FOB, and did it have FCC ID: KR55 and other info printed on the back (which would indicate OEM versus aftermarket)? I've searched eBay and the web far and wide and I'll post my experience with aftermarket shells in the next posting.
 

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1999 SLK230 Sport 5-Speed Manual, Silver, Subtle Red on Black Interior
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116 Posts
Part 2 - Finding a Replacement Shell

Look on the back of your OEM SLK remote and get the FCC ID - my 1999 SLKs have remotes with FCC ID: KR55 This will help in your searches - there is a remote that has FCC ID NCZMB1K - I believe this corresponds to remotes that have the 3-button+panic button arrangement that otherwise appears identical to the SLK 2-button+panic FOB.

Closest available aftermarket shell doesn't have red LED lens

Throughout my web searches (mercedes key fob, SLK key fob is too narrow), the closest replacement shell I've found is through eBay seller vistaremotes for $37 after shipping, indicating KR55 in the listing title. Despite pre-purchase emails and a similar listing of his indicating the availability of a 2-button+panic version of the shell, he sent me the 3-button+panic version of the remote, and then on follow-up turns out he does not have the 2-button+panic version. The 3rd button has the open trunk symbol, and our boards do not have a button for it. If pressed, the trunk open button would not damage our OEM SLK circuit boards, since the button would not extend down enough to touch the board.

While the Red Lens at the top side of the remote may only be used for checking battery and switching unlock modes, the fact that it is missing on the eBay vistaremotes shell may be a concern for you. I also seem to have seen postings where an LED bulb is soldered to the OEM SLK remote circuit board and this aftermarket shell would not have room for the bulb. My OEM SLK remote had a bulb-less LED on the circuit board, so it fit the aftermarket shell.

Closeness of fit on Aftermarket shell may make button activation overly-difficult

I fitted my original OEM circuit board into the aftermarket shell and the panic button would not activate without heavy pinpoint fingernail pressure. I found if I pressed up on the circuit board through the battery access panel, the panic button was a bit easier to activate with fingerpoint precision, but not near the level of easy thumb-press activation of the OEM, so you may need to find a way to build up the thickness of the board (tape, glue,?) along appropriate edges to wedge the board higher in the shell in order to get better button activation. The lock button was activated easily similar to OEM, my unlock button switch was no longer attached to my board for testing (see posting Part 1). While my aftermarket remote shell had problems with the panic button (which may not be a big concern for you), it indicates that other remote shells from other batches may have a similar problem with the lock or unlock button not working well enough.

Other Differences

The aftermarket shell is the same thickness and dimensions as the OEM, but does not have the FCC ID and other printing on the back of the remote, indicating these shells are not coming from OEM suppliers. The switchblade release button on the aftermarket remote sticks up further than the OEM, and the soft-lock / hard-lock functionality was reversed. On the OEM, when the blade is in the open position, you can push it back into the FOB without pressing the button (what I call the soft-lock). The aftermarket FOB requires a press of the button to allow pushing it back into the FOB. Noticing that, I tested prying the blade out without pressing the release button on the aftermarket shell and it came out with the OEM soft-lock feel. For me that would have been a huge irritation if I continued to use the aftermarket FOB.

The remote shell has a wider cut out for the key blank because it is made to handle both the narrow style blade of the SLK and wide style Mercedes blades. Not much of a drawback, but reiterates that it has the fit of a universal part rather than SLK-remote-specific purpose.

Best of Luck!

These are some of the drawbacks and differences to consider when looking for a replacement shell. I'd love to find a good alternative shell, but after far too much effort to save some money, I'm giving up and paying the stealership $150 for a brand-new functioning remote (with new electronics that haven't been oxidizing and getting bumped around for a decade). But hope springs eternal, so if anyone finds a source of quality replacement remote shells that have the led lens and OEM-quality button activation, please post the details!!
 

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2001 SLK320
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139 Posts
Discussion Starter · #8 ·
Thanks for the extensive write up MB. I had no real issues prying mine apart. There was glue, but apparently was lightly used or old enough that with enough slow, gentle pressure and 3 different sizes of screwdrivers, I had no real issues avoiding any real cosmetic damage. If you start in the area behind where the key resides, that works best.
Also, take the battery lid off and batteries out first.
The new unit I have from the dealer has the red lens, but NO visible light emits from it, and there was no LED or any type of light emiting divice on either of the circuit boards from the units I took apart. I'm unclear as to the reasoning for this lens.
I would not hesitate to do this again.
 

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1999 SLK230 Sport 5-Speed Manual, Silver, Subtle Red on Black Interior
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116 Posts
Replacement Remote Key FOB Shell with Red Lens

I purchased a replacement Key FOB shell off eBay recently that is good quality, it appears like it uses the same molds as the OEM FOBs. It also has the red lens that is used for some rare remote feature programming and to check battery strength. Oh, it costs less than $9 delivered (to the US), and takes ~2 weeks to arrive. One improvement over OEM is the red panic button has raised letters rather than the white paint letters that rub off quickly.

Links to eBay listings get quickly outdated, so the seller is mxqtech and you should search his ebay store like this link
Flip Folding Remote Key Fob Case Shell for Mercedes-Benz SLK 230 320 32AMG 98-04

The circuit board inside your remote either has a bulb or a tiny led on the back of the circuit board that will flash when you hold certain buttons of the remote a certain amount of time. I've had OEM remotes from the same model year one with the bulb and ones with the led - go figure.

Feel / sensitivity /ease of pressing the buttons is same as OEM. The one installation hint I found with the 2 eBay remotes I purchased is that I used the push button from my original remote in the new shell. For some odd reason, the push button with the new shell doesn't lock into folded position with my OEM flip-out key. The new push button does lock closed with the blank key they provide in the new shell, but cutting the blank key at a specialty shop costs minimum $30 in my area.

One other note is that the white plastic insert that holds the transmitter in place is not included, so use that part from your worn out remote.

Here are pictures comparing OEM to this eBay supplier. Overall I am pleased with this aftermarket FOB, unlike other eBay FOBs I reviewed in the past.

Font Technology Auto part Electronic device Vehicle door
Bumper Material property Auto part Automotive exterior
Bumper Automotive exterior Material property Auto part
Electronic device Technology Font
 

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Australia, 99SLK230 R170, 2001SLK32
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1,387 Posts
fantastic work and research mbpaul!

Stop being such a miser with your interlect!....;>)what you have done is ...yes you spent a lot of time and pain trying and trying again.....researching etc....

But it's not only you that benefits!....

I spent a couple of hours with mine and tried to prise the RFID chip out but didnt persist for fear of breaking it.
After reading this, all the hard works been done !...by MBPAUL!...fantastic....
- I just went on ebay now and ordered one from mxqtech. $8 Australian landed!.....
sweet!....keep up the good work whenever you feel the urge.

I love the communal aspects of the internet....long may she reign!
 

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2013 E350,2008 E320 Bluetec (until 11/14), 2004 Volvo V70, 2001 SLK320, 1972 MGB
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182 Posts
Bought the $9 shell from Ebay, took guts including key from MB remote, fitted in new shell, works perfectly. Took abou 15-20 minutes (working carefully). Bought from US based vendor, took 3-4 days to arrive by mail.
 
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