|06-06-2010, 03:17 AM||#1 (permalink)|
BenzWorld Junior Member
Date registered: Feb 2010
Vehicle: Mercedes Benz SL500 1995 / Mercedes Benz 1981 380SL
Location: Southaven MS
Infrared keyless entry 95 sl500
It seems that my keyless entry is not working. I tried new batteries with no luck. What is the next logical step in this troubleshooting procedure? thanks for the help.
|06-06-2010, 04:32 AM||#2 (permalink)|
BenzWorld Senior Member
Date registered: Dec 2009
Vehicle: 1995 SL500
My 1995 did this once randomly as well. Using the regular key to cycle the lock on the drivers door reset it somehow. Not sure it is your problem, worth trying though.
Mine did this only once oddly and normally works fine.
|06-06-2010, 02:04 PM||#5 (permalink)|
that doesnt sound like it is the case here...
Test the remote itself to make sure it is still operational, hold the button for 3-5 seconds, make sure the tip flashes in red.
next, try to resync the key, lock, unlock the driver door with the key blade, put the key in the ingnition, turn to position 2, then off again, then cycle the key blade one more time in the door, while the green light of the door is still flashing green, aim the remote and push the lock switch. the flashing will pause if the car recieves a signal..
at this point, the key must be resynced, and you should be able to lock and unlock normally with the remote.
if the flashing stops (as mentioned above) but the car still does not recognize the key, you either have the wrong remote, or a bad module.
If you post to ask "is the car worth the repair?", get rid of your 129/140 and go buy a 2013 Corolla... Classic Benz is not an investment for you...
Mercedes-Benz, W140 S Class S320 (AKA 300SE)
Mercedes-Benz, R129 SL Class SL500 (AKA 500SL)
Mercedes-Benz, W163 ML Class ML430 (Designo Edition)
Triumph Daytona 955i - SSSA
W140 S Class 500SEL (sold) - W140 S Class S500 (sold) - W140 S Class 500SEL (sold) - W201 190E 2.3 (sold)
|06-06-2010, 07:20 PM||#6 (permalink)|
BenzWorld Junior Member
Date registered: Jan 2009
Vehicle: SL500 1990, USA specification. Chassis No. WDB FA66E5 LF 005675
Location: Dubai, U.A.E.
Keito, the electronic internals of key-fob do become damaged or defective over time. High chance that solder joints have become dry, or fatigue fractures developed around a component.
Question - is the keyfob creating an infra-red signal?
Even the visible light 'flash' seen after 2/3 seconds does not always mean an infra-red signal is going out.
Quick way to test this - use any digital camera (or camera-phone). Hold fob pointing toward your phone / camera. Press activation button, watch camera for 'flash' from module that naked eye cannot see. If no 'flash' (which is more like pulses, than a flash) then internals are defective and need re-soldering etc.
Try with any tv or stereo remote to see camera spot what naked eye cannot see.
There is a post of about two years back with photos, where a fob was opened and internals / battery posts re-soldered.
Good luck and regards,
|06-06-2010, 08:30 PM||#7 (permalink)|
the key fob internals consist of surface mount components with a slim to non chance of delaminating under regular to extreme conditions...
also, all components in the key fob are solid state, except for the switch itself.
as far as the infrared beam, it is visible if you look at it in a dark room, so no need for the camera.
furthermore, the PCB, by design, makes it very hard to fail in a fashion that allows the test red LED to be excited, (notice the name "test LED", infrared not to be emmited...
basically the key for circuity is so simple, that you may get all or none in 99.999% of the cases...
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