BU308

My '00 S500 has finally came up with something that I can't fix. Everything in the car had been running perfectly for at least the past 6 months. Started the car as normal after not driving it for 5 days, everything was fine. After 30 secs or so, I turned on the headlights, then the "display defective" massage came up (not again! I only changed the right front SAM last year!)

Here is a list of problems shown on dash:

-Temperature display on the dashboard gone
- abs light on
- handbrake light on ( I released handbrake already)
- BAS, ESP, airmatic malfunction warnings

Here comes the exciting stuff:

- I put the headlight switch to off position, headlights still on
- I pushed the start button to turn the car off( I was using keyless go), only my radio and the lights on the center console went off. The rest of the car was still on, I can still drive the car. Push the start button again, the radio and center console lights came back on.
- I put my key into the ignition, I didn't feel the suction and I couldn't turn the key.
- the air-con has no cold air.

I ended up pulling the fuel pump fuse to stop the engine running. Then disconnect the battery so the headlights and the rest of the electronics could go off. I haven't got time to try and reconnect the battery. I suspect this is again a SAM problem, but which one? Anybody got any clue? Thank you in advance.

vmystikilv

Weak battery or wet sam

BU308

Thanks for the reply, my car is parked inside an underground garage and I don't even drive it when it rains. I always check the drain holes for blockage. So I can safely assume I don't have wet SAM.

As far as battery is concern, my battery did died overnight and a new one was put in 2 months ago. What I don't understand is, how can a weak battery affect all these electronic system when the ignition is on? I thought the alternator would be doing all the work for electricity needed? Thanks

ibeforreal

You would be surprised at all the problems the batteries in these cars can cause.

vmystikilv

If you didn't put the right size battery or used battery then it could be the issue. The battery helps maintain peak voltage. When you are pressing the gas you get higher voltage and higher amperage . When your not, or say your electric fan decides to go insane speed it borrowes amperage from the battery instead of the alternator. It's actually a better wAy of dealing with things because you don't kill the alternator so easily by loading it up and down and the battery is a replacement part anyways. When no battery voltage or not enough amperage is avail, electronics start going crazy cause they can't fnd power to function properly . Kinda like telling a completely exhausted person that's delerious to go do something. Even if it's to sleep they will be to out of it to understand the environment around them

BU308

Understood, will look into the battery again. Thanks!!

tusabes

For a temporary workaround get a battery brain t3

http://www.amazon.com/gp/aw/d/B000P4H9W8/ref=mp_s_a_1_1?qid=1411445514&sr=8-1&pi=AC_SX110_SY165_QL70

Basically it has a remote you can use to automatically disconnect and reconnect the battery

BU308

Reconnected the battery tonight and everything was fine, did a nice long drive, so far so good Will keep an eye in the battery. Thanks again guys!