what part is this?? r129 500sl

[rellik]

ive been having some parasitic power drain after i turn off the car recently and i noticed a humming noise

i tracked it down to under the plastic cover for the CAN box in the upper right (drivers perspective) under the hood

its located right in front of the CAN box

the car is a 1993 500sl

here is a pic of the part:

that is the heater wate valve, also known as a mono valve, if there were two it would be a duo valve. it controls the heate water circulation

[rellik]

thanks, the alldatadiy images say thats the part!

could this be causing a power drain?

should it be running after engine shutdown?

thanks for the help
hersh singh

how long does it take for the battery to drain? do you have an amp meter?

[rellik]

ill set one up to see what the current draw is when off

is it normal for it to hum or vibrate afte the ignition is off?

thanks
hersh singh

Originally Posted by rellik

ill set one up to see what the current draw is when off

is it normal for it to hum or vibrate afte the ignition is off?

thanks
hersh singh

i would say yes, but it should be off i would say within 20-25 minutes. once the meter is connected try pulling the fuses until the draw is gone to isolate the circuit

[LeaUK]

Isn't it only active after ignition is off when you have pressed the button on the center consol?

Originally Posted by LeaUK

Isn't it only active after ignition is off when you have pressed the button on the center consol?

the EC Button?

[waybomb]

EC stands for no compressor in German.
I believe REST is what keeps the heat coming after shutdown.

[tecqboy]

The REST button ( residual engine heat ) activates the auxillary electric water pump and heater blower motor, but it should only run if the ignition switch is in the accessary position acording to my owner's manual. You know, I've never actually tried it.

[rellik]

hmm, i did install a refurbished climate control unit right before it started to cut out

[Carlos Serrano]

Interesting, When my Residual engine heat is turn on it keeps my interior warm after I shut down and lock the car. It blows low speed hot air as long as the engine is warm or it detects battery drain, then it turns off automatically.

[tecqboy]

I want to retract my previous post regarding the REST button. It does indeed work with the ignition off and the key removed. I went out and tried it. So, it is very possible that if there is a problem with the circuit, it could drain the battery. My manual is confusing on the activation. Sorry.