James3

Hi everyone I am having troubles getting my dad's 2001 SL up and running correctly after a prolonged time with a flat battery.
Stereo, electric seats and wing mirrors are not working. However the seats did work once but not do not work again. I have checked all the fuses under the bonnet (hood) and all seem fine. The car was fine when parked up a while ago. Any help would be appreciated. Thank you.
James

SRHsl600

So, the engine runs?
Did you use the radio code to reset the stereo system ( applies to older Benz, not sure about all R 129's )
Was the dead battery replaced or in vehicle charged?

James3

Hi thank you for answering. Yes the engine runs fine and the battery is new. The radio doesn't turn on at all. The electric seats worked once briefly since the battery was replaced.
I was wondering if there is some way of a reset of the electrical system?

bobterry99

This could be a faulty "Comfort Features" relay module. It's in the rear of the main fuse box. Might not be very accessible. If you have a multimeter for testing and wish to proceed, then reply back.

James3

Hello, Yes I can get a Mulitmeter from work no problem. Thank you for any input bobterry99.

bobterry99

If you remove the fuse box cover and expose the relays behind the row of fuses you will probably see a white relay -- the Comfort Features (CF) relay.

I would see if the CF relay is energizing. Have one person touch the relay while another turns the ignition key from position 0 to position 1 and back to feel for its contacts closing. Repeat the test by opening and closing a door with the key removed.

If you reply back with the result of that test I can suggest further troubleshooting steps.

James3

Hi mate, I have tried what you said and:
White relay (on left hand side of car when standing in front of vehicle) as in pic I can definitely feel actuating when doors opened and closed with ignition key out of car. Windows pull down and up when opening and closing.
With the key switching from position 0 too 1. I can't say for 100% as they all actuat at the same time. But I think so.
Thanks again for your time.
James.

bobterry99

With the relay energized check for voltage on fuse #21. On a U.S. car that supplies power to the mirror and seat controllers, and probably does so on your car as well.

James3

I checked fuse #21 with multimeter set at DCA 20m. I noticed a reading of between 0.14 / 0.22 for the mirrors.
Cheers
James

James3

Also notice that the electric seat work with the doors open but do not work with the doors closed.......

bobterry99

Either a power source to the CF relay is interrupted by a wiring problem, or the CF relay has a blown diode that you can easily repair. To verify the problem is the relay remove it and using the diode-check function of a multimeter check between pin 4 (+) and pin 5 (-) of the relay. If the diode is bad the voltage will be infinite. As an alternative to that check you could remove the relay and measure the voltage between sockets #4 and #5 of its electrical connector. With key on you should have 12 volts, and this would imply that the CF relay is faulty.

James3

Hey everyone so a quick update. First off the car is fixed. As my Dad just got a new Merc, he took his SL over when he collected his new car. They plugged it into the diagnostic computer and it returned quote "hundreds of faults". Not sure how true that is? Once cleared the only problem the car had was a £1.98 valve of some description. Once replaced everything is running perfect.
Thanks everyone for your time and especaly Bobterry99.