Disabling '88 560SL Alarm - PeachParts Mercedes-Benz Forum

MC06A · #1 06-30-2007, 08:10 PM

The alarm on my 560SL started going off when my brother unlocked the car. I couldn't get it to stop so I disconnected the battery. I'm thinking about just disconnecting the alarm system all together.

I understand that in order to do this, I need to get behind my glovebox. I have already gotten back there, but I have no idea which ones to unplug.

I took a picture so it might be easier to explain to me.

Thanks.

And while I was back there, I found an open ended tube connected to nothing. Anybody know where it goes?

ScottinSoCal · #2 06-30-2007, 09:18 PM

Quote:

Originally Posted by MC06A

And while I was back there, I found an open ended tube connected to nothing. Anybody know where it goes?

The open ended tube is supposed to be connected to the sensor on your dash for the climate control (heat/AC). MB used a foam tube to connect the two and the foam has obviously disintegrated.

Get a piece of 3/4" tubing and connect the two back up and your climate control should start acting more responsive.

MC06A · #3 07-01-2007, 01:44 AM

Thanks Scott. Is the tube supposed to connect to another tube? I looked/felt around and there wasn't any there.

ScottinSoCal · #4 07-01-2007, 09:15 AM

Quote:

Originally Posted by MC06A

Thanks Scott. Is the tube supposed to connect to another tube? I looked/felt around and there wasn't any there.

Directly under the sensor on your dash there should be another tube - it comes down from that sensor.

The way the whole tube thing is supposed to work is the actual temperature sensor sits inside the little black grill on your dash. The tube going back to the firewall leads to the input side of the blower fan. The fan causes air to be drawn in through the grill in your dash and across the temperature sensor, then into the fan blower. It improves the accuracy of the temperature sensor and makes the climate control system more accurate. It isn't required for your system to work, but without air pulling across the sensor it'll just be reacting to the dash temperature, instead of the air temperature in the cabin of your car.

The actual sensor is just a tiny little thing that looks like a soldered wire end. You should be able to see it through the grill in your dash. I'd take pictures of all this to show you but my car is currently in a shop 40 miles away getting a rebuilt transmission.

Alkraut · #5 07-01-2007, 10:18 AM

Scott is correct, the tube is part of the hose that goes to the interior temp sensor. The sensor is a two-piece device. There is the upper plastic part with the "grill" on top of the dash, and the lower part with a nipple to accept the hose that provides the correct temperature. The two plastic parts snap together, one from top, other from bottom. The actual "thermistor" sensor has a wire going to it, and it comes from the side, not through the hose. There is a small connector on the thermistor. The original Mercedes "hose was made of foam rubber, probably to be insulating. Over time, they all dry out an powder away. I used a piece of clear flexible tubing from Home Depot. One side connects to the black hose you see, the other to the plastic nipple. It's hard to see it from the glove box. Try feeling up there for it.

As far as the alarm "black box". You should see it on top of the duct with two connectors. The number on mine was 126 820 0826 (this was based on notes I wrote last year when I was in there on my 560SL). Not sure what you do to disconnect the system. Good Luck.