The EC Button on the Air Conditionig Control Pannel on 300E w124 1988.

I now know what this buton does it serves no other purpose but to switch off either of the other two aircon buttons, this can be done anyway by half depressing the other buttons so no lights show on any of the 3x buttons. Now I have a useful propose for this econo button, to turn it into a proper econo switch. What can be done is going to save fuel costs and some brake pad wear and give you more power.

This is how it's done, get a switch that's operated by vaccum and it will operate via the econo switch, and brake the contact of the aircon switches when the vaccum is low (when your accelerator pedel is partialy depressed or pressed to the floor) this way your aircon switches off when you need power from the motor for going uphill or overtaking, but comes back on again when the vaccum is half way on your vaccum gauge or fully to the left. this way you will save petrol and have more power for going uphill or overtaking.
This also will save some brake pad wear as when you deaccelerate the drag of the aircon compressor will give more engine braking and save some break pad wear.

It's a win win modification and every thing to do it it accesible in the vicinity of the switches all you need is a $20 adjustable vaccum switch a couple of bits of wire and some switching knowledge to turn the econo switch into something that is useful. Here are two web pages for the type of switch that you need.

http://www.autospeed.com/shop/category_706/browse.html

http://us1.webpublications.com.au/static/images//shop//hi/888800079hi.jpg


Cheers George