psycho,

This is what it says for your car at ********:

http://www.**********.com/search/product.aspx?sid=5mtnntqddgnaoqbdnzcjj055&makeid=800016@Mercedes&modelid=1194364@300TE&year=1988&cid=18@Electrical%20%26%20Vacuum&gid=3608@Multi-Purpose%20Relay/Combination%20Relay