I am not able to adjust my seats in my '90 190E

. The controls all work fine except for the back, which will not lower.....but it will go up, which is causing me to lean forward in a very uncomfortable position. Anyone know what the problem could be or how to fix it? Is there not a manual switch or something to control the seats manually? If a car can be made in the earky 90's with almost more automatic functions and features of some of todays cars, then I'm sure the people at Stuttgart thought about a way to manuever around an electrical issue like this.