1998 Other Mercedes Benz Models Clicking noise coming from e

I recently bought a 1998 Mercedes E430 with a little over 102,000 miles on it. I had a full pre-purchase inspection done of the vehicle and it came out with only maintenance work to be done.

Recently, I have noticed a clicking noice that is present about 75% of the time when the engine is running. It comes and goes. I opened the hood when the car was running and the clicking sounded like it was coming from the device that is directly behind the Windshield Washer System. I have a manual that came with the car, but it doesn't tell me what this part is. I have tried to find a manual on-line that will help, but to no avail.

Any thoughts on what may be occurring would be greatly appreciated.

Thanks.