Here is a possible solution for:

No intermittant wipers AND/OR No turn signal AND/OR No hazard flash.

Had all these things quit on my wife's 1994 C280. They are all controlled by a "combination relay" referred to in the prints as "N10".

To access this combination relay, open the fuse box cover on the fuse group under the hood, near the windshield on the drivers side.

Next, use a phillips head screwdriver to remove the 6 black screws holding the top cover on. ( The screws are captive, they dont actually come out of the cover but you loosen them all the way)

When you remove this top cover, you will uncover a group of modules closer to the windshield. The biggest one is N10. Its black. Pull this out by hand, it should come out easily. It is keyed so it can only be inserted one way. My relay, the original, had printed on the side:

201 821 00 47

05 8983 01
12V/2(4)x21W
max.6x32cp

DOT SAE
J590e/945b
@ 719043

Now using some small jewellers flathead screwdrivers, carefully pry off the cover on the combination module. Dont stick screwdrivers way in there or you may damage the stuff inside.
With a little patience it comes right off, and if you crack the cover it doesnt matter; no one can see it anyway, right?

You will see a printed circuit board with 3 relays on it. Where the board meets the plastic base, there are a row of solder points where the board is connected to the pins and base. Do a careful examination of these connection points for cracked solders. If you find any, you can remelt them with a soldering iron. I could see two cracked solders on that bottom row of my relay.

Assembly is the reverse.

Perhaps, like me, you will find a cracked solder, fix it, and get your car back working for only a 1/2 hours time invested, no money, no parts.

At least, if you are going to buy another one anyway, take the old one apart first and give it a go. What have you got to lose?

Good luck.