Yes, thank you for the info. I've done the hazard trick (in fact I use that instead of a turn signal to warn cars sometimes) with no success. I did find out one of my bulbs is out, but the other three are not. The hazard lights do light up, but do not flash.
Now my question would be, I have taken the relay off already to inspect it, and it looks like it is in good condition. Are the looks deceiving me? If so I'd just try your replacement and see if it works, or maybe borrow someone's that is functioning to see if that corrects the problem so I don't spend the money on it if it won't do me any good.
Also, unrelated. Could someone tell me where the other end of my speedometer cable is? I found (shortly after I bought the vehicle) that the cable was disconnected from the gauge, and I reconnected it. However, on the other end, I don't know if it is connected or not. Of course, if it is then I may have a broken cable, but there's no way to know if I don't check it. I've searched the forums and haven't found a description of how to find it for my model (1979 300SD, 116.120), so if you have one and know where to go, please let me know! Thanks in advance.