SLK Turn Signal Problem

[buellwinkle]

We have a '98 SLK230 and the turn signal blinker stops working after a while and then goes back to working after the car cools down. What happens is that when you use the turn signal after driving and have been using them for a while, specially on a warm day, it stops blinking. The light comes on the dash display and outside, front and back, no bulbs are out. Most cars have an easy to replace relay for this under the dash but not this car. When it works, there's a ticking you can hear/feel in the back of the fuse box in the engine compartment. Allegedly, there's a module that needs replacing. Does anyone know if this is a DIY project and what part I need to replace?