Hi. My MB 190e 2.3 overheats in the summertime. Question is weather or not to start by replacing fan clutch or sensors.

I have located the 3 prong temp sensor that controls the engine fan and the auxiliary fan and have tried to short the two prong engine fan connection, but no luck, the fan does not come on.

When I jump the 2 prong connection to the single prong, the aux fan does come on. I am guessing it must be a bad fan clutch, but would like another opinion.

1985 Mercedes Benz 190e 4 cyl Two Wheel Drive Automatic 96500 miles

Thanks!