On my 95 E320 I have noticed something very strange. The auxillary cooling fans work sometimes, not others. Twice, when sitting in traffic, I have had to turn the heater on full blast to pull the temp. needle from the pegged position.

The strange part is that when I pull over and lift the hood, I can just barely touch the cone of each fan and they will start spinning. I have found no rhyme or reason for when this happens.

The fans spin freely with no binding. I can feel a very slight magnetic resistence when slowly turning the fans by hand.

Since this started I have replaced the engine wiring harness (for other reasons), coolant temp. sensor (4 prong, black base on the thermostat housing), and fan resistor. I checked the fuses on the fan relays and they are OK. I even took the covers off the relays and the contacts appeared ok and moved freely. Any other suggestions?

Thanks in advance.