What is this??

[Fixitdan]

What is this ceramic encased device mounted vertically with one wire coming from each end. It is located just to the inside of the right headlight behind the grill. The reason I want to know what this is, is because it is rusted, cracked and loose to the touch.... Do you know what it might be? I would attach an image, however I can't figure out how to in this message board. '89 560SL

[rzrob]

It sounds like a resistor of some sort. Does it go to the ignition coil? It may also be something someone put in to supress noise from the radio. What year car? Is the item looking like a factory part?

RZ Rob

[Walrus]

That sounds like the aux fan resistor... For a 1988 560SL, this is the case... The resistor is in play when the A/C is on (I think), but not in play if the engine temp (water temp) gets above 105C. iirc, the aux fan runs at a slower speed when the ac compressor is turned on...

[Strife]

This is what I think it is also. Assuming that these are the same as normal electronics power resistors, they are possibly wirewound or filled with resistive material and then encased in ceramic. They can, and do, get really hot in operation and that's why they are made in ceramic. I'll bet getting hot and then exposed to instantly cooling water from rain eventually cracks them. If the cracks go deep, it is unlikely that the resistor is still in tolerance, and may possibly be open.