What is this doohicky?

[pjsank]

This is attached to the heater fan wiring. What is it?
Looks a little banged up.

[Mercedesrover]

Fan motor resistor. Yes, it looks pretty shot.

[disco2hse]

yup. Resistance is futile.

[TeriAnn]

Fan motor resistor. Yes, it looks pretty shot.

Yes that would be on the low speed circuit of a 2 speed heater fan. There would be a switch position where the power fed directly to the fan and a low speed position where the wire wound resister would lower the voltage going to the fan motor and cause it to tun more slowly.

Sorry I do not know the resistance or wattage of the resistor.

[pjsank]

Since touching it broke the wrapped wire, I no longer had a lower speed on the fan. Just attached the remains of the coiled wire to both ends of the ceramic cylinder and it gave me a lower fan speed. I think I can just rewrap it with new wire and get it to work at a lower speed. Any idea where this thing is supposed to be attached? All the images of the heater don't even mention this part, not to mention where it is mounted.

[TeriAnn]

I think I can just rewrap it with new wire and get it to work at a lower speed. Any idea where this thing is supposed to be attached? All the images of the heater don't even mention this part, not to mention where it is mounted.

Resister wire is just that, a special high resistance wire. The end resistance is determined by the length of the high resistance wire.

This could be someone's add on to get 2 speeds. usually the resister is mounted on the two speed heater switch between poles on the switch.

[I Leak Oil]

NAPA sells a generic 2 speed heater switch with a built in resistor. Works for me.

[Howsomever]

As others have said this is special wire. Usually nichrome wire and length an gauge of wire plus properties effect overall resistance. This stuff can get hot and will hold together well over 1000 degrees. One common use besides high wattage resistors is for hot knives in cutting of foam and synthetic fabrics. Often this air resistance is mounted in the heater box specificially the air stream to help keep it from melting something else.

[lincoln lass]

This may help. http://uk.farnell.com/ohmite/l50j2r0...w-5/dp/1129678