Hello everyone. I'm trying to trace down some electrical issues (yes, I know - a never ending problem) and I noticed I have two fan wires unplugged right next to these two white ceramic things. Can anyone tell me what they are and what purpose they serve? Also is there a modern solution that I could replace them with? Thanks!

 

I am reasonably sure that they are resistors. But, what function they have? I have not the slightest.

I have seen a similar device used adjacent to the ignition coil.

Teh devices are also known as ballast??

Car.

 

I don't have experience with S1 XJ6 but following is a guess
I suspect they are ballast resistors and part of the fan speed control.. The more resistance you put into the power going to the fan the slower it will go,
eg.
fan speed
high- no resistance
medium - one resistor
low-two resistors

 

Yes, they are power resistors that are switched in series with the fans to lower speed. On early S1 cars (up to 71 IIRC), there are two (not three) fan speeds, selected from the fascia-mounted rocker switch. "High" switch position supplies battery voltage directly to the motors, via a relay (again IIRC). With the switch set at low, the motors are supplied through the two resistors, which are wired in parallel. The low speed setting is also activated by a microswitch attached to the AC (Ranco switch) control. Switching on the AC compressor also switches the fan to low, even if the fascia switch is set to off.

On later S1s (not this one) there are indeed three speeds, just as Bill suggests. There are two separate resistors, but they are located in the plenum so that they receive cooling air. Low speed is the default when the fascia switch is off but the AC is switched on. Medium is is the fascia switch low position (which puts the two resistors in parallel), high is direct 12V to the motor via a relay. IMHO.

 

Thank you all for your help with this one. Much appreciated.