Hi all,

I have a 2005 R53, I have been working on it the last few months doing maintenance and repairs.
I’ve replaced the fan resistor on the shroud. I tested it with a power probe on the oval connector on the left side of the engine bay.
Both fan speeds work fine when power is applied to each pin on the connector, low and high speed so the resistor seems to be fine.

I let the car warm up and the fan came on at 105.7 degrees Celsius.
I had a diag scanner connected which shows fan activation, stage 1, 2, and 3.

All 3 stages were showing active when the fan kicked in.

Is this correct? I would have thought a scanner would show stage a single stage active when the fan kicked in?

Thanks.

 

I can't speak to what the scanner shows - but there's only two stages, low and high.
At 105° and the A/C off, the fan should come on low speed. You'll know it's low speed because it's very quiet. If you can very easily hear the fan while sitting in the car then it's on high speed.
You could also try measuring the voltage at the connector when you see the scanner showing activation of the fan.

 

Thanks for the reply.

My car doesn’t have AC, if that makes any difference.
I have a feeling it’s the high speed activating at 105c, I could definitely hear and see it running fast.

Need to do some digging as I know both speeds are working when I power probe the fan connector.

 

There are two relays in the fuse box under the hood that activate the fan.
When relay 1152 clicks on it activates low speed. When relay 1135 clicks on it activates high speed.