Zionsville SPAL e-fan only coming on at its higher speed

[peter540]

'03 540 with the complete Zionsville setup. Recently the 2-speed e-fan is only coming on at its high speed. I've verified its wiring/connections are all working correctly.

Might it be possible that there might be air in the system and that I need to burp it? I'm going to try that tomorrow, but I'm eager to get all of your thoughts.

Thanks, as always, for your help.

--Peter

[edjack]

Only way there's air in the system is that you have a leak. What is the operating temp? What is the coolant level?

[peter540]

Operating temp is where it should be for the 88° thermo -- mid to upper 90s -- and the coolant level is correct. Perhaps the reason the SPAL's low speed isn't coming in is that the Aux fan is kicking in when the SPAL normally would (Aux is doing this because I had DUDMD remap the coolant temp tables to eliminate the P0128 code I was getting with the 88° thermo).

--P

[peter540]

In speaking with another person with this same setup, we think the dual temp aux fan switch used exclusively in the Zionsville setup (to control the two-speed SPAL fan, mounted high up in the radiator) could be bad. I'll try changing it next week -- it's easy to do.