Newbie question, I've searched a few threads on this topic, but many didn't lead anywhere, nor did their recommendations resolve. So I've converted my 2001 Suburban to using 2005+ HD fans using a Nelson Performance Fan Harness. Plugged the blue wire into Blue#42, Grounds, and Power etc. Then proceeded to enable 2-Fan in HPTuners and flash my PCM.
However, now my fans run constantly. As soon as engine is started. (Actually need to confirm if in ON vs RUN, etc.)
This Radiator (34in 2-Row Aluminum) is too efficient to have fans running constantly and allow the engine to come up to operating temp. We're talking ECT values not getting above ~150*F unless I manually disabled FAN 1 in VCM Scanner during a drive test...
Here are my settings, I need to confirm relay operation still (Should get that done this evening):
HPTSettings.PNG