LQ9 Pulsed Cooling Fan output?

[HzEmall]

I have a LQ9 swapped in to my 79 C-10 with the Painless harness. It uses the OEM ECM and it sends out a cooling fan signal when it reaches temp and kicks on a 30 amp relay in the Painless Gen III fuse/relay box.

BUT, when it get to temp and kicks in the relay opens and closes none stop, sound like the turn signals are on.

Has anyone run into this? I can't see anything in the HP Tuner software that would make a difference with it.....

Thanks

[garys 68]

I would confirm the ecu is putting out a pulsed ground and it's not caused by a voltage drop to the relay. Some aftermarket fan controler put out a PWM signal to control fan speed, but I dont think the LQ9 ecu (411?) is capable of that.

[HzEmall]

i dont remember which one but its either the 89017733, 12576106 or the 12583560. Those are the ones Painless requires you to use with their harness. It's all based off of the 2002 4.8 parts I am told (ecm, tac, pedal etc)

[12sec ss]

There is a setting you can change with HPTuners, from 'PWM' to 'Discrete'