E38 swap vehicle dual fan issues

[edcmat-l1]

Customer brought me a swap vehicle running an E38, bone stock engine, trans, to get the fans working. Vehicle was built by another shop came in running, just the fans didn't work.

Supposedly the wiring harness is PSI and their dual fan setup (no I have not contacted them). I got the fans to come on normally but once the second fan turns on they won't turn off. I can't turn them off with the scanner. Here's a little oddity to that. If I catch it with #1 fan on, before #2 comes on, I can turn #1 off with my scanner.

Once the temp is low enough that they should be off, if you turn the key off then back on, they're off.

You can watch the desired % go to zero and they never turn off. At a couple points in the log I tried to turn them off with the scanner controls.

[blindsquirrel]

Disable the Ignition Off timer crap. Also zero out the Desired vs AC, since I doubt PSI is integrating all the sensors and stuff in a standalone harness. Or maybe they do; if they didn't, then zero that.

Your (their?) Desired vs ECT is odd - it's set up as if there were only one speed, while the rest of it is set up for two speeds. I'd try it with just stock settings.

[edcmat-l1]

Disable the Ignition Off timer crap. Also zero out the Desired vs AC, since I doubt PSI is integrating all the sensors and stuff in a standalone harness. Or maybe they do; if they didn't, then zero that.

I'll give that a try. Don't know that it'll do anything for the issue but it's worth a shot.

Your (their?) Desired vs ECT is odd - it's set up as if there were only one speed, while the rest of it is set up for two speeds. I'd try it with just stock settings.

I want them on at 200 degrees full speed. They're not PWM. I don't think setting them up as "stock" is going to make any difference. I just want them on full speed at 200ish, and off by 192ish.

Side note, related to another thread discussing direction of coolant flow, this is definitely into the radiator at the top and out of the radiator into the waterpump on the bottom hose.

[gtstorey]

Someone else recently was posting this same thing but I don't remember if it was ever resolved.

[blindsquirrel]

I think it needs a second stage in the Desired vs ECT table, the ability to have a 2>1 step before it can go to 0. I don't think it will do a 2>0 step. Needs something in Desired vs ECT between 90 and 0. Just copy stock settings from a 2009-2010 truck.

[gtstorey]

I think it was this one that I'm remembering but not really enough info to really tie it down.
https://forum.hptuners.com/showthrea...&highlight=fan

[edcmat-l1]

I think it needs a second stage in the Desired vs ECT table, the ability to have a 2>1 step before it can go to 0. I don't think it will do a 2>0 step. Needs something in Desired vs ECT between 90 and 0. Just copy stock settings from a 2009-2010 truck.

I'll give it a try.

[Alvin]

Try this Ed, I'm not confident it will fix your issue but this comes from a proven file on our side.

2008 Suburban_fans - Al.hpt

[edcmat-l1]

Thanks Alvin. I was hoping you'd respond. I'll give it a try in a couple days. I sent them away with the truck and told them I'd be in touch.