Electric Cooling Fans Running S..L..O...W

[Badger69]

Wrapping up my LS build and my damn cooling fans won't spool up.

I have them wired from the ECM and am using a dual LS1 set up from a 2000 Camaro. First fan runs when I hit 205, second is supposed to kick on at 215 per my program.

When I run the truck, the temp climbs to 205 and the first fan kicks on, but it spins super slow. Then at 215, the second fan starts up, but also spins VERY slow.

I used HP Tuners to force the fans on and I can hear my relays clicking. Getting 12 volts to the fans. Fans work when disconnected and wired directly to the battery. Verified temp gauge is correct by running HP Scanner. I assume it is a grounding issue, but my ground meters out.

Any ideas of what to check next?

Thanks all!