I have an 04 silverado with oem fans and oem harness using the pins on the pcm. The past week or 2 everything has been fine, but I noticed yesterday my truck got a bit toasty, and the fans aren't coming on for some reason.
The harness definitely has power, and I can activate the fans by pinning the relay with a test light. So the fans work, it just seems as the relays aren't being activated? I swapped all the relays also, still the same problem