Power going to fan relay when car off, causing fan to run while key is out and draining battery.

[Ginko]

I have to 2009 pontiac vibe and an electrical issue cropped up while I was trying to fix a starting issue. The radiator fan will turn on once the car is off, depleting the battery completely. I've narrowed down the problem to the power going to the fan control relay, but I'm not sure where to check for the short. the wiring diagram here https://portal-diagnostov.com/en/2020/0 ... -diagrams/ shows a dkblue wire junction in the junction box on the left of the dash, but I have no diagram for this junction. Does anyone have a wiring diagram for the junction box to the left of the diagram?

[joatmon]

Looks like power comes from the ECU-IG 1 fuse, which, according to the diagram, only gets power when the ignition relay is closed. Perhaps the problem is further upstream. why would the ECU-IG 1 fuse get power, and why would the PCM send a signal to the cooling fan relay control to turn the fan on, if the ignition is off? When the ignition is off and fan is running, find and pull that ECU-IG 1 fuse. If that stops the fan, then problem is on the other side of the fuse, if it doesn't, then the problem is after the fuse

[Ginko]

Just double checked that before taking out the engine bay fusebox to find the right wire. The fan runs with the car off if regaurdless if the ECU-IG-1 fuse is in or not, so I think the problem is in the junction box. On the diagram the problem is upstream of pin 1 of the FAN 1 relay, I've checked and it's always hot if the battery is connected. I've found where the dkblue/blk wire leading from pin 1 goes to in the dashboard junction box, but that's where I'm stuck at now. would a short somewhere in that junction box lead to that line being hot all the time? even when the ECU-IG-1 fuse is out? I've inspected the fuse and it's fine, but I'm lost from here.

[andrewclaus]

Have you checked the relay itself? Try a bench test--should be open contacts out of the car, apply 12V to the coil terminals and contacts should close.

[Ginko]

yeah I've swaped out both the fan relay and the radiator fan control module. I've isolated the problem to the interior fusebox, so I ordered a used one and I'm swapping it out.