Tallcolorado

So car began cranking over with no key in ignition. Will stop if I pull the pwr/trn relay(not sure what this controls). After doing some checking my fuel pump and cooling fan both also come on. Checking for voltage issues and found that once I remove ground from motor and check with meter I have 12v. So I'm at a loss of how the motor itself is getting voltage on it. Looking for suggestions on things to check...2011 hhr 2.2

donbrew

Has the ignition switch recall been done? https://www.chevyhhr.net/forums/gm-r...-status-50716/

Is there a certain time/circumstance? Fob in your pocket?

Tallcolorado

No fob. Does all the time now. And not sure on recall but I unhooked it and it still did it.

RJ_RS_SS_350

Unhooked what?

The battery + is connected to the starter.

If you click on the link that donbrew provided, you can check if your car has any outstanding recalls.

You could try swapping your powertrain relay with an identical known good relay. What relay# is this?

firemangeorge

Maybe clear up what you say it's doing.
Is it turning over(starter engaging) and starting the engine ? Or, is it just turning over continuously (starter) and NOT starting the engine ?

Oldblue

Possibly rodents chewing the wiring.
loose underhood fuse box halves.
And those mentioned

Tallcolorado

Constantly turning over, not starting, but fuel pump and cooling fan both also come on. I have unhooked harness for ignition switch and also removed the pwr wire for starter. When the starter still turned over without being hooked to battery that's when I knew to check for pwr on motor ground. So with body grounds removed from motor everything stops. But when checked motor now has 12v on its ground. Car ground is ok.

donbrew

OK, somebody has hooked the battery up backwards? Or at least shorted it. Who last touched the battery or any wiring.

The starter grounds by being bolted to the engine.

Oldblue

More likely the starter solenoid, has burnt , so have the starter bench tested at your local parts palace.

donbrew

How could the solenoid have an effect on the fuel pump and fan relays?

My thinking is that the signal from the ECM to the relays is ground normally. If you were to reverse the inputs to the fuse box the side of the relays that is supposed to be "always hot" would become "always ground" and the side that is supposed to be signal becomes "always hot". The only way I can see for the engine to become hot and the lead to the starter become ground is reversing the battery.