87350gtanj

hello, my drivers side coolant fan constantly runs as soon as I start the engine. I've tried switching the ecm ,relay, fan and even replaced the pigtail going to the relay and it still constantly runs I've even taken a test light to the pigtail and the only two wires that are getting power are the orange one and the tan one which from reading my factory service manual are the only two that are suppose to be getting power to them. So for now I have the relay unplugged the passenger side works as it should. Any help would be great

formula1LE

iTrader: (3)

I wonder if the temp switch is bad ie internally grounded short.

87350gtanj

replaced that too even unplugged it with motor running and fan was still on

Ransford2987

Is the negative of the relay grounded somewhere? Does it have a stock tune? Replacing the ECM wouldn't fix the issue unless it was internally grounded in the ECM, assuming of course that the memcal wasn't also replaced. I would guess it's grounded somewhere (probably the PO) if you unplugged the CTS and it stayed running, as that normally fails low, ~ -40*C.

87350gtanj

yes, it has two grounds and there both grounded to the same spot on the radiator support. And yes it has stock tune car just started doing out of no where one day.

Ransford2987

The fan power and the relay power are both grounded there? I thought the relay power was grounded via the ECM or the A/C pressure switch. I'll have to look at the diagram again. It might be the A/C pressure switch that failed on you. I don't know how those normally fail but it's worth a look to unplug it and see if the fan stops running.

87350gtanj

I've unplugged ac pressure switch with no change the only thing that I disconnected was the large ground wire from the rad support and that made it stop running although disconnecting that ground made it so the other fan didn't come on when it should have so I hooked it back up.

87350gtanj

From my understanding and also from what I've seen the car do the drivers side fan is operated/controlled by ecm and passenger side is controlled by fan switch someone else said it seems like a grounding problem I just don't know where to start.

greenyone

iTrader: (1)

It's my understanding that one of the fans is commanded on by the ECU and the other from the fan switch on the left side of the engine. I can't remember which is which though. But it does sound like you are grounding out somewhere. I know you said you unplugged the fan switch, but perhaps that wire is grounding out somewhere independent of the switch.

willexoIX

I would trace the ground wire from the relay of the fan that is constantly running, you will more than likely find a short to ground somewhere. Not the ground wire from the fan motor.