Keith Yee

Hello Everyone,

Ever since I replaced my exhaust manifolds with headers my coolant fan starts up when my engine starts. The fan normally turns on at 220 degrees. I know when i replaced my headers, I broke off the coolant fan switch and connector on the pass side of the head because it was old and brittle.

I replaced the coolant fan switch and connector on the pass side of the head with a new one from Napa. I also replace the coolant temp sensor which is located in front of the intake manifold. I also checked the fan relays next to the batteries and it all works well.

So i did that and I replaced one of the fan relay connectors as well.
So I still can't resolve my issue. My fan still starts up as soon as start my motor.
What else do I have to check? thanks!

87 Iroc Z 350 L98 TPI

jimm413

1st fan or secondary. Secondary closest to the battery side is for the AC and the fan switch is by the starter.(cooling fan switch go for a GM)

Keith Yee

The first fan, drivers side

phasevariance

Sounds like it could be grounding out somewhere. Trace the wire to the harness and see if it's frayed near anything metal

henryd3

iTrader: (128)

Yeah, the fan relays are actuated by the green with white stripe wire getting grounded. Either by the ECM for the driver side or fan switch or A/C on for the other one. If that wire melted or is getting grounded somewhere fan is always on with key on.Follow that wire from the relay back and check for that