Engine Fan always on

[70Uglybird]

My Electric engine fan suddenly just started staying on with the key even when cold. I was in the vincinty of the temp switch wire when installing Hydroboost lines. How do I check the switch what can I expect to read at the wire to test signal.

I changed the relay out just in case that was it no change engine kicks on as soon as car is started.

[raustinss]

Check grounds?

[Schwartz Performance]

The temp sender is a ground. It switches internally to straight ground when it reaches the proper temp. Unhook your switch wire, check ground between it and the engine. If it reads 0 ohms or straight continuity, then it's the sender. Otherwise check the wire. It may be grounding out somewhere- pinched, etc.

-Dale