Been noticing some pretty hot under the hood temps, although my dash gauge seems to be reading fine while driving in 65* weather.... the needle just slightly under the half-way point. I have two 10 ProForm fans hooked to a ground sensor @ 195* through a relay, using the all metal 3.0 radiator. I decided to run the fans via the IGN cicuit, so basically all the time, in an attempt to lower the under-hood temps. Here's the crazy thing, when I run them like this and turn the key to the IGN, the fans turn on, but my tach bounces up and down to about 50rpm, and my e-brake light is pulsing with the tach. I can only think that there is some sort of electrical interference. Being an 03 3.4 I know there is a lot of shielded stuff in the engine area and it has the ETCS, which I think can vaugely hear as a very high pitched sound in the engine with the key on IGN. I ran the circuit after the EFI relay, then before and the same thing is happening. Not only that, but the engine has a hard time starting when the fans are running. Anybody with a similar experience they solved? Wondering if I ran fan gnds directly to the battery would solve it. Bout ready to go mech....Thanks...D

 

Think it was a bad ground. Re-grounded the fans right to the battery and no more issues. The Gnd must have been traveling through the engine and back to the battery, interfering with another engine ground point for something.