electric Fans

[87gmc]

Can efilive flashscan actually activate the wire on a 99 Ls1 truck? I have heard of it and thinking of installing ls1 fans on my z71.

[John Skiba]

Hook up a test light and go driving.

[87gmc]

ok if i do the test light is fan activator a positive or negative wire.

[Dirk Diggler]

Doesnt matter once there is a path to ground the light will light. Bulbs have no polarity unless its an LED

[Blacky]

Hook up a test light and go driving.

Or just use the bidirectional controls to command the low and high speed fans relays on/off.
Whether or not the PCM is actually calibrated to command the electric fans or not is a different story.
Paul

[GMPX]

PCM switches the outputs to ground.
With relays (or test lights) one side must go to +12V, the PCM will switch the other side to Ground to turn it on.

Cheers,
Ross

[Telco]

Blast from the past! Hi again folks., Finally got my truck running again, and I just installed a set of 2006 Silverado on my 2000 Silverado with the fans connected to the computer. But, it doesn't work. One side is connected to the computer, the other is connected to ground. After reading this, can I assume that I need to have 12V instead of ground connected to the relay? Thanks.

[Telco]

Disregard, found the problem thanks to stroker97k1500 over at PacAudio. I'll be connecting 12V to the relay instead of ground tomorrow, then the computer should be able to control things. Embarassing, but the important thing is that I'll have it working as soon as I fix this wiring snafu.

[Lextech]

How do led lights different from normal bulbs?

L.E.D. (Light Emitting Diode) A diode is kind of like an electrical check valve. Electricity will only flow one way through them and won't flow if they are hooked backwards. So, If you have power and ground hooked up correctly it will light up. If it is hooked up backwards it will not light up.

Jeff

[joecar]

Also, if the LED does not already have a series resistor, you have to add one to limit the current thru the LED.