I'm not very good when it comes to more than the basic electrical concepts. I have a Mark 8 fan installed installed in my chevelle. I have it set up so when my temp reaches 190 or so the fan turns on and turns off at 170 or so. The only problem I see with this is that the fan always runs at full speed. Is there a way to set it up so I can run it at, say, 1/3 speed when it hits 190, 2/3 speed when it hits 200, and full speed when it hits 210? (just an example). It's just too d@mn loud!

Could this be done by splicing the power wire into 3 and having resistors on each wire and then hooked up to relays... then having each relay come on at a designated temp? I know it would take 3 temp sensors, or a staged temp sensor (if it exists), but is it possible? I'm not sure how resistors work.

I also wouldn't mind if I had it on a 3-way toggle switch so that it would still turn on at the designated temp, but I can adjust how fast the fan spins. Is that possible?

Any advice/info would be great.

Anything is possible but wondering if a variable speed control out of a more modern car might be a thought. Haven't played with them before and don't have a schematic to see if something like that is feasable. Just a thought. Maybe someone else..

That is supposed to be a 2-speed fan. Try connecting power to the middle terminal instead of the outside terminal.

Peter

I wore out the brushes on a Mark 8 a while back. I had to take the motor apart to diagnose the problem. The middle terminal on this motor wasn't connected to anything. Just a dummy.

May not be true for all Mark 8 fans, but it was on mine. I mention this because I'd hate to see people freak out if nothing happens when they power up the middle terminal. It doesn't necessarily mean that there's a problem.