pdexta

iTrader: (17)

Driving home today I noticed my car getting a little warm when stopped. Came home, checked the fan and it wasn't coming on.

I hit the AC and that fan came on. I swapped the relays and the AC fan still worked, so both relays are good. I connected the fan directly to a battery and the fan comes on. I checked megasquirt and it's reading the correct water temps. I did swap the radiator a few weeks ago, but it's worked fine since then.

Any idea what's broke or how to fix it?

Midtenn

iTrader: (15)

Short in the signal wire to the relay?

pdexta

iTrader: (17)

The "maybe a random wire fell in half somewhere" theory was about all I've been able to come up with too

Thanks for the input. I was hoping there was something obvious I missed. Forgot to mention in the first post, fan fuse in the engine bay looks fine too.

Reverant

iTrader: (10)

Are both fans on when you press the A/C button?

pdexta

iTrader: (17)

No, just the passenger side fan.

Reverant

iTrader: (10)

1) If you ground the fan relay pin, does the relay and fan activate?
2) How are the fan circuits inside the MS built?

vortexblue

Subscribing to this thread.
I have a off-the-shelf MS3 that will turn the fan on, but it seems to be on a switched circuit. I'm wondering if I'd be better off to mod the MS or just simply run constant power to my fan relay.

Braineack

iTrader: (62)

well it's possible the main fan is dead. ground TFA and GND in the diagnostics box to confirm the relay/fan is still working

who built it? did i? what circuit is the fan output going to through? do your software settings reflect this?

this isn't hard.

Reverant

iTrader: (10)

Per the first post, he swapped relays with the A/C fan, and the A/C fan still worked. He also applied battery power to the fan and it worked. So both the fans and the relay are ok - something is wrong either with the wiring (easy to diagnose in this case where the fan does not work, period) or with the MS fan relay circuit.

Braineack

iTrader: (62)

or a parameter not turning on the correct output...

Roo

happened on my uncles Miata.

he ended up wiring everything with a manual switch (was tired of trying to chase down the real problem).

Vashthestampede

iTrader: (17)

I had a problem with my fans (wired together, no AC) and it turned out to be the connection at the thermostat.