bdunegan

i have a 2009 p71, and the radiator cooling fan will not turn on at all. this is with and without a/c turned on. i unplugged the control module(mounted on the fan shroud) on the fan side. i jumped the fan directly to battery, and it runs. i unplugged module on other side, and have current to it. i then jumped both plugs together and fan runs. but when i jumped plugs together, ignition was off and i still had power. both plugs have only a black and a red wire, but plug on module side has a small wire just looped in and out of plug. i know fan runs and i know i have power to module, so am suspecting control module is bad. is this correct and is there any other thing i need to try.

CatSkinner

Could be, I'm sending a link of what should be the schematic for your fans. As noted in the schematic (and most of the relays controlled by the PCM, the PCM breaks the ground or neutral, not the hot. So find the neutral to the relay and short it to ground and your fan runs, it's your PCM.

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CatSkinner

Sorry, forgot the link.

http://ww2.justanswer.com/uploads/th...52_cooling.gif

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Prius repellant, just add gas.

bdunegan

wasnt necessarily thinking bad PCM but was leaning more toward the cooling fan motor relay that mounts to the fan shroud itself. it has a plug on one side from the pcm and another on the other side for the fan. i have power to the plug on the pcm side, but none coming through the control relay for the fan. i hook fan up direct and it runs so i know it is good. i jump wires(black and red) to both plugs and fan runs, just not getting any power through the relay to turn fan on. this is on a 2009 crown vic p71 with 76000 miles on it.

CatSkinner

If you know you're lighting the relay and the fans don't work, sounds like you need a new relay. Sorry to state the obvious.

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Prius repellant, just add gas.

Bajarider

Hello:
Check both the high speed and low speed relays before assuming the problem is the PCM. PCM's are expensive.

Since the fan doesn't run with the A/C on, first suspect one of the relays or wiring connectors, probably the high speed relay, then check ground circuits and connections between the PCM and relays (you have already determined that you have hot to the fan).

Just to be sure, I would also disconnect the coolant temp sensor. I THINK the fan should default with the sensor disconnected, it does on my '09 Mustang and '05 CV.

(Sorry to chime in so late on this, but I have been away from home and the internet for several weeks).