Defender TD5 A/C Fan on with Ignition!

Raider td5 · Apr 8, 2019

My 2001 TD5 Defender's air conditioning fan turns on as soon as I switch on the ignition and keeps running even if I have the air condition off. And it only turns off about 5 seconds after the ignition has been turned off.

I have this vehicle from new, originally the fan only worked with either air conditioning or if the coolant temperature rose past the capabilities of the viscous fan.

Kindly advice where should I look to fix this?

FlyingPete · Apr 8, 2019

The fan relay uses a switched ground from the ECU to turn it on, and the relay positive comes from the main relay which is powered up by the ECU.Sounds like the output from the ECU is always at ground hence it's coming on all the time- the positive side switches off when the ECU shuts down hence the 5 second delay.

Could be:

Short circuit to ground on the fan control wire.
Faulty AC pressure switch giving a constant fan request to the ECU
Fault in the coolant temperature sensor wiring- the ECU then goes into a fail-safe mode and assumes the engine is always hot.

Defender TD5 A/C Fan on with Ignition!

Raider td5

Active Member

FlyingPete

Well-Known Member

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