1253h3 Coolant fan, temperature sensor ?

Hi everybody,

i have a problem with coolant fan..
Lexia is sayi p0485. (At low speed, the fan fails, but fails at high speed.)

I replaced the fan with a new one. However, the error warning has not passed.

1. Pink cable: Relays the relay.
2. Blue cable: ? I don't understand what this cord does. When disconnecting the cable, no change !
3. Yellow cable: The voltage changes according to the fan speed. When disconnecting the cable, the fan runs at full speed.

i wonder "1599B", "1540B" and "12--" what it is ? I want to test the cable and sensor.

The cable voltaj:

Motor stop, fan stop:
1. Pink: 0.2 V
2. Blue: 12.20 V
3. Yellow: 12.85 V

Motor run, fan stop:
1. Pink: 0.2 V
2. Blue: 13.57 V
3. Yellow: 14.30 V

Motor run, fan run slow
1. Pink: 4.5 V - 3.70 V - 3.10 V - 2.80 V .... ( changing by speed, by water tempature)
2. Blue: 13.45 V
3. Yellow: 14.30 V

Motor run, fan run fast
1. Pink: 8.00 V
2. Blue: 13.45 V
3. Yellow: 14.30 V

simuzer wrote: ↑Sun Oct 28, 2018 1:28 pm
i wonder "1599B", "1540B" and "12--" what it is ?

12-- looks like the Engine ECU (icon is an injector)

1599B is feedback from the fan to the engine ECU

1540B is a signal from the engine ECU to the fan controller.

Thanks a lot C3CAR. I understand now.

So, What should be the voltage of blue cable number 2?

I continuously measure 12-14 volts.

Is it possible that the cable battery is shorted to +12 volts or should there be a variable voltage?

Could it be?

At maximum speed feedback 0 volts
Minimum speed when feedback 12 volts
or vice versa.

simuzer wrote: ↑Tue Oct 30, 2018 6:58 am So, What should be the voltage of blue cable number 2?

I don't know.

If your blue wire (you marked as 2 in this picture)
is actually number 2 on the digram and is wire number 1599B then this feeds back to the ECU that the fan is running, by the looks of it.

But I don't know if you have correctly identified the wires by their numbers and the connector numbers.

You probably have 2 different voltages on 1599B depending if the fan is HIGH speed or LOW speed, but that is a guess.