Radiator Fan SOMETIMES do not turns on and it is filling and dropping temp lights on the dash and beeping an alarm

frankoprifti wrote: ↑Fri Jan 22, 2021 7:39 am I want to install a switch that turns the fan on manually for the times that the coolant temperature switch doesnt do its job. So i dont have to open the hood and disconnect and reconnect the wires to make it work.

Ozvtr wrote: ↑Fri Jan 22, 2021 8:40 pm

frankoprifti wrote: ↑Fri Jan 22, 2021 7:39 am I want to install a switch that turns the fan on manually for the times that the coolant temperature switch doesnt do its job. So i dont have to open the hood and disconnect and reconnect the wires to make it work.

It depends if you have air conditioning or not.

If you have air conditioning there is a grey plug on the fan shroud. Pin 1 (yellow wire) controls the fan. 12v turns the fan off, open circuit causes it run.

If you don't have air conditioning, that's a bit harder. The relay is located behind the left hand head light. You can run 12V directly to the fan motor pink (I think it's pink) wire. This method switches a fair bit of current so your switch and wires need to handle that.

Arfur Dent wrote: ↑Tue Jan 19, 2021 9:44 am

frankoprifti wrote: ↑Tue Jan 19, 2021 8:42 am Hey there, I have a 2003 C3 with Petrol+LPG. Most of the time the fan runs completely fine. But sometimes the temperature signals on the dashboard start lighting and dropping down to 3 level like an alarm to show that its not working, its not overheating as I am understanding but just seeing this signal and a little beep for alarm, then i have to open the hood disconnect the cable that has two thick wires and reconect them again and it start working. What am i dealing with here? Hoping someone can help me!

Hello

Is the level of the coolant in the coolant container between the mini and maxi marks when the engine is cold?



Citroen_C3-coolant-level.jpg

Ozvtr wrote: ↑Sat Jan 23, 2021 2:09 am The fan output is modulated (turned on and off) by the control wire. This control wire comes from the engine ECU. Normally it's high (+12V). But when the engine ECU wants to control the fan (variable speed) this line oscillates between +12 and 0 Volts. If the engine ECU wants the fan on full speed this line goes low (0V). 0Volts is either connected to the chassis OR open circuit (disconnected). To answer you question; disconnecting the line will turn the fan on, but re-connecting it just puts it back under the engine ECU control. So if you just want control of turning the fan ON then yes, put in a switch that opens and closes this wire. If you want the fan to remain off, no matter what, then you need to connect this line to +12V. So if you want FULL control over the fan then you will need a 3 position switch (fan on, fan off and automatic). As I said I don't recommend turning off the fan (connecting it to +12V) for the reasons I outlined in the previous post, but It's your choice.
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Wire 1 (green/yellow) is battery return to negative (Chassis ground/0v).
Wire 2 (white) is fused power from the battery (+12V).
Wire 3 (grey) fan enable (from BSM/fuse box in the engine bay). This turns the fan power off/on when the engine is shut down/started up.
Wire 4 (yellow) Fan ECU "good" line. Tells the engine ECU that the fan controller is working correctly. If the fan is not working the engine ECU will not allow the air conditioning compressor to work.
Wire 5 (mauve) control line. From the engine ECU. This works as outlined above. This is the one you need to put your switch in.
This arrangement ONlY works if the fan controller is functioning correctly. If the fan speed controller is faulty, this may not work. So this is not a guaranteed work-around if your speed controller goes faulty. That's just for general information and may not apply in this situation.
Once again, I don't recommend this course of action but here is all the information that you need.
This information is given "in good faith" but it is understood that you are responsible for the serviceability of your car and not this forum.
Good luck.