Bitron Unit for early Xantia

[xantia_v6]

Yes, that is the diagram for the cooling fans, but it appears to have an error, as the circuit as drawn cannot connect the motors in series for low speed.

I think that the wire shown connected to pin 3 of relay 1504 is actually connected to pin 5 and vice versa. If that change is made to the diagram, then at slow speed, both fans are fed by fuse F5, and at high speed, motor 1512 is fed by F5 and motor 1511 is fed by F3.

[xantia_v6]

I expect that the error is just on the diagram, not in the wiring of your car, but I do know of one case where PSA built cars with incorrect wiring based on an error in the diagram.

[Cui Alex]

Without going too far into the merits of the wiring, in my opinion it would be easier if I could understand, when the sensor gives consent for the fans to turn on on pins 7 and 14, what happens to the Bitron box.

I could give the signal with a potentiometer, so as to be able to make tests.

However, I don't know exactly what happens, if it opens or closes some pins, and if depending on the resistance (and therefore on the heat of the water) the Bitron does different things for high and low speed.

And if the air conditioning fan is driven by the climate control or by the Bitron itself.

[xantia_v6]

If you unplug the Bitron sensor on the engine, it should cause the radiator fans to run at high speed and bring on the temperature warning light on the dashboard.

The in-car blower is not connected to the Bitron, it is either controlled by the A/C ECU, or directly by the blower speed switch on the dashboard (depends on the specification of the car).

[Cui Alex]

Hello everyone, Finally, after many attempts I solved the problem.
2/3 contacts were broken or partially broken inside the connection plug between the wiring and the Briton box.
Not in the contact pins, but right inside the plug, I had to break the rubber which was obviously rotten, but I finally reached the conclusion... (do you know where I can buy a new plug?)

I leave below the information that I was able to understand based on the diagrams in my possession, I hope it can help someone.
I remember that I own a Peugeot 106 with a 2-pin temperature sensor, but I think the differences are minimal compared to the Xantia.

The system is based on:
Bitron;
2 5pin relays called "1502" and "1504";
1 4 pin relay called "1503";
1 radiator fan called "1511" + 1 radiator fan called "1512".


PINNOUT:

Bitron:
1: pin 85 "1503" (Ground);
4: permanent +12V (current passes through 2 fuses);
7: Pin1 temperature sensor;
8: Ground;
10: Pin 85 (ground) of "1502", Pin 85 (ground) of "1504";
14: Pin2 temperature sensor;
15: +12V via starter lock (through fuse), Pin 86 (signal) of "1502", Pin 86 (signal) of "1504".

1502:
87a: 87b of 1504
87b: Ground, Grond 1511
30: +12V 1511
85: Pin10 Bitron, 85 of 1504
86: +12V via starter lock and fuse, 86 of 1504, Pin15 Briton.

1504:
30: +12V permanent (through fuse)
87a: Power 1511

1503:
86+30: +12v permanent (via fuse)
85: Pin1 Bitron
87: Power 1512


1511:
Gnd, 87b 1502
87a of 1504

1512:
87b of 1503
30 of 1502

Thank you all for your help.


Alex.

[CitroJim]

Excellent! Good work Alex