Bitron Unit for early Xantia

[xantia_v6]

I have fixed the links in citrojim's original post. I hope that helps you.

Here are the diagrams applicable to the early MK1 with A/C:

These first three are the A/C proper..


A/C Circuit



A/C harnesses


A/C Component Locations

These next three are for the engine cooling fans...


Cooling Fans Circuit


Cooling Fan Harnesses


Cooling fan Locations

Note how pivotal harness 10AV is

Hope they help nail the problem. My book has now completely fallen apart scanning those

[xantia_v6]

I note that you say that grounding pin 10 does not cause the fans to run at high speed, that indicates a faulty relay, or faulty/corroded connections to one of the relays.

[Cui Alex]

I note that you say that grounding pin 10 does not cause the fans to run at high speed, that indicates a faulty relay, or faulty/corroded connections to one of the relays.

Putting pin 10 to ground does not activate the fans, but I hear 2 "accessory" relays get excited.
Could it be that the fans don't start because the climate circuit is currently unloaded and does not give a consensus via the pressure switch? (I am restoring this car).

I had a look at the files you posted, but if I can't find the 3 photos on page 2 posted by Clogzz I can't find them.

Sorry, but I'm not an electrical expert.

[xantia_v6]

I can't replace the photos that clogzz posted, as they were on an external site and we don't have any backup of them.

When pin 19 is grounded, only the relays, fans, fuses and wiring involved, the A/C components have no effect (they are on the other side of the Bitron).
In high speed mode, each fan is fed by a separate fuse, one of which feeds the fans in low speed, so I think that only leaves a fault with the relays or wiring to the relays.

[Cui Alex]

I can't replace the photos that clogzz posted, as they were on an external site and we don't have any backup of them.

When pin 19 is grounded, only the relays, fans, fuses and wiring involved, the A/C components have no effect (they are on the other side of the Bitron).
In high speed mode, each fan is fed by a separate fuse, one of which feeds the fans in low speed, so I think that only leaves a fault with the relays or wiring to the relays.

Very interesting this observation!
I keep putting my head into it even though I've already checked everything.

One question, but should pin 1 and pin 10 be grounded simultaneously or individually?

individually:

pin 1 spins both fans slowly,

pin 10 energizes 2 relays but does not spin the fans.

at the same time:

While pin 1 is grounded and the fans turn slowly, I send pin 10 to ground:

one fan stops, the other starts spinning at maximum..


it's correct? Thank you.

[xantia_v6]

Good question.

In normal operation, pin 1 is grounded to make the fans run (both speeds), and pin 10 is grounded to switch to high speed.

The symptoms you describe would occur if the second fuse (BMF2 in the diagram) is blown, or the wire to it is broken. It will be a large 30A or 40A fuse, usually in a separate fuse holder near the battery.

[wheeler]

Hi everyone, my name is Alex.
I'm bringing this discussion back to life because my peugeot 106 GTI has the same 15-pin relay as this discussion.

I dont recall a Bitron box ever being fitted to a 106 for fan control, Are you sure this is not the injection relay you are looking at?
Do you have a pic of the unit & its location?
What year is it? Even better a VIN would help.

[xantia_v6]

The Bitron was probably only fitted with aircon, which would be very rare in the UK.

[Clogzz]

[wheeler]

The Bitron was probably only fitted with aircon, which would be very rare in the UK.

Ah, just noticed the OP's location.
Never seen a 106 or Saxo in the UK with A/C.

[Cui Alex]

After many attempts and having tried everything I could try, I decided to buy a new Briton box, as it is available on ebay for €40.
I'll let you know if I fix it, thank you all.

One question, I've seen several Birtrons with different codes, but what changes between one and the other since the pinout would seem the same?
For example on 106/saxo I found 4 different ones.

[xantia_v6]

There were some very early units that had a different single wire temperature sensor, and there were variations for different engine operating temperatures.

I think that your tests have already proven that the fault is in the relays, fuses or wiring.

Try testing for +12V on pin 3 of the high speed relay, the blue wire from the fuse in clogzz diagram.

[Cui Alex]

I would agree with you, except that as far as my personal skills are concerned I can't do more than this; therefore before tormenting you and asking you step by step what else to check, I preferred to buy a new unit and thus exclude it from any problems. In case this is not the problem, I am left with a spare unit which is a rare piece anyway.

I admit I'm not very good with schematics, this is what I found of the 106.
Do you notice substantial differences?

[xantia_v6]

I don't see the cooling fans on that diagram, but it has reminded me that I think that I found a diagram for a 106 with A/C for someone else a couple of years ago, I will see if I can find it again.

[Cui Alex]

Maybe this?