Heater blower failure

[davidandpaula]

Tippy Yahoo
Part arrived, connected it up, fan motor working again.

Now I have to put some old clothes on and do the crawling around to put the York screw back in and replace the dash panel I took off to see what I was doing.

David

[bill sutton]

Hi all, just checked the voltage at the connectors, 12v and earth on the two pin plug, 12v and earth on the middle two pins of the six pin connector, 12v on the control feed on the outer pin but the other pin shows 0.3 v the two pins on the other side of the central 12v and earth pins (which are a larger gauge) have no wires connected, so only two control wires not 4. I am guessing that the motor is pants as the resistor pack is showing signs of life and the LCD is fully functioning, including the air flow controls and temperature.
which pins do I feed a direct 12v current down to test the motor in situ? I don't want to get it wrong as there's enough going wrong at present without me shorting more things out!!!!

[davidandpaula]

Bill,

I have not been able to pick up from the posts which type of heater you have.

Is it a climate control? Little fan symbol shows 8 speeds.
Is it a manual type with a 3 or 4 position "click" switch.

Have just fixed our climate control heater last week and when I checked the plugs I got various voltages on the pins.

If the big fuse under the bonnet is good you get voltage on the 2 pin connector. If the panel with the controls etc works and you can change fan speed and see the fan symbol change then the fuse that controls that is okay ( that fuse in in the glovebox).

I think the 2 pin plug will show 12V and then a voltage that varies depending on the speed selected.

Does the fan blower work when you select DEMIST mode or full speed? If it does then the you will have a "Click" type control and full speed and demist bypass the resistor pack.

David

[bill sutton]

Does the fan blower work when you select DEMIST mode or full speed?

No the blower does not at all, but everything else does (temp/direction/ac)

Is it a climate control? Little fan symbol shows 8 speeds.

Yes.

Will try another BSI reboot procedure just in case, but I'm guessing if there's a voltage on the two pin plug, then the motor should be turning?

[davidandpaula]

Bill,

For the 2 pin plug I think what you called the earth is in fact the output to the fan motor. Check the resistance to earth not the voltage. Applying a low voltage briefly to that pin of the plug should get a reaction from the motor if it is okay. If so the problem is the "resistor" pack.
The 6 pin plug has 12v and earth and the signal goes to the 4 outer pins. Should get a combination of voltages at these pins depending on what speed is selected.

David

[bill sutton]

The 6 pin plug has 12v and earth and the signal goes to the 4 outer pins. Should get a combination of voltages at these pins depending on what speed is selected.

This is where I am getting confused, as the plug has 6 pins, two large gauge in the middle and two pairs of outer pins (smaller gauge), but only two of the outer pins are wired to anything.

And if I understand this correctly

For the 2 pin plug I think what you called the earth is in fact the output to the fan motor.

So if I bridge the two pins, 12v+ve to Earth (motor feed) the motor should run flat out i.e without resistance? with ignition on of course.

Sorry if this sounds technically inept, but I'm more of a spanner man myself

[davidandpaula]

I am a bit more careful than that. I would try a 1.5 v torch battery and apply the voltage between body earth and the non 12v pin on the 2 pin connector plug.

As for the 6 pin connector you say only 2 wires are going to this one?

I have attached some photos of the unit I replaced with its covers removed so you can see the sockets and some of the surface mount components.

David

[bill sutton]

As for the 6 pin connector you say only 2 wires are going to this one?

Sorry, only two of the outer pins are connected, the two central pins are also connected. This tallies with the Haynes wiring diagram which also has 4 wires shown. Why fit a 6 pin connector if you only need 4 of them I'll never know, add it to the list of Citroen conundrums.

I would try a 1.5 v torch battery

Will 1.5v even move the motor? (assuming it does still move)

[davidandpaula]

As I say I am very cautious. Rather than risking a straight connection of the 2 pins in the good old days when I was teaching science I would have grabbed one of the big wire wound variable resistance packs from the science lab and started with lots of resistance ( effectively mimicking what the "resistor pack" does in the circuit).

When the fan motor stopped working I did not want to spend weeks waiting on parts delivery all the way from UK so I took a chance the "resistor pack" was the problem and ordered one. It worked as soon as I plugged it in. At the time I ordered it I had not taken it apart so did not realize that it was not in fact a cluster of resistors but actually a solid state circuit.

Just crawled under the dash again and yes, you are correct looke like 12V and Earth to the centre 2 pins and then 2 wires to the outer smaller pins at the end away from the 2 pin connector.

As best I can make out from the circuit board ( allowing for it being double sided ) the pins look to be
2 pin connector
Motor
12V
6 pin connector
not use on mine but has circuitry
not use on min but has circuitry
12V
Earth
Signal ground
Signal active

If you have a spare fuse ( 40amp under bonnet) then maybe you could try just a quick connecting of the 2 pin connector. Have you looked for a new "Resistor pack" on eBay to see what it will cost, the items have pictures and often a model checking link to identify the correct one. May even be readily available from a Citroen dealer ( not carried in stock here in Aus so we always will have a wait when getting the dealers to do the repairs.

David

[davidandpaula]

The unit I got was also marked as suitable for Renault and Peugot so the extra pins may be used on other makes and other Citroen models.