xantia HDI not charging and no aircon fan

[harryp]

Hi all, Have replaced camshaft and aux belts and renewed the positive battery harness. Car started and ran at tickover but charging light stayed on. Blipped the throttle and light went out. So far so good. Switched off and restarted, same thing again. Switched on aircon fan worked ok so switched off. From here on in, car will not charge and no aircon fan, but have heated rear screen and clock. Haynes wiring dia shows a non-referenced item 0004 which I have to presume supplies excitation for the alternator. Have checked all fuses in both fuse boxes and am beginning to pull hair - and I don't have a lot to pull!! Is 0004 a relay? If so which one, i.e. where is it located? Previously to Crank pulley problem, car was working fine. Would be very grateful for any help on this as I am stumped. Cheers, Harry.

[Peter.N.]

Either your alternator has failed or you have a bad connection to the small terminal on the alternator. Lack of the heater blower is related to this as it will only work when the battery is charging. Connect a meter across your battery, it should read about 14.4 volts if its charging OK, much less and it isn't, with the engine running connect a wire from the battery to the small alternator terminal, if it starts charging you have a bad connection somewhere between the warning lamp and the alternator, if it doesn't your alternator is u/s

Peter

[harryp]

peterN, thanks for response, will try......

[harryp]

Had previously checked voltages before posting. Batt Voltage is now down to 11.66 and exicitation voltage is 1.33 volts with engine running . Connecting a wire from battery to exict on alternator gives 14v or so (pulled down by battery) and all circuits seem to be working.(Thanks for the reminder, didn't know that fans will not work with no charge, thanks ) Back to the beginning..... The problem is no voltage to exicitation on alternator. What feeds it? Logically I must have dislodged something when moving fuse box and alternator lead but nothing is obvious in engine bay. I have no idea where the exic feed comes from and Haynes doesn't cover it..... Any ideas please so that I can trace back/forward? Regards, Harry

[Mandrake]

If you post a few details about your car I should be able to get you the correct charging related wiring diagrams for your car.

I'd need: RPO number, engine and gearbox types/codes (eg RFZ/RFX etc) hatch/estate, with/without abs. If you're not sure what they are PM me your VIN number and I can look up all the details on service.citroen.com and then find the right diagrams based on that.

[Mandrake]

Here's the starter/alternator wiring for your car:

https://dl.dropboxusercontent.com/u/782 ... nciple.pdf" onclick="window.open(this.href);return false;

https://dl.dropboxusercontent.com/u/782 ... lation.pdf" onclick="window.open(this.href);return false;

https://dl.dropboxusercontent.com/u/782 ... Wiring.pdf" onclick="window.open(this.href);return false;

Because the air conditioning system also connects to the exciter control wire (so could potentially cause a problem) here are the air conditioning diagrams as well:

https://dl.dropboxusercontent.com/u/782 ... nciple.pdf" onclick="window.open(this.href);return false;

https://dl.dropboxusercontent.com/u/782 ... lation.pdf" onclick="window.open(this.href);return false;

https://dl.dropboxusercontent.com/u/782 ... Wiring.pdf" onclick="window.open(this.href);return false;

Hope that's of some help

Mystery item 0004 is shown in the first diagram as the charging light on the dashboard - which is shunted by a resistor, together they provide enough current to "bootstrap" the alternator exciter line to get it to start charging.

Does the charge light still come on when you first turn on the key ?

[harryp]

yes charge light comes on with key, and of course stays on!

[harryp]

update on my problem! Looking over the diags provided by Mandrake (thanks again) it would appear that the problem may lie with the aircon ecu or feeds to etc. Would someone please tell me which one it is? There are two at the osf, one large, one small. Is it one of these, if so which? Sorry if this is a stupid question but I have never found a reference as to which is which!
Have had lower panel off by interior fuse box, checked all fuses and reseated all the relays on the panel. Ditto engine fuse box. Now need to check feeds to/from aircon ecu when I find it. Harry

[RichardW]

Harry

The AC ECU is under the dashboard somewhere.... the two at the front are the Engine ECU and the hydractive ECU - there is also the large brown double relay in that box. I don't think this will be your problem though. You've measured 1.3V at the exciter wire? Is that to earth? This is to be expected, there will be a voltage drop across the bulb, and then another, smaller one, across the field coils in the alternator. I suspect that the AC ECU and blower (as both seem to be connected to the exciter wire) are monitoring the volt difference between feed and earth across the exicter - if there is a difference then alternator not charging, if there isn't then alt charging and fan runs. If you disconnect the exciter wire to the alternator, does the light go out? What original fault did you correct, and what work did you do?

[addo]

The aircon ECU is mounted vertically (on a RHD car) between the evaporator section of the HVAC and the centre dash componentry. You release a plastic clip and slide it down after removing the passenger footwell top felt.

[Mandrake]

I would think that the air con ECU is a red herring in this situation - it should only monitor the exciter voltage, not affect it. (Although I guess a fault with the ECU could interfere)

What I'd try first is what Richard suggested - disconnect the exciter wire off the alternator and make sure that the charge light on the dashboard goes out.

Assuming it does, use a small automotive test light (of the incandescent screwdriver type) to connect from battery positive to the exciter terminal - check that this light lights up when the key is on but engine not running, and goes out when the engine running, and that the battery is then charging correctly.

Basically you're substituting the dashboard light with another light to rule out the light and wiring. If it works ok with the test light I'd focus on wiring or dashboard light, if it still doesn't work with the test light then I'd look towards the alternator...

Connecting battery positive directly to the exciter terminal is cheating because then the field coil (G in 1020) is driven directly by the battery rather than by the 2nd set of diodes in the alternator. (Eg there could be faulty diodes in the alternator)

[harryp]

Gentlemen, Thank you all for your time and trouble in providing assistance....
Tests

-exicitation wire on --ign on charging light on, no fan; engine running, charge light on, no fan.
-exicitation wire off-- ign on no charging light, fan comes on; engine running, no charge light, fan comes on.
Using 5watt bulb in series to exicitation terminal (cannot find anything smaller), ign on no charging light, fan comes on; engine running, no charge light, fan comes on.

The initial problem was the failure of the bonded crankshaft pulley!!! I then found the starter cable in the same state as a previous post's pictures and replaced it. I fear that I have disturbed some connections somewhere in moving engine fusebox to attach the 3 battery leads. Surely cannot be a coincidence that I have an alternator problem, as when the pulley gave up the ghost everything was working normally after the event. I've heard of Sod's law... but!
I wonder what is going to stop working when I do the brakes, cables ball joints and P bushes....
Kind Regards, Harry

[Mandrake]

If it won't charge with your 5 watt bulb feeding the exciter terminal it sounds like a faulty alternator, although I can't really see the connection to the other work that you've done.

Are you sure you haven't mixed up the main charging terminal and the exciter terminal on the alternator when you replaced the wiring ? Are all the connections on the alternator good ?

If the alternator has a one way roller clutch on the pulley (some do) is there any chance that has failed ?

[harryp]

Thankyou for your response.... Cannot really mix up connectors due to size difference and that main output lead will not fit into "well" for exciter cable. It charges with a wire to excit post from battery, so ruling out faulty alternator charging? I was under the impression that the feed from the lamp went via the aircon ECU and compared voltages from somewhere or other??? On earlier (1970's) vehicles in general there was a control pack in the alternator -( to prevent over charging), or an external voltage controller (1970's Renault), so seem logical that either of these conditions must apply, possibly the ecu providing the control???? I'm in the dark here lol. When the belts were off, oscillating the alt pulley by hand could feel it seemed well connected..
Speaking of sod's law, opened the drivers door window to make it easier to play with ignition - heavens opened, window will not go back up so looks like plastic lift bracket has broken - window not lifting anyway. Door now closed round a plastic sheet. I am getting fed up with this game. I keep re-reading the posts but nothing seems to make sense regarding the problem. With the exic lead off, something must be telling the aircon fan to come on as it's not charging, so again suspect connections or leads to/from the ecu. will try re-plugging the aircon ecu (when it's daylight and if I can find it) and whack the alt with a large hammer - if nothing else it will make me feel better, but then the above law says something will break. AARRRGGGGGGGG.

[harryp]

Hi all, Looking at the circuits provided by Mandrake, it looks like 0004 - also in Haynes - is a small cell shunted by a resistor and fed from f30. However one of the other diagrams (none in Haynes) shows the excitation feed coming from the aircon ecu pin7, which is subject to many feeds from sensors. What I don't understand is why a small current through a bulb will cause the ecu to switch on the fans, (but the current itself is obviously too small for it to regulate the alternator) whilst direct feed from battery to exic terminal is seen as a fault condition. The car has been off road without battery for 6-7 months... flat cell in 0004??... but voltage of 1.3 would approximate to a button cell???? does anyone know the workings of the aircon ecu? Pah, off to do the door window.