2004 c5 hdi 110 cooling fan woes FIXED and now running (pg 6 on) .

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wheeler
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Re: 2004 c5 hdi 110 cooling fan woes

Post by wheeler »

That’s correct on this system, the injection ECU triggers the high & low speeds but the A/C system triggers the mid speed operation via the BSI.
citroenxm
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Re: 2004 c5 hdi 110 cooling fan woes

Post by citroenxm »

I figured there was ecu commands in it as there's pleanty of connections to the ecu and bsm... I understand wiring. But no so good on actual operations. Mgmike has done a. Great job I can now look in one step further now and rule out relays..
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Re: 2004 c5 hdi 110 cooling fan woes

Post by citroenxm »

MGmike wrote:
15 Jul 2021, 22:45
I agree with Chris, it's a three speed fan determined by the relays and the dropper resistors.

1509 is a straight forward full speed controlled by the ECU when the coolant temp gets too high.
1508 is the slowest speed, again controlled by the ECU but probably when the a/c is on but it may actually be on all the time.
1548 is the stranger one as its controlled by the BSI, possibly when the a/c is on? However it gets it's main power feed from 1508 and therefore unless 1508 is activated it does nothing. That said, when both are activated they feed the motor via two resistors providing an intermediate speed.

I would concentrate on relay 1508 to start with... If you pull the relay and insert a bridge wire on 3 & 5 the fan should run at a low speed.
If it does... great you have a relay fault (note: is a special(ish) relay with a diode in to protect the ECU and must be replaced by one of the same type). If the motor doesn't run you need to check the wiring and resistor 1506. (let us know what the resistance measures at and we'll be able to work out what the operating voltage and current will be for each speed).

The big kicker here is you might still have a fan motor fault! You know the fan runs at full speed but you don't know what voltage is needed to run it at the lower speeds. Stiction in the motor could require more volts/amps to overcome than the resistor allows. To partly prove this, bridge pins 3 & 5 on both 1508 and 1514. Hopefully the motor will run but probably it won't be as fast as it should be.

If it runs you have two options
1, replace the fan
2, add another resistor in parallel with 1506 to overcome the stiction in the motor.

best of luck with it....
OK.. Has a play with this.. I put a short wire in 1508.. Fan run slow.. OK good.. So... Tried another relay.. No fan.. So swapped relays over with 1514 and the relay from 1508 works in 1514 relay socket so it's not a relay issue.. What I did find with the relay if I shorted pins 1 and 3 out the relay buzzes and the fan starts.. Solinoid 12v are on pins 1 and 2 but are lost when then rekay is pressed in so it's haveing a voltage drop from somewhere.. But that's all I can work out..
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Re: 2004 c5 hdi 110 cooling fan woes

Post by citroenxm »

Buggery poo.. I've upset something now. Lift pump only primes up now and won't run while engine is running.

Jeesus.. Wish I hadn't noticed the fans not working now.

And I've checked all bsm fuses..
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white exec
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Re: 2004 c5 hdi 110 cooling fan woes

Post by white exec »

From the circuit diagram, 1514 and 1509 can be swapped over, but 1508 needs to be in its proper place, because it's a 5-pin (changeover) relay.....the other two are just "makes". Check the relay sockets to make sure that the 5-pin one is in the socket with five lots of connections.
You could use 5-pin (changeover) relays in the other two sockets without a problem, as the unused connection will just get ignored. If obtaining new relays, 5-pin ones could work in all three places. Same as on XM.
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Re: 2004 c5 hdi 110 cooling fan woes

Post by ozvtr »

The commutator doesn't look so good in your photos. Did you clean between the segments? There should be a gap between the segments like you can see at the top and the bottom. The segments might be shorted out.
file.jpg
Typically the BSI runs the air con but the engine ECU runs the fan(s) and the compressor. This gives the engine ECU the power of veto over the air con. Like if the car hits a big hill and the engine is under load. But in this case the engine ECU runs the cooling fan low and high speed and the BSI runs medium speed. This appears to be the circuit diagram for the cooling system and not the air con (just saying). Connections to the high pressure line and the bus lines to the BSI are missing. So it looks like the there is no medium speed under normal conditions or the engine ECU has to "ask" the BSI for medium speed if the air con is NOT running? Bizarre

Edit: Oops, the high pressure line sensor IS there, it's the connection to the compressor that is missing
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Re: 2004 c5 hdi 110 cooling fan woes

Post by citroenxm »

citroenxm wrote:
17 Jul 2021, 12:00
Buggery poo.. I've upset something now. Lift pump only primes up now and won't run while engine is running.

Jeesus.. Wish I hadn't noticed the fans not working now.

And I've checked all bsm fuses..

I'm more concerned over a non running car now then a ran mot running. It's not a brush/comm issue from what I can now see..
MGmike
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Re: 2004 c5 hdi 110 cooling fan woes

Post by MGmike »

citroenxm wrote:
18 Jul 2021, 02:19
citroenxm wrote:
17 Jul 2021, 12:00
Buggery poo.. I've upset something now. Lift pump only primes up now and won't run while engine is running.

Jeesus.. Wish I hadn't noticed the fans not working now.

And I've checked all bsm fuses..

I'm more concerned over a non running car now then a ran mot running. It's not a brush/comm issue from what I can now see..
That's not good! It appears shorting pins 1 & 3 wasn't your best decision and I hope you haven't blown up your ECU!
Anyone got a lift pump wiring diagram to see if I can workout what may have happened?
MGmike
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Re: 2004 c5 hdi 110 cooling fan woes

Post by MGmike »

citroenxm wrote:
17 Jul 2021, 11:43

OK.. Has a play with this.. I put a short wire in 1508.. Fan run slow.. OK good.. So... Tried another relay.. No fan.. So swapped relays over with 1514 and the relay from 1508 works in 1514 relay socket so it's not a relay issue.. What I did find with the relay if I shorted pins 1 and 3 out the relay buzzes and the fan starts.. Solinoid 12v are on pins 1 and 2 but are lost when then rekay is pressed in so it's haveing a voltage drop from somewhere.. But that's all I can work out..
Setting aside the fuel pump issue for a min... when you linked 1508 was the a/c on or off?
Did you get the fan to run at two speeds eg with a/c off (lowest speed) a/c on (intermediate speed)?

On 1508 did you measure the coil 12v with your meter in pins 1&2 or pin 1 to a ground (e.g. car body) and then pin 2 to a ground? I'm guessing you were on pins 1&2.

OK, if you have 12v on pin 1 with the relay out but 0v with the relay in, you have a problem further up the supply line from the BSM. First you need to check the C150 wire back to pin 10 of the grey plug on the BSM and check the plug for any corrosion. However, I think the most likely issue is a relay inside the BSM and with a bit of luck it's common to the lift pump!
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Re: 2004 c5 hdi 110 cooling fan woes

Post by citroenxm »

All wires measured 0 ohm or no resistance when I did end to end checks. I don't mind swapping the ecu. As a stroke of luck there's and ecu and bsi on ebay for 40 quid. Also a fella on fb breaking a c5 too. So I can get an ecu fairly cheap. The other reason for wanting to swap the ecu is the ecu has had an ongoing issue with the cruise control redundant brake switch setting.. It won't release it despite again all wiring and new brake switches fitted so I'm dirt of keen to see if it's an ecu fault or something else though it can't be as wiring all checks out.

When I put the non working relay into the other black plug of the working relay the non working relay worked and it clicked.. The working relay didn't click on socket 1508..

Wben I bridged 1508 with engine off the fan came on. Sane results with engine running and the bridge.. After relay swapping that's when I found the coil for relay 1508 wasn't getting power it was only then I slipped with the probe and discovered what I had with the short..
wheeler
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Re: 2004 c5 hdi 110 cooling fan woes

Post by wheeler »

MGmike wrote:
18 Jul 2021, 07:35

That's not good! It appears shorting pins 1 & 3 wasn't your best decision and I hope you haven't blown up your ECU!
Anyone got a lift pump wiring diagram to see if I can workout what may have happened?
Which relay has had pins 1 & 3 shorted?
Have you checked all the fuses inside the car too?
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Re: 2004 c5 hdi 110 cooling fan woes

Post by citroenxm »

No. I ran out of energy yesterday.. I'll take the glove box out and check them today..

I don't. Mind an, ecu and bsi swap.. It. Might also solve the redundant brake switch not releasing In the ecu allowing the cruise to work. I've checked and fitted a new brake switch and it stays depressed and won't release.. It see the brake switch released.
MGmike
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Re: 2004 c5 hdi 110 cooling fan woes

Post by MGmike »

citroenxm wrote:
18 Jul 2021, 08:20
All wires measured 0 ohm or no resistance when I did end to end checks. I don't mind swapping the ecu. As a stroke of luck there's and ecu and bsi on ebay for 40 quid. Also a fella on fb breaking a c5 too. So I can get an ecu fairly cheap. The other reason for wanting to swap the ecu is the ecu has had an ongoing issue with the cruise control redundant brake switch setting.. It won't release it despite again all wiring and new brake switches fitted so I'm dirt of keen to see if it's an ecu fault or something else though it can't be as wiring all checks out.

When I put the non working relay into the other black plug of the working relay the non working relay worked and it clicked.. The working relay didn't click on socket 1508..

Wben I bridged 1508 with engine off the fan came on. Sane results with engine running and the bridge.. After relay swapping that's when I found the coil for relay 1508 wasn't getting power it was only then I slipped with the probe and discovered what I had with the short..
do not change the ECU and/or BSI until you are 100% certain of a fault in them! It's a big job with a lot of other things interlinked.

So, the short was accidental with the meter probe?
Hopefully no damage done to the ECU. Was the engine running at the time of the short? When did you discover it no longer runs?
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Re: 2004 c5 hdi 110 cooling fan woes

Post by citroenxm »

Yes engine was running and it stalled. If I lock the car then unlock it put key in the pump primes up and the car starts on the fuel that's primed up.. Then switching the ignition I just get the thud that, you hear.. No pump running.
I have. Swapped bsi before. You only need to swap the engine ecu and bsi and put your exsisting key. Blade into the matched key with the ecu and bsi.. Its not a hard process just fiddly at the bsi side.
Having the hdi starting and running diagram may well help us. The Haynes book has a typical one and that doesn't even show a petrol fuel pump. It concentrates more. On charging side.
wheeler
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Re: 2004 c5 hdi 110 cooling fan woes and now not running....

Post by wheeler »

Can you confirm what relay had pins 1 & 3 shorted?
What is your VIN to enable wiring diagram lookup?
Yes doing a BSI & ECU swap is not that a big deal, i would just advise making a printout or screen shots of the original BSI configuration first so the 'new' one can be configured to match.