C4 Picasso Heater Resistor plug Melted AGAIN!

[ChrisPembs]

Afternoon All

OK, this car is driving me nuts, mechanically it is great, everything else pffffffff! About 12 months ago the cabin heater in the front would not turn off, researched it, bought a new resistor, the plug to the resistor had melted so managed to source a new one and spliced that in, fast forward 6 months it had begun to melt again, the connector that is, the fan was labouring a bit so bought a second hand unit off Ebay complete with resistor and plug, spliced in the new plug, fitted the new fan all was fine, until last week, fan stopped working so popped my head under the dash and the damned plug has melted again! Fan is OK this time so going to purchase another new resistor and have spare plugs from my old fan undamaged but why might this keep happening? It is of course drawing too much current from somewhere but any ideas where that might be? Presuming there has to be a short somewhere, had a good look at the loom today and there is nothing obvious sadly so can someone help me understand how this all works so I can begin to figure out why this is happening pretty please

Thanks in advance.

[GiveMeABreak]

Are we talking about the same thing here - I can't see how you can splice this in:

This is the blower control module. This is usually attached to the blower motor itself.

The other blower control module is for the additional blower and is completely different

[Sloppysod]

Hi Chris, went through similar problem with Wife's Corsa last year, two new resistors and one harness. I ended up replacing the fan motor, I think the motor bearings were starting to sieze, not much but just enough.
I may be wrong, I have been once before, but if the Picasso system is similar then the fan motor will have moist air blowing around it.
Good luck....

[ChrisPembs]

Hey, how you doing? Thanks for the reply, yes this thing, it seems to be commonly known on Ebay as a resistor hence my use of that term, there is a connector that goes from this to the blower itself that one is fine, the one that keeps melting is I presume a power feed connector that comes from the loom and attaches to this control module, the exact same connector as the one that goes from this to the blower if that helps identify it, every time it melts the connector and also the connection point on this control module, did think it was something to do with the blower itself last time so replaced the whole lot, blower "fan", control module and the melted connector on the loom for the car but same thing has happened again.

[GiveMeABreak]

Ok, so these can be separate if not fitted directly to the Blower Motor.

I can only suggest parts quality as a possible issue - it's well known aftermarket blower control modules can be of terrible quality.

[ChrisPembs]

I would think the same but the original factory fitted did this and the genuine second hand one I fitted 6 months ago with the second hand blower motor has now done the same as well, they do separate easily 3 screws from memory, commands from the climate control panel are they sent to the BSI and then onto the blower module from there? I wonder if it could be an overload issue, I always have air con on and also always have rear blowers on controlled via the climate control panel and fan speed is usually always set to level 3 or 4, even though they are all separate systems do you think that could be an issue? It is designed to run this way but not sure of for extended periods or not?

Am at a loss, whilst inspecting and moving the connector around today it properly shorted but no fuse blew, smoke, micro fire type scenario for a couple of seconds before I managed to disconnect the connector from the control module but if fell apart leaving one pin behind in the module itself, could do with sorting it properly really, still having boot handle issues as well although that is now intermittent and "ABS, ESP, Parking brake not working" fault, again intermittent, electrical gremlins ughhhhhhh

AS an after thought, where could I get electrical diagrams from for this system with voltages so I can see what it is pulling and compare to what it should be pulling?

[Paul-R]

Two thoughts on this.

Is the motor sticking slightly? This could cause a higher than normal current draw.

Is the fuse the correct rating? Someone might have fitted a higher rated fuse because the damn thing kept blowing!

EDIT

A third thought. Does the system have a pollen filter? If this gets choked this can cause the motor to work harder than normal. The pollen filters are frequently overlooked in servicing.

[ChrisPembs]

Hey, thanks for the reply The old motor was a bit sticky and noisy which is why I replaced it with a second hand one last time, the motor in there now is virtually silent, well apart from the noise of air of course but nothing that should not be there, fuse I will check in the morning, it does indeed have a pollen filter that I have not changed on its last 3 services, I cannot imagine the guy who owned it before me changed it he had it for errrrr 2 years, before that it was a 1 owner car always serviced at Citroen so I would hop they would have replaced it so I can say the pollen filter has to be at least 5 years old at this stage, I did buy a carbon one that is in the errrr shed ha ha ha just never got around to figuring out where the filter housing is, definitely worth changing, thank you Will give it a try when the new control module arrives and see what happens.

[ChrisPembs]

Hi Chris, went through similar problem with Wife's Corsa last year, two new resistors and one harness. I ended up replacing the fan motor, I think the motor bearings were starting to sieze, not much but just enough.
I may be wrong, I have been once before, but if the Picasso system is similar then the fan motor will have moist air blowing around it.
Good luck....

Hey Stu thanks for the reply The original fan motor was noisy so did replace it 6 months ago with a genuine second hand one when I did the resistor last, the motor that is in there now is silent apart from the noise of air of course.

[MattBLancs]

Sorry if you have but just not mentioned it -

Have you tried lubricating the fan motor bearings?

If they "all end up a bit stiff" with age, then a second hand one may be equally restricted. I managed to get my 406 Coupe's blower motor fan back running again (was off the road, parked outside for best part of ten years) with a bit of disassembly and oil fed to the motor bearings

[ChrisPembs]

Sorry if you have but just not mentioned it -

Have you tried lubricating the fan motor bearings?

If they "all end up a bit stiff" with age, then a second hand one may be equally restricted. I managed to get my 406 Coupe's blower motor fan back running again (was off the road, parked outside for best part of ten years) with a bit of disassembly and oil feed to the motor bearings

Hey, thanks for the reply and tip Will take it out completely when the new control module arrives and have a proper look, it did move really very freely when I installed it but no harm in greasing it up, thanks

[MattBLancs]

The only slight potential harm is being unable to get away from a slight whiff of 10w40 in my experience!
Might have been a bit generous in my application, but equally mine was stuck fast initially! So was an "end it or mend it" task

It went away after about a fortnight of use

[ChrisPembs]

The only slight potential harm is being unable to get away from a slight whiff of 10w40 in my experience!
Might have been a bit generous in my application, but equally mine was stuck fast initially! So was an "end it or mend it" task

It went away after about a fortnight of use

Beats the smell of molten plastic ha ha ha

[ChrisPembs]

Done a bit more research and took an autodata trial so I can access the electrical diagrams, the power side of things looks pretty simple, well, assuming I am fully understanding the diagram anyway.......

40 amp fuse feeds a blower motor relay which then feeds the blower control module which then feeds the blower motor, it seems there are 2 relays in the mix 1 which takes power directly from the 40 amp fuse and then sends it onto the blower motor relay, I wonder if any of these have been changed at some stage for incorrect relays? The fault seems to be drawing too much power, if the wrong relay has been used that may account for that but would a failing relay cause a spike? Not an electrical expert but to my knowledge a relay is just a switch so not sure if it was in a failing state if that could somehow cause this melting of the plug?

[MattBLancs]

As you say a relay is just a switch, so should not be able to supply more or less power.

Either:
- circuit is drawing more current than normal (e.g. fan bit seized, or something else causing it to work harder and so need more current. Alternatively something else in the circuit (including potentially the wiring etc) is high resistance and so is also turning current into heat - hence overloading the plug.

- possibly in conjunction with the above, bigger fuse than designed has been installed, so more current is allowed through without it blowing, hence overloading the plug.

- plug and or socket tarnished, damaged (or even poorly designed or made) is causing high resistance at this connection, so heat as a result.