407 coupé heater motor

[Jay-Bruce]

Hi, I'm resurrecting my 407 coupé 2.7v6 hdi - and noticed the heater motor now isn't blowing, could someone point me in the direction of where I'd find the blower motor ballast resistor / control module, and also give me a guide to getting the motor out, which I suspect is going to be a dash out job I'm hoping that if I can get onto the control module, I'd be able to put 12v direct to the motor, and get it started, so any useful advice on this endeavour would be much appreciated. Thanks in advance

[Jay-Bruce]

Ok, bit of an update, got a couple of hours on it this afternoon, with the glovebox out I was able to get a hand up and remove the heater motor wiring. Thick black and thick red on the outside, dainty wee purple and green/orange wires in the middle. Getting 12v+ across the red & black, I then metered the purple + green/orange wires, which gives me ~2.5v with fan switched off, and ~5v with fan at max, increasing incrementally as I go up through the steps on the fan speed control on the dashboard I'm guessing these are a sped control signal, and could even be a PWM signal that my meter isn't able to see as anything other than a simple DC voltage?

Since the control module seems to be working, I went to extricate the motor from the ventilation module. The motor twists about a 6th of a turn on a bayonet type catch not unlike an oversized bulb holder. However, there was a tonne of wiring and modules in its way, including a module labelled as "Azimuth Calculator" in french, which was stopping the motor getting past the fins of its fan. Once the azy calcy thingy was unbolted and moved aside, I was able to get the motor completely out of the heater box, but unable to get it out from the dashboard, as it was catching the bracket for the brake light switch. That bracket is welded to the "pedal box" but I was running out of light by the time I was trying to remove that. But I got far enough into that to see that the length of studs from the bulkhead along with the link shaft from the pedals on the right, master cylinder on the left, are boxing that in.ive removed the shaft from the left end where it connects to the master cylinder, later I'll remove it from the pedals in the drivers footwell. That should allow me to get the shaft far enough out of the road to get the left pedal box out to allow me to get the heater motor out.

On one hand the nature of the design necessitating dismantling and removal of the pedal boxes does make this a bit of a kerfuffle, and a needles one at that as shorter studs or through bolts into trap nuts would have allowed the pedal box to have come out easily. Then again, it's at least a positive that I am able to get the motor out without having to remove the dashboard. So yeah, it's an awkward sod of a job, but at least it is moving in the right direction.

[CitroJim]

Oh, what a pain

Thick black and thick red on the outside, dainty wee purple and green/orange wires in the middle. Getting 12v+ across the red & black, I then metered the purple + green/orange wires, which gives me ~2.5v with fan switched off, and ~5v with fan at max, increasing incrementally as I go up through the steps on the fan speed control on the dashboard I'm guessing these are a sped control signal, and could even be a PWM signal that my meter isn't able to see as anything other than a simple DC voltage?

Yep, that's spot-on... The control voltages look about right based on my experience with Xantia and XM blower regulators... It could be PWM but may also be straight variable DC.. Whatever, it's good enough to run the fan... The thick black and red are the high current feed wires... Blowers take a surprisingly high current - around 30A at full chat...

One thing to check is that the 12v you are seeing on the thick wires is there when the fan is trying to run as a high resistance in these high-current carriers might cause the volts to fall to zero under load whilst showing 12V on a high impedance test meter off-load (i.e. when the cables are unplugged from the blower).. This was a common Xantia fault due to high resistance in the (failing) ignition switch contacts...

The regulator transistors may be open-circuit... It'll be unusual if so as they normally go short-circuit and cause the blower to run at top speed at all settings..

Once you have the module in your hand it may be quite amenable to repair - as Xantia/XM ones are... Happy to advise...

[MattBLancs]

Wow that does sound a pig of a job!

I'll keep quiet about how much simpler it was to remove on my 406 Coupe. This was off the road from best part of ten years and blower motor seized up. I lubricated it and much to my surprise it then lived to play another day.

So if you do manage to wrestle it free, then there is hope that it's just stuck and would free off.

[Jay-Bruce]

It is a bit of a pig of a job, but like I said, I'm ever so glad that I'm not having to remove the dashboard to get it out.

The motor is on a forty amp fuse in the engine bay fuse box, #11, I'm glad the electrical signals I'm seeing at the plug are about right, as I haven't found the regulator/control module yet. I suspect that the regulator will be tucked into the base of the heater box and inaccessible without removing the dash + heater box. I really don't want to remove the heater box as it would entail breaking the AC pipework which is another headache recovering the gas etc. Don't say just break it and vent it, I'm too much of an environmentalist to do that sort of stunt.

I'll need to try Jim's suggestion of metering it's voltages when it's meant to be running.

[MattBLancs]

a needles one at that as shorter studs or through bolts into trap nuts would have allowed the pedal box to have come out easily.

Sounds like you are teetering on the edge of an "using the angle grinder inside the car" conundrum again


Apologies if I have missed it, but have you got to the point of extraction to the point at which you can try spinning the fan's impeller?

Wondering if you can get some oil "near enough" to the bearings in situ and give it a wiggle by hand to get it free. Stick some pictures up when you are next at it , I find the camera phone sometimes gives you a view from a vantage point your head doesn't fit - sometimes a Eureka moment lies on the resulting image!

[CitroJim]

You'll likely find the regulator hiding within the fan housing right opposite to where the plug plugs in... Often it's just under the fan blades so as to take advantage of some forced air cooling as the regulator runs very warm at certain fan speeds...

Good call on the fan being seized Matt A bit of penetrant will likely free it up, even a bit of WD-40, but then it'll be good to get some proper light oil in there to give it a bit of lasting lubrication... WD-40 will dry out quite rapidly..

Note that the fan is unlikely to be removable from the motor spindle successfully but often it's possible to get penetrant and lube into the bearing through the fan blades... The motor itself may not be amenable to disassembly either...

[MattBLancs]

viewtopic.php?t=61551
Another 407 with, in that case feeble, blower motor trouble. Talk of seizing up in here too.
(Googling, trying to find some decent pictures / removal tips!)

Yes think WD40 or penetrating oil first step. For me was bit of engine oil second stage - slight whiff of warm oil for a week or so, but then dissipated.

Yes I know I should use engine oil for this sort of thing. By oil can has some 10w40 part synth I'd no use for and most oiling jobs (garden gate etc) just need a bit of anything slippy as a substantial upgrade from nowt at all!

[CitroJim]

By oil can has some 10w40 part synth I'd no use for and most oiling jobs (garden gate etc) just need a bit of anything slippy as a substantial upgrade from nowt at all!

Absolutely yes, I see no problem in using 10W/40 on the blower bearings... As you say, better than nothing

I have a few litres of 5W/30 knocking about that has no use in my cars but perfect for the oil can and lubricating the lathe...

[MattBLancs]

I have a few litres of 5W/30 knocking about that has no use in my cars but perfect for the oil can and lubricating the lathe...

When I got the lathe I discovered there's a whole menagerie of special specific lubricants you're supposed to use "slideway oil" and the like.

I found that "ISO 32" is generally the right sort of stuff, so bought 5 litres of that to slap liberally on the lathe whenever I remember.

Have a litre bottle of cutting fluid (Machine Mart) that seems "fine" to my untrained eyes so that's squirted on bits I'm making

[CitroJim]

Have a litre bottle of cutting fluid (Machine Mart) that seems "fine" to my untrained eyes so that's squirted on bits I'm making

I've been known to use LHM as cutting fluid

[MattBLancs]

Have a litre bottle of cutting fluid (Machine Mart) that seems "fine" to my untrained eyes so that's squirted on bits I'm making

I've been known to use LHM as cutting fluid

I've heard those well into "proper Citroens" eventually pretty much default to it in all applications. I'll not ask you if you've bathed in it

[CitroJim]

Have a litre bottle of cutting fluid (Machine Mart) that seems "fine" to my untrained eyes so that's squirted on bits I'm making

I've been known to use LHM as cutting fluid

I've heard those well into "proper Citroens" eventually pretty much default to it in all applications. I'll not ask you if you've bathed in it

No, not quite but I've been very well showered in it a few times Matt A douche vert From these frequent showers I did discover that LHM is a wonderful hair conditioner and gives you the most softest and fluffiest hair It might even be a good cure for dandruff