Powerstage Part Numbers
 

Hello everyone,
1994 850 GLT 20v ECC
I have been trying to source a powerstage for my car for over a year now but I simply cannot find one with my part number 9144355 W409 99A04461. I have tried a few places in London but i've had no luck.
My question is I have seen some on a auction site and the power stages look identical but the electrical connections are opposite I assume for LHD vehicles. The part numbers are 9166694 & 9134932. Any chance these could be made to work on my car? or is it more complicated?
It's chilly now and I cannot continue to ask my wife to bring a hot water bottle each time we use the car.
Many thanks for any advice in advance
Andre

Powerstage? Never heard of one of them before.
However those part numbers bring up a blower resistor pack.
You should be able to pick up either with little difficulty.
Have you tried Volvo ?
Give Frf motors in Swansea a call

No idea what a Powerstage is either, Electricity doesn't worry about part numbers. I can tell you a resistor is a resistor. Provided you find one large enough to deal with the current, once you have its value it's possible to put anything in. - the Volvo item I've seen pix of has a heat-sink. ie it's a power resistor able to deal with large loads.

If you can't get one, you being in 'Laahndan', this plan involves going 'North of Watford'. Can you cope? If all else fails a drive out to Wyboston to see Barry in the stix will see what you're after, and all for a deep sea-diver. These days, out here, we manage electricity.

Hi Andre, welcome to the forum.

IIRC, the '93/'94 cars can be a bit awkward in that Volvo seemed to be trying different solutions before settling on a standard one - so many parts are unique to those years. It is further confounded by Volvo using different part numbers for the same part (!)

As Rudi suggested, give FRF at Swansea a call - they are very helpful when you can get hold of them - but be prepared to be very patient as they are very very busy. I'd suggest that you have you reg number and VIN to hand, just in case they can't recall the VIN from your reg - the VIN may be needed for part number changeover points.

NB I have heard of the resistor pack being referred to as a powerstage - its a US terminology not frequently used over here, hence it being lost in translation :D

Good luck!

Thank you ALL so much for replying.

I think this started with me checking the DTC codes when the blower packed up. It was throwing 419 so I checked my Haynes which indicated 'Faulty diagnostic signal from blower fan power stage' and iirc 418 is 'No control signal to blower fan power stage'. After some web searching I discovered it was the resistor pack which apparantly, I read somewhere, is a basic chopper circuit.
I understand there is constant 12v on the thick blue wire and the power stage (resistor) varies the ground. Iirc a oscilloscope is needed to measure the digital signal from the head unit which is way out of my league. I have read many posts where the mosfet has been replaced successfully and some posts with equal failures. Since there is 12v permanently hot all the time (key out) I am scared to mess around replacing mosfets for fear of a fire.

I called Doves (Volvo dealership, Croydon) and was told the part number is now discontinued and my best bet was to search a salvage yard. Most scrap dealers around my end have closed (price of land) and the few I went to have no 850's.

I travel to Dunstable a few times a year.

Is Frf in Swansea a main dealer?

I am swaying towards buying a second hand unit on ebay and somehow making it fit.....thanks Rolling Thunder I was thinking the parts are similar with the only difference being lhd and rhd but happy to take a punt at £30.

Sadly, I only ever focus on this problem when the cold days set in.

Thanks again
Andre

We're at the point with these cars where parts from breakers become the only option. At dealers many parts are becoming NLA.

If you can score on eBay, that's nice. If you are going the breaker route, you won't find standard multi-marque breakers yards awash with them anymore... you're 5-10 years too late. To ensure being in a yard with 'exactly' what you require... Wyboston. 25 miles on from Dunstable. Featured on a few TV progs not long back, Barry is a Volvo institution. Some fools ring him to waste his time, asking if he's got blah... he's old skool. He'll be polite about it, but have a way of calling you a fool. As if.... you have to go and look.

Many thanks for replying.
I am tempted to make the journey to see Barry ( Lakes4Volvo) as I need a couple of other bits but I may save time and go the ebay route and hope for the best.
I reckon at best, if I can get a working power stage then I can always play around with the lhd/rhd fitment. Also, I am struggling with the cold days and rain....it's just impossible driving around London with fogged up windows and paying £12.50 (ulez) for the pleasure.
So, can I assume the only difference with the part numbers is fitment?

Many thanks for talking the time to give me some options.
Regards
Andre

'Faulty diagnostic signal from blower fan power stage'

To be clear, in how it's written - which isn't too clear, however they've likely 30 odd chars. max in hthe display.... the diagnostics will be referring to the power-stage of the circuit, ie: as distinct for the 'control-stage' (low current). What will be referred to as the 'power-stage' is the high current section of a circuit. Indicating our fault is in the power-stage of the circuit.

There is no one entity we would name 'A Power-stage', for want of a better parrallel, you might say an ICE has a induction stage, an ignition stage, a combustion-stage, an exhuast stage, and a transmission stage.

In this case, we have a resistor that sits in the power-stage of the circuit, and as the diagnostic states, it's causing a faulty diagnostic signal. Ask your electronics engineer for a power-stage, and he'll ask for a power-stage of what?

With a heat-sink, such that motors won't overheat and cook it, this component is a high-power resistor. I've been wrong before, however I doubt LHD or RHD has much bearing on which resistor Volvo specify in the heater circuit.

CNGBiFuel,
Wow! thanks for taking the time and effort to explain that so clearly. I totally understand now and I also feel somewhat inept. No wonder eveyone was at a loss to what I was on about. There's me going on and on about power stage thinking to myself I've got a dodgy Haynes manual and now I get it....thanks for the lesson.
So control stage (low current) is the socket with 4 wires and the Power stage (high current) is the socket with 2 wires 12v and ground.

Now I am recalling how many different breakers I called up and asked for a blower motor power stage for 1994 850. I am sooooo hoping they knew what I was on about. Blimey!!

I am going to buy one second hand for a lhd (it's all I can get) and hopefully find a way to make it work.

Andre

I'm sorry, somehow I doubt it. I didn't. It was at sight of a power-resistor and 'Faulty diagnostic signal from blower fan power stage'... only then it was clear.

I'm still not sure I see your concern re: sourcing from a LHD variant, unless you know something I don't. Suggest you leap to source say a wheel-bearing and all other obviously non-handed parts from a LHD car, and be very happy.

I think you have this down anyway, however here we go.

Control-stage /low-current stage = The 5V (or lower stuff). Sensors/stats, MAP/ drive-by-wire, control knobs, all the kit that feeds the IC/printed circuitry etc. Inputs into the ECU. Minimal current. Milliiamps. Likely all lumped together on one fuse.

Power-stage / high-current stage = All the grunty stuff at 12V taht would cook ICs/ ECU/chips etc. Motors, rear heated screen, window-motors, anything much over 250mA. This stuff each gets its own 5A - 30A fuse.

Your resistor likely carries 10Amps+. That'll be what the heat-sink is doing. All this stuff is power-stage. Most of it separated by relay from control-stage.. Therein, the function of relays.... separation. These relays, fired by control-stage. Else every switch on your dash would feel like it'd been lifted from a 1960s Land-rover. Operate, more akin to a high-current immersion-heater switch 'clonk'. It's awful, I drive mine most days, the worst car on the road, and I love it - mine requires both feet on the dash to heave the interior-light switch to 'ON'.
Back in the day, a bloke with a Brummie accent said "Hoo nayds an Aye Say U eny why?" and the unions called "Out bruvvers, Out!" at the mere suggestion. This put the Great in Britain, when they went back, it wasn't there.