Power Stage fix

For all who doesn't succeeded with all the very good hints written in the internet, here my solution.

I have a 850-T5 94 with automatic clima control. Nowadays I use this old vehicle only two or tree times a year for long trips.

One morning now after a trip my blower run only for 10 or 20 seconds. Then silence. Code 411 417 418 419

I checked the internet for solutions. I checked all the error codes. Unfortunately no success.

Then I checked the blower motor….. result good

Then I threw my interest on the power stage……. Difficult to say OK because all looks good.

My old Sanyo Mosfet behave as is. I tried even other new ones but now better result.

Now before ordering a new Power Stage, I unsolder the capacitors and the varistor. And one capaciter looks a little brown on bottom. I replaced this original 10uF 25V with a 10uF 50V and all others with the value printed on it. As well I changed the varistor with a new one. Cost of material less than 10 CHF.

And the following test in the Volvo was fine. Wow I solved my problem. The blower fan blows as new and the whole clima control works again absolutely fine.