Erratic demister behaviour
 

Since I've had my S40 (2002 phase 2) there's been an issue with the demister/blowers whereby on certain settings (that have no pattern, sometimes when on 3, sometimes when on 5 and so on) whereby it will blow as normal, then suddenly really fast, then barely at all, fast again, and so on. Moving the dial to another number usually stops the problem but it reoccurs on different settings on occasion.

Is it worth pursuing or should I just put up with it?

Thanks in advance

Its a common fault in our car. The potentiometer inside the heater control panel that controls the speed wears out over the years. If you know how to solder then you can try to fix it yourself. See here: https://www.volvoforums.org.uk/showt...l+panel+repair

If you can't solder, then you can either look for a refurnished heater control panel on ebay, or you can send it over and I can do the repair

Thanks for your reply!

I'll have a look at work later if it's quiet, may be able to solder it myself, it's something I do but not very often.

I'll report back with my findings...

Managed to get time to strip it down this evening, is it literally just a case of removing the old potentiometer and soldering that new one in? If that's the case I'll have a stab at doing it myself first, got nothing to lose - I notice the middle of the three is sandwiched by another small PCB so would like to avoid changing that one!

Wonder how much Volvo would charge to rectify this :shocked:

You only need to replace the one that is responsible for the fan speed. No need to replace the middle one, as it hardly ever fails.

As for Volvo, they wouldn't touch it. They would happily sell you a brand new heater control panel for a small fortune.

Thanks very much for your assistance, I shall order a new potentiometer and get back here with results when I've finished it - particularly in light of some recent posts where people vanish after getting answers about a fix!

It's certainly worth looking at doing the work yourself or taking up the offer from Gatos.

I've done similar on the CEL unit to replace relays that had caused one headlight to stop working.

The component parts are very inexpensive and at least you know how to do it in case the same happens again on this or another car.

Hi Gatos, I clicked on the link as I was interested to see the suggestions ... & realised it was what I'd posted! LOL

Glad it's been helpful to people on here.

So it turns out after some practice on other bits, I'm not great at soldering!

Gatos, I will take up your offer, I shall be in touch by PM.