Ls400 Mk 3 Climate Control Unit Blower Switch Problem

[Colin M]

The blower fan switch on my 1997 Mk 3 has just stopped working on the right hand side when pressing it to increase the fan speed, although it works OK on the left hand side when pressing it to decrease the fan speed.

It has been a bit temperamental since I have had the car - it has sometimes needed a few presses to get the fan speed increased but has usually worked eventually, although it now seems to have given up completely. Pressing AUTO has increased the fan speed but the switch itself will not do this.

Is it possible to replace just the fan switch and, if so, how is the switch removed?

If not, how is the climate control unit removed and replaced completely?

Any help gratefully received.

Thanks in anticipation of some help.

[Mybikes a cx500]

A wee squirt of WD40 in the switch might reach the contacts and clean them a bit

[Ruud]

I would be a little careful with WD40 in that area as the circuit board is pretty close to the back of the switch. Maybe try contact spray or a can of compressed air first? :)

[Rupert Dubreaux]

Hi Colin , on the Mk3 the fan control rocker is not actually the the electrical switch ,this is two rubber pads behind the rocker that make contact with the PCB much like a computer keyboard or remote control arrangement . If the plastic rocker part is broken you can replace this on its own ,if as is more likely it is the PCB or the rubber pads that are the problem you could try cleaning them with some isopropyl alcohol or similar . Although Ian's idea is usually a good idea in most cases I don't think it would work hear as the rocker part is someway from the PCB .

In order to try cleaning ,the unit would need removing from the car ,this is a fairly easy job .

http://www.lexls.com/tutorials/audio/headunit.html

Although this shows a Mk1 the procedure is very similar .

If you need the plastic fan rocker part I have a spare one .

Good luck with getting it sorted .

[Mybikes a cx500]

Switch contact spray would be best, yes, but I don't think WD40 would bother the circuit board, and its more likely to be to hand?

[Mybikes a cx500]

I stand corrected, Rupert knows the switch, and sounds like a cleaning job as he says, on the contact pads

[Ruud]

Agreed Ian, but WD40 is quite greasy/oily so a place treated with WD40 is more likely to collect dirt/dust which might give more trouble in the future.......Just my logic :) I could be wrong

[Colin M]

Thanks to all for the advice and suggestions on this.

I decided to start with what I thought was one of the easiest and lowest risk options - a few blasts of compressed air around the switch.

Rather than use my compressor at the outset, I used my foot pump with a cone-shaped piece of plastic inserted in the end (a foot pump accessory normally used, I think, for inflating air beds) to see what effect this would have - a few blasts whilst operating the switch, turned the ignition on and then tried the switch.

It worked fine!!

It increased the fan speed as it should and decreased it when pressed the other way. I tried it several times each way and no problem.

I assume it must have been something like a bit of dust which was preventing a proper contact.

Of course, I may have blown the dust elsewhere and stopped something else from working ... but hopefully not!

Thanks again, all, for you help - much appreciated.