Knobs

This post might contain photographs, anyone keeping half an eye on regular posts will know that as far as pictures are concerned I am the apogee of inabilities. However I will try once more.
Why are heater knobs so expensive, even the original Mk1 f examples command silly prices, £50 + for a set of three uninspiring injection mouldings
I was pursuing an idea where I wanted to fit some components behind a knob & being ill prepared to pay an objectionable price I took a punt on £6 worth of repro air con for a ford focus, which when fitted with the steel collar of the originals make a tidy set.

When my knobs cracked at the tube socket, I bound them with multiple layers of heatshink tubing…….. sorted!

Hum, (thinks!) & cheaper than viagra. Thanks Cobber.

Well I s’pose you could reinforce your old fella with heat shrink tubing…..but I can’t imagine that the application of the heat gun would be all that comfortable, mind you I never cease to be amazed by what some people find exciting

In retrospect not only would the application be problematic but the removal at a later point might create some interest. But as you imply it’s whatever inspires you.

Getting back to the thread, boring but I'm intrigued, what were you fitting behind the controls, lights? I ask because I tried using fibre optics but it was a failure (one of many). The fan speed control also appears to have an extra hole/light on it's face is this a mod or standard?

Ah, observant, there's a three position switch & an LED. With the roof up & on cold mornings my car mists up, much in the same way as every other f & ft I've had experience of. I reasoned that passing more air across the screen would shift the mist quicker & save me struggling against a locked up seat belt whilst trying to wipe sufficient area to give me a clue where I was going.
I set up a test rig in the workshop using a similar fan & ran it on 18v for a day with no apparent detriment. You can buy power units of eBay for a few quid that will jack 12v up to 36v if you wish, I stuck with 18 & that accounts for switch position one.
Position two is off & three is continuously variable. I removed the switch & resistor network & replaced it with a pulse width modulation control that gives me any fan speed I choose. So yes behind the knob there's a small board, which acts as a terminal for the "clock" Spring I wound to allow free movement of the controls which sit snugly behind the knob & the LED its current limiting resistor plus the switch.
It hasn't been used in earnest as yet but has proven reliable on "dry" test runs.
I have a picture of the arrangement but it's on another device whose whereabouts is unclear at the moment, I'm not very accomplished at keeping track of my various computers, with the exception of the one in the workshop, which has remained rooted to its spot since I moved a tool chest in front of it.
When it crops up I'll try & post it, try being the operative word.

That didn’t take long to find, my ever efficient darling wife of 45years put it next to the kettle, a place I return to regularly. My photographs aren’t normally for general consumption as they can be masterpieces of over exposure & out of focus, these two however have bubbled to the top of a poor batch.

I agree the fan on cold mornings is inadequate and if your motor holds up which in my very limited experience it probably will then I think its very worthwhile modification. Perhaps after successfully testing it for a while you could share the details of the PCB for others to follow, my only concern is the tiny 3 position switch. I'm not sure my old fingers on a chilly morning could identify the 3 different positions and personally would probably fit a 3 position rocker switch.
Sadly I'm unlikely to follow you having just discovered this week that I can't seem to be able to solder 2 wires together! it appears since dad taught me using a big copper tipped iron on the gas ring over 50 years ago things have changed. After much googling I now have on order ROSIN coated lead (naughty) solder and hope this will resolve the issue.

Providing all the kit is working correctly, in one position the motor will be going crackers, if there’s no sound then the switch is in the off position (or something buggered up) & in the third position everything is normal, or what passes for normal in our cars. You need only to twiddle with the switch to derive the appropriate noise & your good.
Getting electronic devices in to deceptively small spaces is a specialty of mine, I’m fitting the steering wheel mounted radio controls from a Rover 25 to my car at the moment & because I want to utilise couple of spare ways in the wheel clock spring, I need to mount a circuit board in the wheel itself without interfering with the airbag etc & then interface it all with the radio, which is a Sony.
And no it’s not a straight forward job, not for the faint of heart unless you use all the Rover kit, wheel, cables & radio.

Well impressed with your enterprise!:clap: