Misting Gauges - Solved.

[Hector2021]

Like many i have been plagued by the three auxiliary gauges misting up on cooler days. Mine have been that bad they are almost unreadable when at their worst. Its an S2 so has the back lights illuminated with the ignition on, apparently an attempt by Lotus to remedy this well documented misting problem.
My idea to resolve it was to make a system similar to the main heater fan which can direct warm air to the inside of the windscreen to cure the same problem. I figured a small fan that could blow air into each gauge would be just whats needed.
I bought a 40mm x 40mm computer fan from ebay for £4 and fitted it into an almost exact same size plastic box donated from my partners crafting supplies. I drilled three holes into it in which i could then insert three short lengths of very flexible silicon tubing (ebay £3). The holes were drilled to allow a firm interference fit with no need for any further glueing.
I then drilled a hole the same diameter in each of the three gauges and press fitted one of the tubes into each gauge. As i didnt want the fan to run permanently i intended to add in a switch to operate the fan only when needed, and allow it to be turned off when not required.
Using the blank AC switch i fitted a new old stock Carlton rear fog light switch, also bought off ebay (for £15). All the wiring was already there to the back of the AC female connector (ignition supply, earth, switch lamp) except the feed required to run up to the fan, which i ran as a separate wire. I just made up some crimped short wire straps to join the female connector to the back of the new switch.
It was really quite straight forward and low risk as i figured that if it didnt work i could just tape over the holes i drilled in the gauges to stop ingress of any crawling insects and the whole experience would only have cost me about £25 anyway.
The last touch was to add a filter to the fan box to stop it sucking any dust into the gauges. This was effected by the use of a Typhoo tea bag (unused and emptied of tea obviously).
The only thing left to do was to test it in normal misting up circumstances, which were not difficult to find. I let the dials mist up as usual and then switched the fan on. In probably less than a minute all dials were totally mist free where previously they would have remained fogged up for maybe an hour or so.
I think one of the biggest supporting reasons for its success is that where the fan now lives is inside the dash and just above the heater matrix and main blower assembly. This allows warm air to collect inside the dash which the fan then forces into the dials. It works better and quicker than i expected and i'm happy to report that i now no longer need to suffer the frustration of fogging dials right from the start of a cold morning run.

[dapinky]

This is the sort of ingenuity that I love to see! - I just know I'm going to want to do something very similar, even though I don't really get much of a misting problem.....

.... however, I have some thoughts....

What happens to the water (vapour/droplets/river) inside the gauges? - did you make another hole somewhere for the damp air to escape or is the housing sufficiently ventilated anyway? Same consideration for the airflow really - does it just basically pump-up the pressure inside the gauge, or does it flow freely?

My thoughts are along the lines of to drill another hole at the bottom of the gauge housing to allow a freer flow of air through it and to allow the water to escape at the bottom....... and maybe fit a timer circuit using the same time unit that I use for the fan override.....hmmm, maybe I can even get it to trigger from the ignition, so when I turn on the car, the fan blows for whatever time it is set for and then turn off...... I can see hours of fiddling for this one just to solve a problem which barely exists!!!

[Hector2021]

.... however, I have some thoughts....

What happens to the water (vapour/droplets/river) inside the gauges? - did you make another hole somewhere for the damp air to escape or is the housing sufficiently ventilated anyway? Same consideration for the airflow really - does it just basically pump-up the pressure inside the gauge, or does it flow freely?

To be fair i had the same thoughts too and i did consider drilling another smaller hole to allow air/vapour to escape but given its tiny size, the output from the fan is really quite feeble once its split three ways and doesn't offer much more than a gentle puff of air from each pipe. My current thought is that the bayonet fitting of the illumination lamp is suitably non air tight and will allow a small escape route for any air inside a gauge and equally im hopeful that any vapour may also follow the same route. Also im hoping that the warm air blown in coupled with the heat from the lamp will aid any moisture drying out?
I have only really tried it on three drives so far so it might be a case of seeing if the misting appears worse on initial cold morning start up due to moisture accumulating internally. If so i'll revisit with a better exhaust route.

[Tuga2112]

i absolutely love this solution. and im likely going to copy it..

HOWEVER
i shall be triggering the fan from the de-mist button for the mirrors in the middle of the centre console. its already timed and they will mist under similar circunstances anyway.

that way you can keep the switch for the most important feature your missing.. a period accurate USB phone charger plug

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