Graeme Robinson Posted April 14, 2018 Report Share Posted April 14, 2018 Apologies if this has been addressed in previous posts but can anyone tell me if the panel light switch changed from a push/pull to a rheostat and if so when. I have a 1961 3a (post 6000) and understood that I should be fitting a rheostat switch but the dash itself doesn't have a hole big enough; in fact, I have 2 other spare dashes with the same size of hole. The other issue is that the bezel sold with the new aftermarket rheostat is totally different to the original in that it is very thin and of a smaller diameter. I spoke to TR Trader yesterday to try and source an original second hand switch and their view was that the switch was a push/pull throughout production. Many thanks Graeme Quote Link to post Share on other sites
Ian Vincent Posted April 14, 2018 Report Share Posted April 14, 2018 My 1959 TR3a has a rheostat. Rgds Ian Quote Link to post Share on other sites
RobH Posted April 14, 2018 Report Share Posted April 14, 2018 Yep - rheostat. The mounting hole looks to be the same size as for a standard switch. Item 35 here: https://www.moss-europe.co.uk/shop-by-model/triumph/tr2-4a/electrical-system/gauges-instruments/instruments-cables-dash-switches-tr2-3a.html Quote Link to post Share on other sites
Graeme Robinson Posted April 14, 2018 Author Report Share Posted April 14, 2018 Interestingly I've just been doing some further reading in Bill Piggotts book "Original Triumph TR2/3/3a" in which he states: a) "Most TR2's, TR3's and early TR3a's had the panel light switch in the centre with the wiper switch at the top, however, when a rheostat dimming panel switch became available at approximately TS4300, the positions were reversed because there would be insufficient room behind the dash for the mechanism of the rheostat mechanism if the switch had still been fitted in the centre" "The rheostat only appeared on UK market cars post TS-60001 but it was available on US market cars from February 1959" I assume that when Bill states that the switch was "available" this means the rheostat was an option on UK cars from 4300 and became standard fitting from TS6000 and as such,there is no standard arrangement? Even if this is the case it still doesn't explain why my car (being posit 60001) doesn't have a hole big enough unless it was still only an option? My other query is that there appears to be more room in the centre of the panel than with the top position owing to the ignition and indicator warning lights. Quote Link to post Share on other sites
RobH Posted April 14, 2018 Report Share Posted April 14, 2018 (edited) The rheostat on my car is in the centre position. Unfortunately without taking it out I can't check the hole size properly but from the visible thread it looks to be 1/2 inch diameter. The bezel (nut) on mine is different from the wiper and light switches so possibly its not original. Edited April 14, 2018 by RobH Quote Link to post Share on other sites
Fireman049 Posted April 14, 2018 Report Share Posted April 14, 2018 (edited) My 1960 3A (post 60,001) is fitted with a rheostat panel light switch at the top of the panel. Tom. Edited April 14, 2018 by Fireman049 Quote Link to post Share on other sites
Kiwifrog Posted April 14, 2018 Report Share Posted April 14, 2018 My 3A ex USA has the standard pull/twist, date of manufacture was wednesday 6 July 1960. the car sat in a garage from 1971 till I restored it a few years ago, very rusty as it was a NY car but very origonal. I guess its what they had to hand in the factory when the car rolled down the line or the rheostat was still an option at that date cheers Alan Quote Link to post Share on other sites
james christie Posted April 14, 2018 Report Share Posted April 14, 2018 My 3A is a November 1959 product - post 61000 - and has a a rheostat. Like most it has never worked except off/on James Quote Link to post Share on other sites
Fireman049 Posted April 14, 2018 Report Share Posted April 14, 2018 If you fit LED dial illuminating bulbs then the rheostat switch won't dim them. Then why fit high illumination bulbs and then want to dim them??> Tom. Quote Link to post Share on other sites
Lebro Posted April 14, 2018 Report Share Posted April 14, 2018 (edited) Well, I did because the original lights were too dim, & the replacement LED's too bright. you can dim them, just not with the standard rheostat. I used a smaller wirewound "potentiometer" rated at 5W, & with the spindle machined to take the standard knob circuit below: Bob. Edited April 14, 2018 by Lebro Quote Link to post Share on other sites
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