[TR] Lucas Heater Switch

Randall TR3driver at ca.rr.com
Sat Nov 25 15:59:19 MST 2017


> So, I went to eBay and found heater rheostat switches for the Triumpoh as
> either Lucas
> P/N 78384 or 78405. Does anyone know: Are these essentially the same item?
> Will either
> one work on a TR3 heater?

As usual, depends on your definition of "work".

Stock TR3A is either 78262 or 78362 for (probably) post-60k.  They take
different knobs.  78362 is 2.5 ohms.

78384 is 5 ohms (per Lucas 400e master catalog),
78405 is 15 ohms according to
https://www.autoelectricsupplies.co.uk/product/815/category/153

The higher resistance means you'll get less airflow (likely none at all for
the 15 ohm version) for any setting other than 'max'.  But either of them
should give you "high" and "off", which are the only two setting I ever
found to be useful.

Neither appears to accept either of the stock TR3 knobs.

(I didn't check if they will fit in the same hole.)

-- Randall 



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