Morris Minor Owners Club

Hi

I have a A+ engine in my van.
It has a temperature sender on the head next to the thermostat connected to one of the warning lights in the speedo.
My challenge is that this should be a switch - on or off. As it is a sender, it has a variable resistance and the yellow light glows with different intensity based on the temperature - almost like a poor man's temperature gauge! I don't worry about it, but when the kids or missus drive the van they worry the engine is over heating. So a couple of questions:
1. Where can I get a temperature switch (on or off, open circuit or closed) - I cannot find one from the usual susects?
2. Would a resistor in series work to stop the low level glow at normal temperatures - any idea what value?
3. Should I just fit a temperature gauge?

Regards
David

Just fit a electrical temperature gauge using the original style transmitter/sender in the head.
Plenty of kits on 'e' bay to choose from.
The original 'A' Plus engine with 940 head had a transmitter in the head & was connected to a electrical temperature gauge located in the dash - it should not be connected to a warning light.

At worst disconnect the light from the transmitter.

The lamp, in series with the transducer is basically acting as a potential divider. If that lamp were to be replaced by a suitable resistor (or simply put out of site) a signal to trigger a separate warning light could be used for an alternative warning light. A Darlington Pair is commonly used for this application.

I personally don’t like ‘idiot switches’ on their own as they give no indication until the engine is too hot - and even then, no indication if the temperature is still rising.

I knew a pair from Darlington, lovely couple they were too !

Sounds like a previous owner's idea of a 'good idea'. I'd take Phil's advice, either disconnect it or fit a gauge.
A lamp that suddenly switches on is really going to freak the family out.
I'd put the process of finding a switch, of the appropriate thread size, in the 'too difficult to waste time over' category.