Temp Gauge

[biksz]

bought a temp gauge and when wired up it reads 40c when engine cold when i touch the sendor wire to the inlet manifold it reads 150c and this is while the engine is stone cold and not even run. there is three wires a live an earth and a sendor wire tried on my main car and same thing is there a way of wiring up or is it just faulty.

[ibrooks]

It just suggests that the sender isn't the correct one for the gauge. With the sender wire unplugged (and not connected to anything) what does the gauge show?

 

The sender will have a resistance that varies with temperature (as it gets hotter it's resistance drops). You need to find out what the gauge is expecting as it's obviously not the same as the current sender. It might be possible to tweak the current sender with resistors in series or parallel to get it reading something like correct but I wouldn't bet on it being anything other than a very rough approximation.

 

Iain

[Guest mower man]

Hi most gauges I have seen require a feed to the gauge ,the sender is then fed via the gauge and it is earthed throu varing resitance to give temp reading you need the sender that is matched to the gauge why a sender needs 3 wires I don't understand it sound more like a fan switch. what gauges are you using ? ,keep in touch mick

[biksz]

its an led gauge think might of sorted it as it changed after being left connected so might have reset itself once wired up and it came with the sendor.