sorry ,I get the switch light bit now , but the point about operating the manual switch and having a direct short still looks to be a possibility..
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The Road to Morocco (2022)
- Thread starter mikeau
- Start date
One side of the lamp is grounded via the manual or thermostatic switch.
At the same time the relay closes and supplies the other other side of the lamp (and the fan) with 12v.
Are you reading the ground symbol as being a supply rail..?
At the same time the relay closes and supplies the other other side of the lamp (and the fan) with 12v.
Are you reading the ground symbol as being a supply rail..?
Here was what I had in my head Mike..
The manual switch indicator lamp will be on when you operate the switch..as it will get its supply when the switch operates..
You want it on when the fan is running via the thermostatic switch so
You will have to supply terminal 2 in the above diagram with 12 v from the switched side of the relay.. and that terminal will be a direct route to ground for the 12v supply that you want to use to operate the indicator light..
I think you are reading the circuit as if the lower of the two switches goes to earth, but there is no connection to that switch (hence no earth symbol).
The lamp gets 12v to that side whenever the relay is closed and 12v goes to the fan.
The other side of the lamp is earthed either via the switch or the thermostat (either of which also activates the relay) so turns on.
The lamp gets 12v to that side whenever the relay is closed and 12v goes to the fan.
The other side of the lamp is earthed either via the switch or the thermostat (either of which also activates the relay) so turns on.
Looking at your circuit diagram, connect the earth on the lamp to the earth on the fan or earth the lamp at the switch. You have it connected to the 12V supply from the relay.
The bulb is connected to the 12v supply from the relay, and the earth is via the manual or thermostatic switch...
If I disconnect the bulb wire going to the relay 12v output and connect it to earth then the lamp would have earth on both sides and will be very dim!
Have I drawn it weird or something..?
I've coloured in the 12v supply paths to make the observation clearer. I'm happy to concede if my electrical circuit understanding has gone awol over the years.
The relay coil has 12v on the RH side, but requires earth the LH side to operate, which it gets via the manual or thermo switch.
So the LH of the relay coil is earth (chassis), not 12v+
So the LH of the relay coil is earth (chassis), not 12v+
Is this clearer..?
What was I thinking?
Ah, yes of course. Doh!
No worries. Its good that Ive looked at it a few more times and confirmed that its right..!
im still struggling with it lol.... my understanding of the way an indicator light works on a manual switch means that if you supply it from another source that source will go to ground as it will take the easiest path... but thats with the little switches with an indicator light that im familiar with and have used... the indicator light on them has its own ground and takes its supply once the switch is closed...ie it becomes part of the load that is switched.. but as I said you will find out when you wire it up 
... your switch is on the ground side of the coil and not switching a load on the positive side as is usually more normal I think... ie your load is the relay coil which will have a voltage on it even when your switch is open and your switch completes the circuit to ground...
Andy
... your switch is on the ground side of the coil and not switching a load on the positive side as is usually more normal I think... ie your load is the relay coil which will have a voltage on it even when your switch is open and your switch completes the circuit to ground...Andy
Im not that familiar with indicator wiring really, but this is a straightforward relay and simpler, in that it doesnt cycle on-and-off..!im still struggling with it lol.... my understanding of the way an indicator light works on a manual switch means that if you supply it from another source that source will go to ground as it will take the easiest path... but thats with the little switches with an indicator light that im familiar with and have used... the indicator light on them has its own ground and takes its supply once the switch is closed...ie it becomes part of the load that is switched.. but as I said you will find out when you wire it up
Switching the ground makes it easier to run only two wires from the engine bay (where the relay lives) to the dash, it allows me to run one single wire to the thermostatic switch (and take the other side to a convenient chassis point), and its much simpler to illuminate the integral lamp as otherwise I would have to work out how to turn the lamp on when the thermostatic switch closes.
The was the simplest and most elegant way I could think to do it...
Im open to other suggestions...
no other suggestions , and nothing wrong with switching on the ground side.. most stuff controlled by an eco would be ground switched I think...
as I said before, with the switches with an indicator light to let you know its switched on then the issue im seeing is providing a supply to that indicator light when the switch is in the off position... to me that supply will just short as soon as it switches on..
These guys must have overlapped with us (we didnt see them, but its a big country!) and travelled some of the same routes and visited some of the places we were.
Its a nicely put together film;
Its a nicely put together film;
Read this post this morning Mike, epic trip and great account of it. Looks stunning! 
For the time you were away and terrain travelled at least the breakdowns were not too troublesome aside from the wheel coming off early on!! My wife says Iām quite unflappable but I think Iād have sh*t a brick at that point!
For the time you were away and terrain travelled at least the breakdowns were not too troublesome aside from the wheel coming off early on!! My wife says Iām quite unflappable but I think Iād have sh*t a brick at that point!
There must be something wrong with me as Im fairly unflappable... 
Made me chuckle remembering your wheel "moment", a slight slip and correction in the icy snow today and SWMBO had a big old meltdown; imagine if our wheel had come off!There must be something wrong with me as Im fairly unflappable...
