Wiring setup confirmation needed

[soldave]

Well, after a slight hiccup yesterday at he end of a 180+ mile, 4-hour trip into London, I need to rewire my radiator fans as one of the wires ... well let's just say that it's now smoke and ashes! The setup I have in mind is below, and I was wondering if anyone could take a look, let me know if it looks OK (I'm going to use a fused relay rather than a fuse then relay, but the premise is the same), and then take a look at a couple of questions below. Wires would be 10AWG from battery through relay to fans and then ground, and 16AWG on the switch side.

1. Where would be the best place to get the ignition source from, with the switch part of the centre console in the car?
2. Earths: where would be the best place to connect the earth wire going from the coil of the relay?
3. Earths once again: for the fans, would I be best finding somewhere on the chassis to ground to, or could I run the wires back to the battery to earth?

Thanks in advance. Want to get this right and not repeat yesterday's shenanigans!

Edited July 17, 2019 by soldave

[oilmagnet477]

Hi Dave,

Looks good as is but in order to allow the fans to be left on if the car is turned off hot, could you not just take a separate +ve feed from the battery and switch that and just ignore the ignition?

My Skoda estate often runs electric fans when I turn off the engine (if it is hot) but that will be via a thermo control I guess. Plus, I would run a wire from battery -ve and connect all earths to that near the fans/relay

 

Cheers

Ant

[soldave]

Thanks for that. Yeah,  could easily run a positive feed from the battery, and also run all earths to the battery. I was wondering whether it would be best grounding to the chassis or the battery. So the modified wiring diagram would look like this

[Painterdave]

 My fans were a bit seized up and that was making my wiring get hot so I wol look at them to

[oilmagnet477]

6 hours ago, soldave said:

Thanks for that. Yeah,  could easily run a positive feed from the battery, and also run all earths to the battery. I was wondering whether it would be best grounding to the chassis or the battery. So the modified wiring diagram would look like this

Always one to reduce where possible, take a -ve feed from fan2 to the -ve of the relay and remove the second -ve feed from the battery?

Also, any merit in a 5amp (?) fuse before the manual switch?

[black eclat]

Can you not just wire a switch in parallel across the thermostatic radiator switch?

That would leave you with just 2 wires to run into the cabin to your manual override switch.

[Dunc]

^ This is what I have. Fan runs thermostatically, but I have the option to overide witht he manual switch.

[Escape]

As above, I have similar in my Esprit. I like the ability to be able to turn the fans on manually, but there's always a chance you'd forget, so better leave the thermoswitch in place as a back-up.

Filip

[soldave]

Right, my final plan is trying to make a best of both worlds situation. I'm going to have one fan attached to a new Otter switch which will turn on at 84 degrees or so, and another fan on a manual switch in the cabin. Both will be on separate relays, fuses and wiring so if one stops the other should keep going

[Escape]

I don't really understand why you wont connect both fans to the Otter switch, especially if it's new. I think it's always a good idea to keep the basic functionality, especially with something as important as engine cooling. And then add the manual override, for extra control and redundancy.

Late Esprits have 2 separate relays engaging 3 fans (via 3 fuses). If you want redundancy, you could use the separate relays and fuses as you propose, but wire them in parallel so they both come on with the otter or manual switch.

Filip

[soldave]

Sorry, but would you mind showing me how this would look on a simple wiring diagram? I know I'm very simple-minded(!) but I can't get in my head how it would look running it in parallel.

Once I can visualise it then I can make the decision on whether to wire in both relays or just one.