Switching two fans on one aux

[SteveX]

Hi Gents,

I've got a spare fan that was fitted on my old charge cooler rad (that appears to have not even really been wired in right) so I figured I may as well fit it to my new rad seeing as it's going spare and wire it in properly.

I wasn't going to bother originally as I didn't want to block flow (it was fitted as a push style fan) but the part number shows it's a davies craig fan that's fairly decent and can be reversed, so I spun the blades around and will reverse the polarity that way it shouldn't block flow but make a nice pull fan. The previous person who fitted it just piggy backed the fan off of the rad fan on the old charge cooler > pretty useless tbh. It was originally hooked up to the ECU though, as I see what appears to be a fan control on Aux 5, traced the wire, it does go into the loom and off somewhere but I am 99% sure it was originally the charge cooler fan and when the kit was fitted to this car the loom was broken on that wire and not used.

Anyhow, my car originally also had an engine lid fan which was pulled out by the engine builder for some reason, I might get another one and stick it on the lid. I've got some standard 30A 4 pin Bosch relays. Just thinking of heat soak sat in traffic in summer.

I'm thinking of using the ground part of the switch circuit on aux 5, but I wanted to know if it was fine to piggyback two grounds to that one aux (since I'll trigger both off of a combination of ECT and IAT). Just planning to pull the same 12v ignition feed to each switch side of the relay's them combine them to the one ground on switch to the relay from the the Aux.

It sounds OK to me, there will hardly be any current, I believe the link can take 3A, so no problem for just a feed with nothing drawing on the switch circuit, but figured best to check here if people have switch two relays on one Aux fine before.

 

Thanks,

 

Steve

 

[Simon]

To relays of the one drive is 100% acceptable. Only requirement is that the current draw is under 2 amps 

[SteveX]

Thanks for the reply, if I go ahead with it i’ll combine the two switch grounds to one 2a fused wire going into the aux output just to make it safe in case of any surge.

Cheers.