Twin fan setup wiring. brian? ;)

[gareth]

this weekend i'm planning on getting the twin fan setup wired up so i don't kill the M30

i have the following parts:
1x citroen BX 16V twin fan seup (both fans wired independantly)
2x E32 dual stage fan switches (80Ԛ°C and 90Ԛ°C points iirc)
2x 40AMP quality tyco automotive relays
1x low fan speed resistor (unknown value, from the E32 aircon fan)

i'm thinking the best bet is to wire both fans in parallel with the 80Ԛ°C part of the switch energising the first relay and powering te fans via the resistor for a slow start, low speed, quiet setting. then the 90Ԛ°C part energising the second parallel relay, bypassing the resistor and running the fans at full chat.

does this sound sensible?

also, where should i run the power from? i'm going to run the high load wiring directly from the battery but i'd like to power the dual stage switch / coils on the relays from the fusebox somewhere to get a switched (disables with the ignition) feed. (my 205 gti fan used to bite me when the heat soak restarted the fan with the ignition off so i don't want it to run with no ignition!)

is there a spare fuse and wiring that i can pinch or is it just a case of adding to an existing circuit?

[kam-325i]

I would of thought, that in a twin fan setup, 1 fan runs under normal running and that the second fan cuts in under heavy loads.

[Brianmoooore]

There are two spare fuse and two spare relay positions in the E30 fusebox intended to be used for the aircon fan. Just add some wires.

[gareth]

cheers brian, i'll open the fusebox up and have a play tomorrow.

kam, most manufacturers use the fans on a lower speed first as on full seed they sound like a WW2 fighter plane!

[Brianmoooore]

on full seed they sound like a WW2 figter plane!

I'll confirm that. When I first fired up the fan on my M50 conversion, I thought it was going to start pulling the car along.

[evodan]

Interesting one, I to will be messing around with fans at some point, at this point I've sourced a twin fan set up also, so any pics of the fuse box, wiring and relays set up would be cool Gareth

[Brianmoooore]

Interesting one, I to will be messing around with fans at some point, at this point I've sourced a twin fan set up also, so any pics of the fuse box, wiring and relays set up would be cool Gareth

Nothing much to photograph. An E30 fusebox is an E30 fusebox, and we've all got one under the bonnet of our cars.
Relay positions are K1 and K6, fuse positions are 3 and 18 (first ones low temp, second high).
The relay bases are already powered from the fusebox, and connected to the fuseholders, so it's just a matter of obtaining and fitting the missing pins for the relays and fuses, and wiring them to the themoswitch and fan. There is a blanked off grommet on the side of the fusebox facing the wing to bring the new loom through.

[gareth]