electric fan capillary thermostat 12V source

[steve_k]

evening folks.

looking for info/advise,

i'm looking at installing an electric fan on the front of my e30's radiator.
i'm going down the adjustable capillary thermostat route,

one of these \/\/\/\/\/\/\/\/

https://www.ebay.co.uk/itm/Adjustable-e ... ctupt=true

now, got the fan in place, got the controller in place, ground wire all set up.
just trying to find where the best place to get a switched 12V from??

looked online & some say the washer bottle pump (yet no mention of what colour wire to tap into) other say the big block on the bulk head on the drivers side.

so, which would be the best to use? i want to keep the wiring as clean/simple as possible.

[Brianmoooore]

Best place would be the green/black wire of off fuse 19, which is what BMW intended for the purpose, but the purple/black on the washer pump would be an acceptable alternative, as long as you consider that this is fused at 30A rather than the 7.5A of fuse 19, and size your wires accordingly.
"Big block on the driver's side" doesn't exist on any UK vehicle I've ever seen, and isn't fused on any vehicle that does have it.
Why are you going for a capillary switch, instead of the correct type, part way down the radiator. A capillary switch isn't in the ideal position to switch a fan, and will run the fan before and on other occasions when it's not needed.

[steve_k]

Best place would be the green/black wire of off fuse 19, which is what BMW intended for the purpose, but the purple/black on the washer pump would be an acceptable alternative, as long as you consider that this is fused at 30A rather than the 7.5A of fuse 19, and size your wires accordingly.
"Big block on the driver's side" doesn't exist on any UK vehicle I've ever seen, and isn't fused on any vehicle that does have it.
Why are you going for a capillary switch, instead of the correct type, part way down the radiator. A capillary switch isn't in the ideal position to switch a fan, and will run the fan before and on other occasions when it's not needed.

thanks that Brian,

i don't fancy splitting the fuse box open to be honest, also my reason for using the capillary (while not ideal) is mainly down to cost, as i already had one in stock & they appear to be the "easy" option. also i will be able to "set" the temp at with it switches the fan on depending on use.

as for the purple/black wire, i have already got an inline fuse ready to use complete with a 30A fuse & the wire i'll be using is more than capable of being used there (asked an auto leccy mate for the correct rated wire).

just want to keep it all nice, simple & clean looking.

[Brianmoooore]

If you dig the (probably) unused socket for an interior light delay module out from its hiding place next to the locking ECU, you will find a green/white wire attached to it which also comes from fuse 19. This wire can be cut free, partly rerouted and then extended for your purposes.
Your 30A inline fuse is presumably for the fan motor, not its control circuit, and should be connected directly to the battery + terminal, or the large terminal of the bulkhead 'phantom' battery block, if you have a rear mounted battery.
An electric fan should not be used to control engine temperature in any way, other than to prevent overheating. The engine running temperature is set exclusively by the mechanical thermostat in the coolant outlet elbow, and all any fan should do is to cool the water in the radiator when there is insufficient air flow through the radiator as a result of the car moving. If the car overheats when the car is moving at any speed, then either a larger radiator is needed, or, in most cases, a new one.