Wiring in a 2nd cold air fan

[stuthemong]

Guys&Gals,

Due to cooking in the cabin, more than a gentle whisper out the vents would be appreciated! I found Luckyone's post in this thread ( http://tinyurl.com/coldair ) and have got the fan he mentions in front of me.

The big question is how to wire it up!

http://www.theminiforum.com/tvr/wiring-diagrams/co...

is the wiring for the cold air box, and from the electrical connections PDF file on the same site you can see that pins 1 and 2 of 'heater cold' are "ignition (green) size 2." and "cold speed (black/white). Size 1.5". I am assuming here that the Fan ECU control box outputs a 0-12V signal on the 'cold speed' wire to create potential between the ingition (12V live) on the cold air fan. Max speed being when cold speed is 0V or grounded.

This is all based on assumption though! I have no idea what those resistors are in the cold air fan box - any ideas?

Does anyone know if this is true? If so, does anyone know if that output from the heater/AC ECU will support another MAX 4A load on that output? If so, I could just wire my inline blower to the same wire in parallel and have nice variable control.

Any help / other suggestions appreciated - I'd like to get some puff!

Edited by stuthemong on Friday 17th July 17:29

[Dan225]

I would have thought that max speed is at 12V, taking current from ignition, and looking at that diagram, the resistors are what varies the fan speed by being in series with the motor. Having never looked at the wiring of a TVR cold blower I could not advise further, but im sure someone will be along to help you soon.

[stuthemong]

I take your point about those resistors acting to reduce fan speed - but then surely the pins 1&2 would be connected to ign via a 3-way - as is they are just left unconnected. It's very weird.

I suspect playing with a voltmeter will confirm/reject my idea of how it works - but that won't answer whether if it does if you can just wire it into the same circuit without overdriving the system / melting wires or fuses?

[BGB autosport]

Check what current the existing motor is pulling at full speed and start up, add the new motor current and see if its still within the fuse rating. If it has the correct fuse in then it should not melt the wires, at worse it will pop the fuse.

[Luckyone]

Hi Stu,

This is where I put my fan (sorry pics are rubbish)





You can just make out the direction of flow arrow on the side there, it's pointing to the transmission tunnel,

Hope you get yours going, when you get the variable speed going I'll copy you