Err, Umm, Wow. Thank God for Greeners.
 

As some of you know from this thread, my fan controls had been bypassed by a previous owner/"mechanic", leaving me with an ugly manual switch in the dash. After taking the bumper off, I could see the control box bypassed, and 4 wires hacked into just before they entered the fan casing. What I couldn't understand was why 2 of these wires were heavy gauge, but the other 2 were more like control signal cables. Well now we have the answer........

Greeners foolishly/bravely/suicidally offered to help me take the whole lot apart this morning, with the hope of sorting this bodge-job out. What we found was, err, different.

As posted in the above thread, the control box was outside of the fan unit, wedged between the fan and the intercooler pipe. So off came the fan today, and what did we see but.......

http://s7.postimg.org/3xbypccsr/2015_07_18_09_58_27.jpg

Yep, not one but 2 control boxes, with the dangly one sort of feeding the other.

Greeners worked his magic, and before you know it we had the arrangement in all its glory laid out in front of us.

http://s15.postimg.org/kur60mw3f/201...8_10_19_31.jpg

So diesel and petrol control boxes, wired together along with a direct live from the cabin switch, and a new earth for good measure.

I'm delighted to say that, having looked at some of David's spares and a few photos, followed by a circuit diagram, we (i.e. Greeners) made the necessary adjustments to remove the petrol box and get the proper 2 wire, 2 speed config in place.

So Guinness World of Records - is this the first Rover 75 to have TWO control boxes? Most importantly, demist test works great, car reassembled and now for some on road testing.

Massive, massive respect to David for his awesome help and quality standards.

Kev

My mind was boggling with only one control box to contend with!
Now all you need to do is find something to wire up to the dash switch :D

Good job both.

That'll be my FBH override. ;)

Well that was a first for me .......


What said mechanic had done, was instead of fitting a diesel fan, had bought a two speed petrol fan, having then worked out it's not plug and play they used the diesel control box to pick up a live, nailed a switch on the dash, and then fed the live into the petrol control box


I must thank spammy (aka Stocktake) for an excellent diagram

A pleasure to do it, and sort another bit of bodgery out

Hi David.
Nice work I presume you have used the two wire 2 speed from the petrol fan, using the fan motor and it's two wires red and black then rewired it incorporating the gold resistor to the original diesel control box, doing some wiring changes in the diesel control box also.

Hopefully you also kept the relays from the petrol control box as they always come in useful.

I would not want to take my car to whomever did that bodge job for any sort of work, again well done cheers Arctic.:}

Steve

Yes basically took the two speed / two wire petrol fan, dumped the petrol control box, and rewired the diesel control box ala Dave's diagram, and away it went .....

Well Kev's popping back to swap the red and slate round as there's an error in the drawing....:duh:

Red and Slate for some reason sometimes need to be exchanged, not sure why. but all that happens if this is the case is the high speed is energised instead of the low.

D...

Dave

TBH, we were so ecstatic that the fan was working on it's own (ie no manual over ride) we assumed it was correct....

Thinking about it, it might be correct.......but need to check or it'll eat the brushes in no time

Plus you get a chance to hear the latest on National's attempts to sort my top mounts David......