Well it's been a while since I first looked into this issue so I thought I would give you all an update. Just a little brief background to the story, since picking up luigi in February 2013 the first stage (slow speed) fan setting has never worked. It has only ever been able to use the high speed which cuts in at around 100 degrees. The reason for this was a snapped earth wire on the fan speed resistor located on the bottom corner of the fan housing which many BIS owners have experienced over the years. For reasons best known to themselfs the previous owner decided not to repair or replace the resistor but to let the engine use the hotter temp setting and to hardwire in a fan switch to manually switch the fan on from inside the car. I firmly believe that this is why I ate so many head gaskets in the first two years. I ended up using waterless coolant because I was at a loose end. My fast idle solenoid was'nt working either so when the fan did cut in the engine shudder which meant that I had to adjust the revs to a higher setting to over come this. Using waterless coolant meant that the high temp setting wasn't much of an issue anymore but it was a hot summer this year and I would've preferred both speeds to work.
This year I decided enough was enough and I was going to sort it and get it how it should be so over the last three days I've been hard at it and today after 5 years I have TWO fan speeds AND a fully working fast idle solaniod....... The joy I'm feeling right now can hardly be expressed in words
In short I had three problems to overcome. The 1st was what happened to that black earth wire that goes on the resistor. I had the two grey ones that go on the other side (see post 4) which the owner had attached to a relay near the radiator. Because electrickery isn't my strong point I had initally thought this was some sort of resistor substitute that the last owner had wired in but it turns out that it was just a relay to work the fan from inside the car. Inspecting the wiring diagram revealed that the fan would come on regardless of the black earth wire snapping off but would only come on the higher hotter setting. So I peeled back the copious amounts of electoral tape the previous owner had wrapped around the two grey wires and hey presto - the black earth wire. So I crimped a new spade on the end and fitted it up and problem number two appears....... It still didn't come on! DOH!
I studied the wiring diagram and called it a night. The next day I pulled up the carpet. The diagram said that the earth ran though a conector block and using a test light I found it. The conector block was corroded to hell (the leaky window screen was the culprit long since sorted) so, I had a new conector block and fitted it in, time for test number 2 and success! The fan cut in at its slow speed halfway up the temp gauge just as it should and never has before in my ownership! I was so happy BUT problem number 3 came. The fast idle solaniod didn't cut in DOH!
The reason the fast idle solenoid didn't work before was because the little lever had fallen off the carb. A good secondhand carb was sourced (complete with little lever) and sorted this out but was redundant as the slow speed fan never cut in but it did work and has always been working until now. More head scratching and another night called in. Next day I studied the wiring diagram (I now know it of by heart) and managed to find out where all the wires went and even got the solenoid to work by hard wiring it to a live. In the end i traced it back to the fuse......it had blown! But why? ...... 2 fuses later and still no joy until I had the idea that my fan, which is an aftermarket one may be drawing more current than the standard one so I fitted a 30 amp one and bingo! A fan that cuts in when it should AND a working fast idle solenoid! I couldn't be happier! Never give up guys!
