In December we had yet again another reappearance of the cooling fans not kicking in at low speed. I again fitted a new new relay which didn't fix the issue. By now I had a good collection of relays (2 new, the original and the X300 one fitted 3 years ago) and refusing to believe that all were faulty, did some diagnostic digging over the Christmas break.
So out with the electrical circuit diagram and a magnifying glass.
- First checked the fuses which looked good, but changed them just in case. No change.
- Next checked the operation of the radiator thermo switch with a multimeter (earth pin beside the LH air box and positive on the relay plug base and monitoring the temp using an IR thermometer on the top radiator hose. The low temp switch in the sensor closed bang on @86 deg.
- Checked the fan operation by carefully stripping the cover off the original relay, plugging it in and manually activating each relay. Both fans worked in low and high speed.
- Using this relay I then hooked up a 12v battery and checked the relay operation. All clicked as they should and then checked one of the new relays which also clicked away.
- By now I was thinking dirty connectors or a voltage drop and so proceeded to clean what connectors I could easily get to and the earth point with no success.
On a more positive note Lady P now has new shoes!
The Bridgestones she was wearing still had a good depth of tread, were evenly worn and had no cracking, but decoding the date stamp in the sidewalls revealed they were over 15 years old! I ended up fitting a set of Michelin Sport Pilot 3 tyres in the original 225/55R16 size.
The change in ride and handling was immediately apparent. The ride is noticeably more compliant, steering a bit lighter and I can get an extra 20kph going round my fast test corner near home. I could have gone faster but the pucker factor kicked in and it was double demerits season here. Previously I would be feeling the old tyres starting to loose grip and squealing at far lower speed.