RogerH Posted May 13, 2019 Report Share Posted May 13, 2019 Saturday afternoon I pop out to the fuel station to top up for the TSSC New Forest run yesterday. When I got home I noticed that the temp was very high and the fan hadn't come on. No problem I'll just flip the override switch. Sadly it was a problem as that had no effect either. So I gave it one of my looks and lo and behold it started working. Didn;t have much time to play with it so I put it down to a gremlin. On the run I had no problems but I occasionally flips the override and found it was not working. What can possibly go wrong !!!!! The fan could die, but would it recover every now and again. The thermostatic switch in the pump down pipe could could go duff but the override switch would eliminate that. The override switch could go duff but the thermoswitch should eliminate that. Could they both go duff together - ooer!! But the switch made the warning light come on. So, firstly swap out the relay - no joy. Check the continuity of the wiring - what wiring - where is the wiring diagram. OK - after a great deal of messing about I found a wire common to the thermo and override switch that should pull the relay coil in was not behaving it self. I could only get to the ends of the wire as it was hidden in the loom. The ends were fine, so there must be a break internally along its length. Could there be a failed splice in there.!!! It can't be burnt out - 100mA coil with 8 Amp wire - no way. So I now have a working fan (for how long !!!) with a piggy backed repair wire. AND a wiring diagram. I wonder what tomorrow will bring Roger Quote Link to post Share on other sites
MikeF Posted May 13, 2019 Report Share Posted May 13, 2019 HO! Could you come and give my window lifts a serious look please? Alternatively do your looks work over Skype? QUite possibly the break in your wire is at a stress point, ie just inside the insulation near the connector, you could try taking an inch or so off and soldering [in a new length] and connector. Or just wrap your new wire into the loom, that would make a fix into a repair Mike Quote Link to post Share on other sites
RogerH Posted May 14, 2019 Author Report Share Posted May 14, 2019 Hi Mike, sadly my 'look' has no lasting powers. Having replaced what was an open circuit wire with a wire that made it work it has stopped working today. So tomorrow I shall take it apart and see what is going on. I fear it may be the actual fan. Oh Dear Roger Quote Link to post Share on other sites
Z320 Posted May 14, 2019 Report Share Posted May 14, 2019 Allow me to mention I'm very pleased with my BMW 1602 red plastic fan on the crankshaft. Quote Link to post Share on other sites
Tim D. Posted May 15, 2019 Report Share Posted May 15, 2019 Could be an earth issue which would be common in both systems. Quote Link to post Share on other sites
RogerH Posted May 15, 2019 Author Report Share Posted May 15, 2019 Hi Folks, Just come home around the M25 with no fan - thankfully no jams (miracle). With the override switch ON. I waggled the two pin plug/socket coming form the fan - Lo & Behold the fan came on. So it is something to do with the connector (probably) Interestingly the earth return wire, from the thermo switch, has a 39 ohm resistance compared to the Neg post on the battery.!! more investigation to do. Roger Quote Link to post Share on other sites
ChrisR-4A Posted May 15, 2019 Report Share Posted May 15, 2019 Hi Roger, I had a similar problem a few years ago and although my solution does not appear to be the same as yours I will repeat it anyway in case it helps someone else. I cured my problem by removing the Ammeter and cleaning the connections on the back, what was happening was corrosion was causing high resistance and the ammeter could not pass enough current to run fan and overdrive solenoid. Has never been a problem since. Chris Quote Link to post Share on other sites
RogerH Posted May 15, 2019 Author Report Share Posted May 15, 2019 Hi Chris, that is an odd one. How did you find that the ammeter had corroded connections?. Roger Quote Link to post Share on other sites
RogerH Posted May 16, 2019 Author Report Share Posted May 16, 2019 New day fresh brain. It is now all working again !!! I could not find any positive issue. The connector block (push on spades) looked grubby so that was cleaned and a squirt of 'Servisol' cleaner. I don;t understand how the first red wire that I found 'open circuit' was actually OC. But I measured it a number of times. All very odd. I shall run it up on the drive and thermo to switch in and see what happens. Roger Quote Link to post Share on other sites
Andy Moltu Posted May 16, 2019 Report Share Posted May 16, 2019 If the override isn't doing the trick it's unlikely to be the thermostat. SO it's either the 12v feed, the earth or the fan itself. (or the relay if fitted) Quote Link to post Share on other sites
RogerH Posted May 16, 2019 Author Report Share Posted May 16, 2019 Hi Andy, that was the process I was working down. I think I have cracked it now corroded connector feeding the fan (+12v and earth). I'm sure I'll be out there tomorrow fixing it again. Roger Quote Link to post Share on other sites
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