JMC 0 Posted July 30, 2008 Just had a fuuny day with my G60. Driving along earlier and the fan came on in traffic (as per usual) then didn't want to go off again, even when everything should be nice and cool (70mph, free flowing on the mway). Parked up, and that fan was still running (not a big shock as it had been in stationary traffic for a while just before parking). Locked up and left, came back 3 hours later and the battery was dead. Jump start, drove home, and the fan again came on in traffic, and didn't want to go off again. I've done the following tests... Ignition off, engine relatively cold, disconnect connection to thermoswitch on the block and earth it. Fan comes on. Take the earth away fan goes off. As it should, so it doesn't seem to be the thermoswitch. Took it out for a spin, got it just up to temp of the fan coming on. Fan came on. Straight away switched off the engine and left it for 15mins. Fan continued arunning nd showed no signs of switching off (also tried disconnecting the thermoswitch at this point and the fan continued even when that was disconnected). Then, unplugged the fan (obviously the fan went off), and reconnected straight away, and the fan remained off. :shrug: Really confused by this, as I initially suspected the thermoswitch, but that seems to be working alright. What happens when the big black fan control box fails - is it this type of thing it does, and if so how best to check it? Any advice would be great please folks. Quote Share this post Link to post Share on other sites
2_Door_fun 0 Posted July 30, 2008 HI. Another G60 fan problem.... belive me the forum is full of em.. I have just removed my stock item as it will just not come on..Works fine when Earthed and works fine with a manual switch on the dash..So deduced that it could be a an actual fan problem..I changed to a Spal fan and still the problem perists :shrug: Again it works fine with the manual switch.. My run on for cooling under bonnet temps after ignition is turned off does not work either.. The run on circuit is linked via a Relay but from my knowledge this does not interact with the actual rad fan operation. The running operation is controlled via nothing more than voltage and the rad mounted thermo switch.... What or where is the big black module you speak of ! later C's had Relays or a control unit mounted up by the radiator resevoir..Early G60's do not have these relays.. All I could suggest is that the actual small loom the connects the rad and switch to the power supply is weak and a new one is needed.. This ill be my next purchase... let us know if you get any where with it. Cheers Rob Quote Share this post Link to post Share on other sites
JMC 0 Posted July 30, 2008 Cheers Rob. The big black box is the one near the coolant reservoir that you mention (mines a 92 G60). One thing I haven't tried yet is unplugging the rad temp switch when it is running to see whether that is what is cauing it (maybe it is not switching off as early as it should). Will try that next time it is up to temp. Quote Share this post Link to post Share on other sites
MattWilde 10 Posted July 31, 2008 this is probably wrong but it might help. Have you tested the screw in sensor on the fuel rail that makes the fan run on after the ignition is swtiched off? or any relays/wires and associated stuff with that sensor. Quote Share this post Link to post Share on other sites
dirtytorque 0 Posted July 31, 2008 I had similar prob. fan run on after engie cut off till batttery dead.It got to the stage where I couldn't make any journey where I had to stop b4 returing home as the battery would be dead. changed duff low temp rad switch and fan control unit.(I have a late g60). Quote Share this post Link to post Share on other sites
JMC 0 Posted August 1, 2008 Hmmm, the plot thickens. I tried disconnecting the black fan run on control box in the engine bay, and that had absolutely no effect what so ever (fan still didn't go off). The high temp run on switch next to the fuel rail works as it should too. Basically the fan comes on at about 80 (I have a low temp fan switch), but then doesn't go off again even when the car has got back down to 70 (I have a low temp stat as well). So once, it's on it doesn't go off while the car is running. Then when parked up it seems as though it ran until the battery went dead (it was a very hot day, parked in the sun, after a long run through traffic). So I've swapped the rad temp switch for an old one I had laying around, and guess what, comes on, and goes off when it should. Looks as though it was the low temp rad switch that was the problem. Going to test it tomorrow to see what temps it actually switches on and off at. Quote Share this post Link to post Share on other sites
dirtytorque 0 Posted August 1, 2008 Same as mine then.I'm just running a normal temp switch now although I have a low temp stat. That thing caused me loads of grief. At least you spotted it early. :thumbleft: Quote Share this post Link to post Share on other sites
JMC 0 Posted August 1, 2008 Yeah, I think I might do that from now on. Atleast then I shouldn't have too many problems with the fan staying on after I park up, as the steady state should be 70 degrees. Quote Share this post Link to post Share on other sites
