Hi down near Seville, just stopped for the day. 1998 ducato 2.8 idtd, radiator fan won't stop, engine has had a chance to cool down Guage showing lowish temp but won't stop, I have disconnected the battery and the fan relay box is still clicking away, any advice appreciated.
Technical Radiator fan wont stop
- Thread starter mcubbin
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Technical Radiator fan wont stop
Communicator
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Hi,
Thanks for posting the resolution. I was just typing a reply which I have deleted.
The fact that the relays were still operating with the battery negative disconnected suggests that you may have a faulty earth connection. The power for to make the relays click must have come from somewhere, and as I presume that the vehicle is a motorhome that can only be from the habitation battery. If you have a faulty earth connection shared by the fan thermostat, and somthing connected to the habitation battery, then it is possible for current to ground via the fan relays, and something else controlled by the ignition switch. Given the age of the vehicle this seems quite possible. May be difficult, but if possible trace and check the earth connection for the thermostat.
Thanks for posting the resolution. I was just typing a reply which I have deleted.
The fact that the relays were still operating with the battery negative disconnected suggests that you may have a faulty earth connection. The power for to make the relays click must have come from somewhere, and as I presume that the vehicle is a motorhome that can only be from the habitation battery. If you have a faulty earth connection shared by the fan thermostat, and somthing connected to the habitation battery, then it is possible for current to ground via the fan relays, and something else controlled by the ignition switch. Given the age of the vehicle this seems quite possible. May be difficult, but if possible trace and check the earth connection for the thermostat.
To add to Communicators post, if you have solar panels, then even if you disconnect the main and habitat battteries, there is a possibility (in sunlight) that there is enough power from the panels to semi power some accessories.
Have this on my van and have to disconnect the panels if working on the electrics.
Have this on my van and have to disconnect the panels if working on the electrics.
. 
Just done another 100 miles and all seems OK. But interested in where the relays were getting the power also, I am not bad with electrics if starting from scratch but not so diagnosing faults. A few more details, first I only disconnected the earth cable from the starter battery, I do have 400 watts of solar going to 2x110
A/h leisure batteries, it was dusk at the time not much coming from the solar but I was on electric hook up with a 25a ctek charger connected directly to the leisure batteries. It is a hymer so there is also an ebl charging both sets of batteries, the ebl is not good enough to charge 220 a/h on its own, there is also a cable going from the solar controller to the starter battery for a 1 Amp trickle charge. It never occurred to me that there would power going from the leisure batteries to the engine side.
A/h leisure batteries, it was dusk at the time not much coming from the solar but I was on electric hook up with a 25a ctek charger connected directly to the leisure batteries. It is a hymer so there is also an ebl charging both sets of batteries, the ebl is not good enough to charge 220 a/h on its own, there is also a cable going from the solar controller to the starter battery for a 1 Amp trickle charge. It never occurred to me that there would power going from the leisure batteries to the engine side.