I thought that, after all this time, I should provide an update.
Basically, this seems to have been down to a bad battery. No further problem (apart from a parasitic loss on the battery) after I replaced the battery. Also, because I don't use the truck very often, I've now got a full-time battery conditioner on it.
Basically, this seems to have been down to a bad battery. No further problem (apart from a parasitic loss on the battery) after I replaced the battery. Also, because I don't use the truck very often, I've now got a full-time battery conditioner on it.