Hi I have a 2006 daf of 55 220 oil tanker(it has 2 isolator switches both of which seem to be killing power when used), couple of weeks ago it wouldn’t turn on no dash lights etc, can hear lorry “clicking” when key turned but nothing on dash and wouldn’t start, managed to get it to start by earthing the starter relay but lorry won’t charge, no gauges working, indicators not working but head lights will turn on? Any suggestions would be more than welcome. I’ve replaced entire fuse board

Gman1986, July 2022

DAF manuals

https://www.daf.co.uk/en-gb/daf-services/driver-services/driver-manuals

Fghuu, July 2022

You need to find out what these isolators are supposed to do.
It sounds like the battery isn't being charged. An alternator problem possibly or something to do with these isolators.
You need to work out what they are supposed to do.
Are they OEM things? Have that been added as part of the truck being made a tanker? Ar they just something that's been added for some reason?
There are specialist forums for DAF trucks. You'd be very well advised to seek some out and post there.

Tfvhh, July 2022