hi bikey
firstly check all your earth points if its a common earth config set up but undo them and clean them before tightening them back up
have you checked the relay for indicators
i dont know what bike it is but its not uncommon to find to circuts using the same relay but in general the indicators have there own
go through all electrical connectors and take them apart and check for moisture if you have an airline and give them a blow and then a spray with wd 40 to help for starters
as for a multi meter red is positive and black negative put the black on a good earth point and check the indicators for voltage when on at the connector if you get a minus reading then you have the probs around the wrong way
do your indicators come on when they are switched off if so i would look at the switch and if all seems fine give them a spray with wd 40 then try the relay
mark2