Motorcycle Repair: turn signals,1990 dr250, turn signal switch, volunteer time

Question
I am helping a friend w/his son's bike[no good turn goes unpunished] he had dropped bike[riding on st.w/a knobby-I installed a "trail wing on rear,and s/w him about knobbies,and semi-knobbies on the st.] and broken rear turn signal. my son [13 yrs] was helping,and,when I was not home,soldered the wires for the replacement baja design signals that I bought,but appears he forgot the pos.and neg need to be separated and joined pos.and neg. now,although connected correctly,none of the turn signal lights work. batterys charged,headligts[high and low]work,tail light and brake light work.I bought a clymer but there is v.little about turn signal wiring,and the wiring diagram is pitiful. He said the signals worked even after he crashed,so I think the prob is due to my sons"helpfulness". the fuses at the battery[2-15amp] look ok. Is there a "flasher",I can't seen to find it?  are there other fuses for this circut? he also said turn signals do not operate unless engine is running,is that true? Is there a terminal at the turn signal switch that is "hot" when key is on? I've worked on hondas,bmw's and even triumphs,and they all seem more straight foward.where would you start? thanks for any help you can provide,rob jones

Answer
Hi Rob,

Your narrative is difficult to read, but I think I understand the problem(s). I may be able to help you.

I return tech information files by email. There was no email address with your question as requested in my instructions. Email makes my volunteer time possible.

Return your email address with your reply. We'll go from there.

Respectfully,
Mark Shively