1997 tahoe

left turn signal or cruse control wont work with headlights on but will work with headlights off and also work with day time running lights on. the flashers work fine with or with out headlights on and I have checked all bulbe also notice dash lights pulse with turn signal. serv engine soon light goes on and off says bad o2 heater,converter clutch open circit, open ground on transfere case skid plate D but all seems to rest it self and service engine soon light goes off for a week or so?? also dont know code to diable theft lock for radio if I ever have to disconect the power to anything any help would be great.

I have that pulsing of the lights with my left turn signal. Have you resolved that problem? I spent some time this weekend trying to run down the potential problem and haven't any.