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Home >> GMC >> 1993 >> Forward Control 7.4 N >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Steering Column Switches >> Steering Column Switches >> Testing >> Horn >> Horn Inoperative

Horn Inoperative

  1. Disconnect horn relay. Connect jumper wire between Orange wire terminal and Dark Green wire terminal of horn relay. If horn does not sound, go to next step. If horn sounds, replace horn relay.
  2. Connect test light between Orange wire terminal of horn relay and ground. If test light does not light, go to next step. If test light lights, reconnect horn relay and go to step  4.
  3. Check if horn fuse is blown. If fuse is okay, repair open in Orange wire between horn relay and fuse. If fuse is blown, replace fuse.
  4. Connect test light between Dark Green wire terminal of horn connector and ground. If test light does not light, go to next step. If test light lights, check for clean and tight horn mounting bolts. If bolts are okay, replace horn.
  5. Disconnect turn signal switch connector. Connect jumper wire between Black wire terminal of turn signal connector and ground. If horn sounds, replace horn switch. If horn does not sound, repair open in Black wire between turn signal connector and horn relay.
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