Papelione Posted August 22, 2020 Author Share Posted August 22, 2020 Like I said, I hope this helps. The '84 & '85 books are not much different, except the 302 could have fuel injection, so many pages there... Hi Ok, new fuse in slot 17, old was ok , but still. New main light switch installed. No power in fuse 17 slot in run, Guess there should be right? If so, guess this were the problem lies, and I need to track T/W back through harness to the battery. Most likely it´s been touched when I was tinkering with the key start vs external button start. Will keep you posted. /Christian Link to comment Share on other sites More sharing options...
kramttocs Posted August 22, 2020 Share Posted August 22, 2020 Hi Ok, new fuse in slot 17, old was ok , but still. New main light switch installed. No power in fuse 17 slot in run, Guess there should be right? If so, guess this were the problem lies, and I need to track T/W back through harness to the battery. Most likely it´s been touched when I was tinkering with the key start vs external button start. Will keep you posted. /Christian Hey Christian, 17 gets power from the main light switch. Have you checked it with the the headlights on? You are correct - "main light switch" is the one you pull the knob out to engage. Or twist for dome. Next to the wiper switch. Link to comment Share on other sites More sharing options...
Papelione Posted August 22, 2020 Author Share Posted August 22, 2020 Hey Christian, 17 gets power from the main light switch. Have you checked it with the the headlights on? You are correct - "main light switch" is the one you pull the knob out to engage. Or twist for dome. Next to the wiper switch. Yes, headlights on and key in "run" no power in fuse 17:nabble_smiley_cry: But if T/W has no power, main light switch has no power and headlights would not be on right? And fuse 17 is only inst panel. /Christian Link to comment Share on other sites More sharing options...
kramttocs Posted August 22, 2020 Share Posted August 22, 2020 Yes, headlights on and key in "run" no power in fuse 17:nabble_smiley_cry: But if T/W has no power, main light switch has no power and headlights would not be on right? And fuse 17 is only inst panel. /Christian The headlights are fed via fuse links. How does fuse 4 look? Link to comment Share on other sites More sharing options...
Papelione Posted August 22, 2020 Author Share Posted August 22, 2020 The headlights are fed via fuse links. How does fuse 4 look? Blown, and blows the new fuse I replaced it with..... Link to comment Share on other sites More sharing options...
kramttocs Posted August 22, 2020 Share Posted August 22, 2020 The headlights are fed via fuse links. How does fuse 4 look? With the light switch you have 3 circuits coming in and 4 going out. 1. (B) this is the headlight circuit coming from the fusible links (hot at all times). It goes out via H 2. (A) this is the parking lamp and instrument illumination circuit coming in from fuse 4 (hot at all times). It goes out via R or I. R goes to the parking lamps and I goes to fuse 17 and then to the instrument illumination. 3. (D1) this is the dome/courtesy/cargo circuit coming in from fuse 8 (hot at all times). It goes out via D2 to the various dome, map, cargo, etc. Link to comment Share on other sites More sharing options...
kramttocs Posted August 22, 2020 Share Posted August 22, 2020 Blown, and blows the new fuse I replaced it with..... Is your headlight switch 'dimmer' in the dome on position? In other words is it rotated counter clockwise past the click? If it is, rotate it clockwise to get it out of there. That will rule out that circuit. Did it also blow fuse 17 (if the headlight switch is pulled out)? Or did 4 blow even with the headlight switch completely off and not in the dome position? Link to comment Share on other sites More sharing options...
Papelione Posted August 22, 2020 Author Share Posted August 22, 2020 With the light switch you have 3 circuits coming in and 4 going out. 1. (B) this is the headlight circuit coming from the fusible links (hot at all times). It goes out via H 2. (A) this is the parking lamp and instrument illumination circuit coming in from fuse 4 (hot at all times). It goes out via R or I. R goes to the parking lamps and I goes to fuse 17 and then to the instrument illumination. 3. (D1) this is the dome/courtesy/cargo circuit coming in from fuse 8 (hot at all times). It goes out via D2 to the various dome, map, cargo, etc. Hi Ok that explains why circuits B and D1 are untouched by a short in A. 17 does not blow, 4 only blows when headlight knob is pulled. Dimmer in off, (cargo and dome off), no change. Kramtocs :thank you, much appreciated. Night has come in Norway, and I bid you all a good saturday in the US. To continuied in the morning /C Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted August 22, 2020 Share Posted August 22, 2020 Is your headlight switch 'dimmer' in the dome on position? In other words is it rotated counter clockwise past the click? If it is, rotate it clockwise to get it out of there. That will rule out that circuit. Did it also blow fuse 17 (if the headlight switch is pulled out)? Or did 4 blow even with the headlight switch completely off and not in the dome position? Scott, thanks so much for offering Christian a hand with this. I've been busy roughing in a dual vanity, since my parts came wrong. ☹️ Hopefully Christian can get this solved tomorrow. Link to comment Share on other sites More sharing options...
kramttocs Posted August 22, 2020 Share Posted August 22, 2020 Scott, thanks so much for offering Christian a hand with this. I've been busy roughing in a dual vanity, since my parts came wrong. ☹️ Hopefully Christian can get this solved tomorrow. Happy to help! We are getting definitely getting closer. Here are just some thoughts and how I would go about it. Others may have more efficient ways. No cab marker lamps so that can be ruled out No body marker lamps so that can be ruled out Trailer package? The front side markers and parking lamps are continuous so I would twist the sockets out of the lenses and inspect. Follow the wiring on either side back to the firewall and inspect the whole way. Disconnect C1002 at the rear crossmember. This will eliminate the rear parking lamps and license plate lamps. Watch your knuckles when pulling this connector apart. Test after doing this. If the fuse blew, disconnect C121 below the brake booster to eliminate the entire rear circuit. Test after doing this. If the fuse blew even with C121 disconnected then it's back to the front side and parking lamp circuit which involves inspecting under the dash since the passenger side wiring crosses over inside the cab The buzzer circuit is also part of this but I would think it the least likely cause My gut feeling, just because there has already been one issue at the rear taillights, is that disconnecting C1002 will prevent the fuse from blowing at which time you can pull the taillights and inspect. You don't have to disconnect if you would prefer to pull the taillight housings instead and inspect. Link to comment Share on other sites More sharing options...
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