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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: Mark16B on January 12, 2017, 01:27:53 pm
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I was having problems with my starter, so when I went to remove it I realized it was just old brittle wiring was the issue. However, because the wiring was so brittle it broke before I could get a picture of how it was wired. Any help is appreciated. (https://uploads.tapatalk-cdn.com/20170112/36a75521eaa2811b49872636dbb644ce.jpg) (https://uploads.tapatalk-cdn.com/20170112/e91dd35ec50ae1d9766a6203a009cc3c.jpg) (https://uploads.tapatalk-cdn.com/20170112/8640685f4ee1454f26dece5a173edfc6.jpg) (https://uploads.tapatalk-cdn.com/20170112/0a58765e55ee0d766cb9710ee143dc29.jpg) (https://uploads.tapatalk-cdn.com/20170112/183c54b06df6d01c771eb8562e8cb4d4.jpg)
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(https://uploads.tapatalk-cdn.com/20170112/8640685f4ee1454f26dece5a173edfc6.jpg)
Figure 1
What year/model is this truck? What color is the wire in Figure 1? And, is the wiring harness original to the truck as far as you know?
(https://uploads.tapatalk-cdn.com/20170112/0a58765e55ee0d766cb9710ee143dc29.jpg)
Figure 2
(https://uploads.tapatalk-cdn.com/20170112/183c54b06df6d01c771eb8562e8cb4d4.jpg)
Figure 3
The free ends of the wires pictured in Figures 2 and 3 are fusible links. Cut the wire pair shown in Figure 2 where the two wires enter the splice and install a new 6" length of 16-gauge fusible link terminated by a 3/8" ring terminal - verify that the fusible wire gauge is actually 16 by wiping clean the existing splice and reading the number cast into the splice insulator. Solder and shrink seal the splice and terminal end using How to make a Fusible Link (http://forum.73-87chevytrucks.com/smforum/index.php?topic=11972.msg45217#msg45217) as a reference. I recommend using adhesive lined, dual-wall polyolefin heat shrink, such as Harbor Freight 6759 (http://www.harborfreight.com/42-piece-marine-heat-shrink-tubing-67598.html), because of its superior heat tolerance, abrasion resistance and moisture rejection properties. Similarly, cut the single wire in Figure 3 and install a new 14-gauge fusible link terminated by a 3/8" ring terminal. Both fusible links connect to the 3/8" battery cable stud on the starter solenoid.
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The year model is a 87 Silverado and I believe it is the original harness but am not sure. So after combining the wires in figure 2 and 3 I connect them too the 3/8 stud on the starter along with the large red wire shown here, near the top? (https://uploads.tapatalk-cdn.com/20170113/6963b437935113246abbc52e45cc94a4.jpg) and figure ones wire I know for a fact went to the smaller stud just left of the 3/8 witch I assume is a ignition wire? It is a black wire.
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DO NOT combine the wires in Figures 2 & 3. The two wires in Figure 2 connect to the 3/8" solenoid stud via a 16-gauge fusible link. The single wire in Figure 3 connects to the same 3/8" solenoid stud via a separate 14-gauge fusible link. The red, positive battery cable also connects to the 3/8" solenoid stud.
As for the black wire...
(https://uploads.tapatalk-cdn.com/20170112/36a75521eaa2811b49872636dbb644ce.jpg)
...look at the plastic end cap of the solenoid. The 3/8" stud at the top of the image is the battery connection. The small "S" terminal on the right is the Solenoid connection (purple wire) that energizes the starter during engine cranking. The "R" terminal on the left is generally used only for pre-electronic ignition engines. It is a Resistor bypass circuit for a conventional (points and condenser) ignition coil that becomes "B+" only while cranking the engine. Essentially, the "R" terminal is a 12-volt power source for whatever is connected to it. I recommend that you figure out where the other end of the black wire connects. For example, that black wire either has been added onto the vehicle and powers an add-on accessory only while starting, or it is misconnected to the starter, or the wiring harness is not original to the truck and the other end of the wire doesn't actually connect to anything, etc. Try to figure out what the installer was thinking.
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Chances are the "black" wire is purple, blown exhaust gaskets turn those wire black pretty fast-oil and grease too, scrape the insulation of the wire a little bit to verify
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