73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Electrical => Topic started by: swilliams on November 29, 2016, 03:48:10 PM
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I am trying to do more of my favorite{NOT}wiring. In my fuse box i have several "Shunt" place fillers. I guess? What (http://i36.photobucket.com/albums/e42/swilliams19733/6D7E1655-707E-4C43-A407-63B7C9A5904B_zpszvpkvytj.png) (http://s36.photobucket.com/user/swilliams19733/media/6D7E1655-707E-4C43-A407-63B7C9A5904B_zpszvpkvytj.png.html)are they can they be removed or what are they for?
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The "shunts" are jumpers that connect circuit gangs behind the fuse box. Removing a 'shunt' will defeat any associated power taps and may include a couple of fuses.
Substituting larger capacity fuses as you have invites catastrophe! The wiring associated with a given fuse capacity is "gauged" to correspond to the rating of the fuse. Installing a larger capacity fuse without upgrading the associated wiring can result in overheating and electrical fire. You need to rethink your strategy.
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To keep from doing what I have done in the pic below the shunt can i stab wires coming through the fire wall untill i find a switched and splice in there? Sorry wiring is not my cup of tea.
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If you need a high current ignition source, rather than interfere with the existing wiring, install a 70-amp relay in a convenient location. The relay can be switched ON by connecting its coil leads between ground and one of the ignition tap cavities at the top of the fuse box. Load power can be fed to the relay via a heavy gauge cable connected directly to B+ through an appropriately sized fusible link. Ignition controlled accessories can then be connected to the opposing power lug of the relay through individual fuses.
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I think that is more than i need. Here is the statement from the installation instructions.
Before beginning the installation, we recommend that you locate a CLEAN
Switched 12v Ignition source. This source needs to have 12v while cranking, and with
the key in the run position. Label this source now, as you will need to use it for Step 9.
Do NOT Connect the switch 12v wire to a source such as the ignition coil, or starter
solenoid.
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Taken out of context (what's the application?) and w/o any indication of current demand (again, what's the application?) the instructions aren't very revealing. That entire paragraph just states you need a 12 volt ignition source. I recommended 70 amps because you have a 40-amp fuse in a 20-amp ignition location - not-to-mention the 30-amp fuse in a 20-amp battery location. A 70-amp capacity could easily handle that 40-amp burden plus allow for future growth. If you think it's too much, use a lower capacity relay and wiring. But, the concept remains the same.
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Here are the entire instructions.
http://documents.holley.com/199r11031r.pdf
When you talk about adding the relay if its the 4 pin type canyou tell me the numbers on the relay and which one goes where. What type of connector goes into the ignition tap cavities.
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The Holley ignition connection is low current, probably between one and three amps.
The most common relay configuration (images) uses terminal numbers 85 & 86 = coil terminals (unless the coil is shunted by a diode, connection polarity is arbitrary); 30 = common (generally B+); 87 = normally open (the most common load connection); 87a = normally closed (generally unused when present - often absent).
The "ignition" cavity connector carries original GM #12004888 (single) and 12004892 (multi), Color: natural
Available from American Autowire (P/N 500429 (https://www.americanautowire.com/shop/nsearch/?q=500429)) as part of an ATO fuse box connector kit complete with Pak-Con terminals. Each color connector indexes with specific cavities in the fuse box. The ignition cavities use the natural (clear) connectors.
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Thank you for your help once again.
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This diagram of the 5 prong relay saved me today. I was able to troubleshoot two bad relays and replace them.