Gary Lewis Posted January 25, 2021 Author Share Posted January 25, 2021 904 comes in from the right [continued on of 18] 904 needs to come straight across and splice (Sxxx) into the regulator plug of the 3G. I don't know what to call that splice, so I call it Splice xxx. John - This is just a test of how to show things. But we need: 1G without shunt and ammeter 1G without shunt but with voltmeter 1G with shunt and with voltmeter 1G with warning light 2G without shunt and ammeter 2G without shunt but with voltmeter 2G with shunt and with voltmeter Note that the 2G came out in '86, which was the first year they discontinued the warning light. Jim - I understand what you are saying. Show the splices rather than just continuing the wires. Got it. Ok, I'll do some more Link to comment Share on other sites More sharing options...
85lebaront2 Posted January 25, 2021 Share Posted January 25, 2021 John - This is just a test of how to show things. But we need: 1G without shunt and ammeter 1G without shunt but with voltmeter 1G with shunt and with voltmeter 1G with warning light 2G without shunt and ammeter 2G without shunt but with voltmeter 2G with shunt and with voltmeter Note that the 2G came out in '86, which was the first year they discontinued the warning light. Jim - I understand what you are saying. Show the splices rather than just continuing the wires. Got it. Ok, I'll do some more The problem with taking the shunt out is twofold, (a) the printed circuit on the cluster will not take the current output of the 3G even a 95 amp, it is designed to handle a very small differential between the alternator/battery and the load. (b) the ammeter is also only designed to handle the small differential and without the shunt it will be a moot point what burns up first, the wires to the dash, the plug(s) on the cluster, the printed circuit or the ammeter itself. Gary, look at your Chrysler electrical, they used a real ammeter, but due to the way it is hooked up it has some interesting behavior. It is great if you understand it shows not into or out of the battery but alternator output. Link to comment Share on other sites More sharing options...
Gary Lewis Posted January 25, 2021 Author Share Posted January 25, 2021 The problem with taking the shunt out is twofold, (a) the printed circuit on the cluster will not take the current output of the 3G even a 95 amp, it is designed to handle a very small differential between the alternator/battery and the load. (b) the ammeter is also only designed to handle the small differential and without the shunt it will be a moot point what burns up first, the wires to the dash, the plug(s) on the cluster, the printed circuit or the ammeter itself. Gary, look at your Chrysler electrical, they used a real ammeter, but due to the way it is hooked up it has some interesting behavior. It is great if you understand it shows not into or out of the battery but alternator output. Bill - I think you missed something - we are also taking the wiring to the ammeter out. No juice to the ammeter. All - See what you think of this. I've tried to do some highlighting of the new wires. Also, what do you think of saying the shunt should be replaced with a #6 wire? That may be overkill, but #37 is a 10 gauge wire and #38 is a #12. And the shunt replacement needs to power both of those wires - all everything in the cab. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted January 25, 2021 Share Posted January 25, 2021 Note that the 2G came out in '86, which was the first year they discontinued the warning light. My '87 had a 2G and a warning light. (Of course all '87-> trucks had a voltmeter) Even my lowly 'Custom' Yeah, you can't have a functional stock ammeter and no shunt. Without a way to provide voltage drop around the meter, it won't read. And with 100A+ passing through the meter, it is going to melt. Link to comment Share on other sites More sharing options...
85lebaront2 Posted January 25, 2021 Share Posted January 25, 2021 Bill - I think you missed something - we are also taking the wiring to the ammeter out. No juice to the ammeter. All - See what you think of this. I've tried to do some highlighting of the new wires. Also, what do you think of saying the shunt should be replaced with a #6 wire? That may be overkill, but #37 is a 10 gauge wire and #38 is a #12. And the shunt replacement needs to power both of those wires - all everything in the cab. Probably would do it, what size is the wire from the battery to the PDC on BB? I would use that as an idea, but it might be overkill. You are still limited by the inside the cab wiring components, like the ignition switch. The 1996 uses two 12ga fuse links from the battery into the #37 yellow wire to the PDC. There is another 12ga for the alternator. The ignition switch on the 1996 has two 50 amp fuses and one 20 amp fuse feeding it. The 1985 has everything through the ignition switch on that one fusible link so #6 might be overkill, but better than having something melt underhood. Link to comment Share on other sites More sharing options...
Gary Lewis Posted January 25, 2021 Author Share Posted January 25, 2021 Probably would do it, what size is the wire from the battery to the PDC on BB? I would use that as an idea, but it might be overkill. You are still limited by the inside the cab wiring components, like the ignition switch. The 1996 uses two 12ga fuse links from the battery into the #37 yellow wire to the PDC. There is another 12ga for the alternator. The ignition switch on the 1996 has two 50 amp fuses and one 20 amp fuse feeding it. The 1985 has everything through the ignition switch on that one fusible link so #6 might be overkill, but better than having something melt underhood. The wire from the battery to the PDB on the driver's side is a #4, Bill. And it is intended to carry everything in the cab, which is what the shunt's replacement is to do. However, that #4 is pretty long, maybe 6'? And the shunt is maybe 1'. So it really won't take a huge wire. But, if someone is running a killer stereo powered out of the cab, and then A/C, and no headlight harness, and no LED bulbs, plus power windows, there could be a lot of current. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted January 25, 2021 Share Posted January 25, 2021 The wire from the battery to the PDB on the driver's side is a #4, Bill. And it is intended to carry everything in the cab, which is what the shunt's replacement is to do. However, that #4 is pretty long, maybe 6'? And the shunt is maybe 1'. So it really won't take a huge wire. But, if someone is running a killer stereo powered out of the cab, and then A/C, and no headlight harness, and no LED bulbs, plus power windows, there could be a lot of current. Look at the page from the EVTM. It doesn't matter how big (or small) you make the shunt's replacement, as long as it's bigger than the fuse links at the right. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted January 25, 2021 Share Posted January 25, 2021 Bill - I think you missed something - we are also taking the wiring to the ammeter out. No juice to the ammeter. All - See what you think of this. I've tried to do some highlighting of the new wires. Also, what do you think of saying the shunt should be replaced with a #6 wire? That may be overkill, but #37 is a 10 gauge wire and #38 is a #12. And the shunt replacement needs to power both of those wires - all everything in the cab. You're still showing the 610 connector, and the shunt replacement spliced in after. GET RID OF THE ENGINE SIDE OF C610! Unplug it and throw all that crap out, along with the regulator. Either make your new wire with a single pin to join 37 at the cab side of 610, or cut the whole connector out of the truck. It's useless. Link to comment Share on other sites More sharing options...
Gary Lewis Posted January 25, 2021 Author Share Posted January 25, 2021 Look at the page from the EVTM. It doesn't matter how big (or small) you make the shunt's replacement, as long as it's bigger than the fuse links at the right. Yes and no. The fuse links have high temp insulation, which the shunt's replacement won't have. So that wire shouldn't be operated as close to the limit as the fuse links. Maybe the wires after the fuse links are the better things to gauge, pun intended, and they are #12 and #10. I just did a cross sectional area calc, and #12 is .0051 sq inches while # 10 is .0082, which gives a total of .0133. And #8 is .0130. Looks like a good fit. Thoughts? Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted January 25, 2021 Share Posted January 25, 2021 Yes and no. The fuse links have high temp insulation, which the shunt's replacement won't have. So that wire shouldn't be operated as close to the limit as the fuse links. Maybe the wires after the fuse links are the better things to gauge, pun intended, and they are #12 and #10. I just did a cross sectional area calc, and #12 is .0051 sq inches while # 10 is .0082, which gives a total of .0133. And #8 is .0130. Looks like a good fit. Thoughts? Not "Yes and no" The fuse links are supposed to be two wire gauge sizes smaller than the wire they protect. You have 37 & 38. If you look at the stock diagram both are fed from the shunt. Therefore the shunt is fine (with a stock load) Using anything bigger, without hacking into the cab harness and eliminating those fuse links, is a waste that gains you nothing. Link to comment Share on other sites More sharing options...
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