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Discussion Starter #1
So I’m installing a new ballast resistor shunt on my 64 SS after a minor meltdown of that & the forward lamp harness. On the re-install, it mounts vertically on the radiator support & there were 3 wires attached to it. I believe it was two connected on top & one on the bottom, is that correct? I took a couple of pictures but missed getting the full complement of how the wires are attached. Any help would be great, thanks!
 

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Hmm, no ballast resitor in a 67 , only a terminal block behind pass headlamps. Resistance wire comes right off the firewall from the bulkhead connector.
 

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Hmm, no ballast resitor in a 67 , only a terminal block behind pass headlamps. Resistance wire comes right off the firewall from the bulkhead connector.

Only '64 Chevelles had this piece Gene. Eliminated in '65.
 

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Discussion Starter #5
Yep, 64 only is my understanding. It looks like 2 go on top & one on bottom but am not positive
 

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Please get me up to speed here but is this "ballast resistor shunt on a 64 SS" for the ammeter gauge ?. OR is it for the ignition coil ?.

With the OP saying it was on the radiator support leads me to believe it's the shunt for the ammeter unless maybe it was for an optional ignition amplifier setup ?.

I'm just not up to speed with everything and this is why I'm asking what I did.

Jim
 

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Please get me up to speed here but is this "ballast resistor shunt on a 64 SS" for the ammeter gauge ?. OR is it for the ignition coil ?.

With the OP saying it was on the radiator support leads me to believe it's the shunt for the ammeter unless maybe it was for an optional ignition amplifier setup ?.

I'm just not up to speed with everything and this is why I'm asking what I did.

Jim

It's a shunt for the ammeter. Not for the ignition coil.
 

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I have to think the the ammeter shunt would wire with one large gauge wire wire going from one terminal on the shunt over to the battery positive post. The other terminal on the shunt would have a short large gauge wire going to the horn buss. You would then have two smaller wires which go to the ammeter gauge and one of the small wires would go to one terminal on the shunt and the other to the other terminal on the shunt.

It sound like maybe the short wire from the shunt to the horn buss is the missing connection.

To word things another way is, the battery is supplying the voltage and current for things and it comes out on a large 10 or 12 gauge wire off of the battery positive post (and some might also have in place a fusible link and junction block off of the battery post and then to this 10 or 12 gauge wire) and now this wire goes over to the ammeter shunt and connects to one terminal on it. On the other end of the shunt a short 10-12 gauge wire goes to the horn relay buss. Then from the horn relay buss a wire then goes back, to and through the bulkhead connector to power other things inside the car.
Now with just this wiring done power can get from the battery,to and through the ammeter shunt and then over to the horn relay and then into the car so everything except the ammeter gauge would work. To complete things to get the ammeter to work the gauge will have to wires off of it with one going to one terminal of the ammeter shunt and the other wire to the other terminal on the ammeter shunt. The possible issue here is getting these two small wires reversed in that if hooked up right with the car off and then the headlights pulled on, the ammeter gauge should read a discharge and if it would not then a simple swapping of the wires would get it to read properly.

The below shows a short jumper wire from the shunt to the horn relay buss. If this is not there, then there would only be three wires to connect to the shunt but things would not work.



Jim
 

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Discussion Starter #10
so there should be two wires going to each terminal/connection? when I disconnected it, the bottom connection of the shunt had one red wire connected to it and it looped around to the front of the radiator support and went across to connect to the extra wire coming out of the positive battery clamp, so that's why I reconnected it that way.
 

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Discussion Starter #11 (Edited)
after getting the new American Autowire front lamp harness, positive battery cable and (fusible link?) wire to the positive battery clamp all installed, I tried to start it and nothing, no click, no turnover, nothing. Not long after trying that, the brake lights worked, then the headlights started working, but still nothing when trying to start. The ammeter would drop down a bit when turning on the headlights or stepping on the brakes and then drop all the way to D when I tried to start it. Thinking I might have fried the external regulator, I replaced that, the condenser and the horn relay...nothing changed, still no start.
 

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Discussion Starter #12
now that I think about it, the wire that I ran from the positive battery post connection did go to the top connector of the shunt, along with a black one, but there is only a single red wire connecting to the bottom and that one is from the new harness. When I disconnected the original horn relay from the burned up harness, I connected it the same way to the new harness before I even started installing the harness on the car, just so I wouldn't connect it wrong.
 

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Below is a variation I would think could be something that might have happened and the wiring was done that way BUT this is only a guess.

In the left diagram you have two wires to each side of the ammeter shunt. On the right side diagram you have one wire to one side of the ammeter shunt but then two on the other side.

I know I've used the AIM for my 68 but what is interesting is on the bottom of some pages they have notes that say things like changed wiring location, or changed this or that, added something, and so on and I have to wonder if the AIM I have is the last one with all of any added notes or changes stated. Maybe I have a mid year manual and later things got changed and no one has this book and has to rely on what has been observed on actual cars through the years.

Anyway. you may have to get more involved and find out exactly what wire end you have and where it actually goes. Maybe too the ammeter shunt you have is bad and instead of the main power going through it to the car to have the headlights work, the brake lights work, and so on, the main power was trying to go through the small ammeter wires and did even additional damage.

If you do get further involved in this, maybe thing about abandoning the ammeter and it's related wiring or if you are dead set on keeping things maybe add fuses and get away from fusible links which to me allow too much current to flow before blowing and allows more damage that what I think should happen to a wire and it's connections.



Jim
 

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Discussion Starter #14
Ok, thanks for all your help, Jim. Much appreciated!
 

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Ok, thanks for all your help, Jim. Much appreciated!

Tony, please follow up & let us know your results. Adding a few pics would be really helpful too, if possible. Thanks. :thumbsup:
 

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Discussion Starter #16
sorry for the delay, bought a new house, sold the old one and between cleaning, prepping, painting and moving, I've been real busy. Got the new front lamp harness installed, did some ohm meter tests and it's all correct, but I don't need the jumper wire, according to my Chevy guru friend who helped me check everything. Apparently, there's a short in the engine harness down by the starter wiring, so I have a new harness for that and I've also decided to replace the dash harness, all at the same time. Looks like it's gonna be a while longer until I get it all hooked back up as I'm doing the instrument cluster and panel re-install and I can't get the panel/housing holes lined up to put in the screws. ugh
 

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sorry for the delay, bought a new house, sold the old one and between cleaning, prepping, painting and moving, I've been real busy. Got the new front lamp harness installed, did some ohm meter tests and it's all correct, but I don't need the jumper wire, according to my Chevy guru friend who helped me check everything. Apparently, there's a short in the engine harness down by the starter wiring, so I have a new harness for that and I've also decided to replace the dash harness, all at the same time. Looks like it's gonna be a while longer until I get it all hooked back up as I'm doing the instrument cluster and panel re-install and I can't get the panel/housing holes lined up to put in the screws. ugh
Congrats on the new house!

Any pics you can share of the installed wiring?
 

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Discussion Starter #18
I'm not sure how to get them from my phone to this site
 

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Discussion Starter #19 (Edited)
so here I am again, still not getting the results I was hoping for. Sorry for the delay, I replaced not only the front lamp harness, but the engine harness, positive battery cable, and the dash harness with all new repop harnesses from M&H and American Autowire. It's taken a while to get them delivered and installed.
I got the car running, but the amp gauge is pegged at D (discharge) and jumps up a little bit when I rev the engine, then right back down to D. I had the battery and alternator both tested and both test good. With the car running, the multimeter says the battery is at 12.6/12.7 volts and stays there.
If I flip the connector over on the back of the amp meter, then the gauge is pegged at C, but the battery still sits at 12.6/12.7 volts. Been worried about leaving the car running too long, don't want to fry anything from overcharging.
It was not there before, so I ran a 12 gauge jumper wire from the bottom of the shunt to the left connector of horn relay as shown in the above diagram and no difference in battery reading or amp gauge.
I also took a Dremel with a small wirebrush attachment and cleaned up all the ground connections, but they may not all be down to bare metal. Does that matter?
If I keep the amp meter connected so the gauge is pegged at C and the battery reads 12.6/12.7 when the car is running, should the battery be charging to a higher reading and the amp gauge dropping little by little as the battery charges up more?
The car doesn't start every time when I try it. Most of the time, its just a one click and nothing. Sometimes, after a few tries/clicks, it will start and sometimes it won't even click, nothing.
The horn relay and the external regulator I installed after the original front lamp harness meltdown are both NOS, the shunt is a new repop, harnesses are all new repops, but the dash gauges are all the original ones from '64. I also installed all new bulbs in the dash harness and new fuses and flasher in the fusebox.
 

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Feels like there's two separate unrelated issues. I think the gauge could be fried, it is almost 60 years old.

The non starting issue concerns me more. If the battery voltage reading 12.7 when the car is running, there is a charging issue. Maybe the battery cable ends are corroded?
 
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