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For those interested, I've attached a picture of the shunt splice shown on the 66 schematic. I removed the background for clarity and tried to save it as a jpg so it would display in the post. For some reason, it kept saving as a pdf even though I selected the jpg export option. Go figure. Anyway, the splice was located in the main bundle that runs along the firewall. I cannot be more specific because I removed the bundle from the car. Looking at the schematic, there is a small text block in the lower right corner that indicates a default wire size. I cannot get clarity to tell for sure, but I would assess the default wire size is 16 ga. The text looks like it could be 16 or 18, and I think 18 is too small. Can anyone verify the default wire size? Thanks.
MajD
Last edited by MajD; May 26, 2026 at 09:45 AM.
Reason: misspelling
For those interested, I've attached a picture of the shunt splice shown on the 66 schematic. I removed the background for clarity and tried to save it as a jpg so it would display in the post. For some reason, it kept saving as a pdf even though I selected the jpg export option. Go figure. Anyway, the splice was located in the main bundle that runs along the firewall. I cannot be more specific because I removed the bundle from the car. Looking at the schematic, there is a small text block in the lower right corner that indicates a default wire size. I cannot get clarity to tell for sure, but I would assess the default wire size is 16 ga. The text looks like it could be 16 or 18, and I think 18 is too small. Can anyone verify the default wire size? Thanks.
MajD
So, you mean you found it in the engine bay side of the firewall? It appears to be one large wire on one side of the splice with several on the other......do I have that right? I would imagine that the large red wires going into that splice are more like 10 gauge. I know the wiring diagram says something about the default wire gauge being 16 or 18 gauge or something like that but not here. The red wire coming off the alternator goes to that shunt splice and I reckon it's a 10 gauge, maybe 12.
In any case, this is really good info thank you so much for posting it.
In this area somewhere? Yeah, mine is covered in loom currently.....I will fix it at some point.
Last edited by ourkid2000; May 26, 2026 at 09:54 AM.
Yes, it was on the engine bay side, but cannot say for certain where, as I didn't find the shunt until I pulled the bundle out of the car. I would guess it's not too far from where you indicate. The way it is spliced together from what I can tell is that all the red wires in the engine bay are on the same side of the splice as the large feed wire from the alternator. All the red wires going into the cabin are on the other side. That's the way is seems to me but I can send ore pictures from different vantages if that would help.
Hopefully providing some clarity to this thread by inserting an image from the 1966 Oldsmobile Toronado wiring diagram already provided by ourkid2000 (in another post). We/I/Someone might consider a modest combination of threads/posts which may assist in identifying this good information.
Yes, it was on the engine bay side, but cannot say for certain where, as I didn't find the shunt until I pulled the bundle out of the car. I would guess it's not too far from where you indicate. The way it is spliced together from what I can tell is that all the red wires in the engine bay are on the same side of the splice as the large feed wire from the alternator. All the red wires going into the cabin are on the other side. That's the way is seems to me but I can send ore pictures from different vantages if that would help.
MajD
That's awesome! Yes if you could get a few more snaps of the shunt splice maybe we can identify which wires go where. Whenever you get a chance, thanks again! Excellent work.
Can anyone confirm the default wire size in the lower right hand side box? In that picture ourkid2000 sent, it looks like 18 ga. Of course there are circuits with larger wires, but only a few of the different wire sizes are shown in the diagram. I know from looking at the bundle that there are more wires over 18 ga than listed on the drawing. I have the reproduction chassis manual, but the box text on that diagram isn't any clearer. Thanks.
Select years the default statement did not appear, in other years it appeared. Historically what I've noticed are original wiring diagrams from very early years were (1) not color (2) wire gauge labeled in B&W (3) no default statement(s). Most of these diagrams were obviously only produced in B&W ink for viewing on a paper product. Next, came development of color wiring diagrams and various formats of labeling wiring w/ and/or w/o gauge sizes. Again, these were for printed documentation. So, you had B&W format>Color format, changes to gauge identification/formatting (styles), etc. None were developed specifically for digital display on a computer. Albeit, as time progressed you note changes.
And, nomenclature changed over the years in subtle and not so subtle ways. The propeller shaft gave way to the drive shaft, the generator took a course all its own referred to in manuals as a generator when in fact it was an alternator yet the dash idiot light and select documentation referred to the beast as a generator, the horn relay junction/distribution block was at one point referred to as the PTO (Power Take Off). And, of course one could only hope the person creating the documentation had some knowledge of exactly what the documentation was supposed to represent (two different jobs). In some manuals they spell it GUAGE in others they spell it GAGE.
Can anyone confirm the default wire size in the lower right hand side box? In that picture ourkid2000 sent, it looks like 18 ga. Of course there are circuits with larger wires, but only a few of the different wire sizes are shown in the diagram. I know from looking at the bundle that there are more wires over 18 ga than listed on the drawing. I have the reproduction chassis manual, but the box text on that diagram isn't any clearer. Thanks.
MajD
I really don't understand why they bother with that 18 gauge statement honestly. The wiring diagram is full of wires that are much larger than 18 gauge and they're not marked as such. The red wire coming off the alternator, for example, is a big one.......not marked, leading you to believe it's an 18 gauge but when you look it's clearly more like a 10 gauge. I don't think any of the wires going into the shunt splice are marked with their gauge, actually, and almost all of those are very large gauge wires.
I've looked at both my original CSMs over and over, with reading and magnifying glasses, and all I can say it that the number appears more to be 18 than 16.
Also interesting that so very few odd size wires are called out - only 2 gauge positive battery cable, 14 gauge horn wires, and 12 gauge starter solenoid wire - really surprised that alternator output wire(s) not called out.
Is this where Joe_Padavano or another member chimes in w/ some Service Bulletin describing an update to the original 1966 Oldsmobile Toronado wiring diagram? LOL
Is this where Joe_Padavano or another member chimes in w/ some Service Bulletin describing an update to the original 1966 Oldsmobile Toronado wiring diagram? LOL
Yeah, it's called the 1967 Toronado CSM wiring diagram.....which still has the same problem haha. I have the '67 diagram as well here and it fixes some of the problems with the '66 diagram but not all.
Yeah, it's called the 1967 Toronado CSM wiring diagram.....which still has the same problem haha. I have the '67 diagram as well here and it fixes some of the problems with the '66 diagram but not all.
Curious about something. I don't know much about Toronado wiring/gauges; but does a 1967 Toronado have a Ammeter? I'm only asking for a selective reason based upon incorporation of a shunt into the wiring diagram(s). Unless you have a Ammeter I'm not convinced there's much need for a shunt.
Curious about something. I don't know much about Toronado wiring/gauges; but does a 1967 Toronado have a Ammeter? I'm only asking for a selective reason based upon incorporation of a shunt into the wiring diagram(s). Unless you have a Ammeter I'm not convinced there's much need for a shunt.
Yeah there's an ammeter. It's shown on the wiring diagram up at the top.
The ammeter, in these cars at least, is more like a milli voltmeter.......it measures very the small voltage drops across the shunt wire and displays it as either discharge (- voltage) or charging (+voltage). I hope that makes sense.
Yeah there's an ammeter. It's shown on the wiring diagram up at the top.
The ammeter, in this car at least, is more like a milli voltmeter.......it measures very the small voltage drops across the shunt wire and displays it as either discharge (- voltage) or charging (+voltage). I hope that makes sense.
Makes perfect sense (both figuratively & literally). Wonder what year the Toronado ditched the Ammeter? Likely the shunt was no longer employed.
Here's the '67 wiring diagram out of the 1967 CSM. An acquaintance snapped a picture of his CSM and sent it to me. I don't know why it attaches upside down. When I open it here it is correct but when I post it.....upside down.
In 1968 they went to the light if I'm not mistaken. The '69 definitely had a light and it's just about the same car.
I suspect neither the 1968 nor the 1969 Toronado wiring diagram has a shunt. I might take a look later if I can identify a Toronado wiring diagram. Thanks.
Thanks everyone for all the useful information. I think I will use the fuse sizes and a wire gauge measuring tool to determine the wire gauges I'm going to use. It seems 18 ga will suffice for most of the circuits, but the A/C, Power Seat, ignition switch, solenoid, and red power wires are likely larger. When I get back at it, I'll try and get some more pictures of the splice shunt. Thanks for converting the one I sent...it's always easier to see the picture in the post. Hopefully I can figure out how to get the file formatted correctly. I'll keep everyone posted as I start the repairs.
Thanks everyone for all the useful information. I think I will use the fuse sizes and a wire gauge measuring tool to determine the wire gauges I'm going to use. It seems 18 ga will suffice for most of the circuits, but the A/C, Power Seat, ignition switch, solenoid, and red power wires are likely larger. When I get back at it, I'll try and get some more pictures of the splice shunt. Thanks for converting the one I sent...it's always easier to see the picture in the post. Hopefully I can figure out how to get the file formatted correctly. I'll keep everyone posted as I start the repairs.
MajD
Thanks again! Looking forward to your updates. You're doing great work for us all!
I pulled apart the bundle at the splice connection and measured the wire sizes. Here are the results:
All wires in the bundle passing through the fire wall (not counting the separate signal and headlight bundle) are 18 ga except for the following:
The large purple wire is 14 ga
The brown and white wire in my bundle was a solid wire about 24 ga
Green wire was 20 ga
Red wire to lights was 14 ga
Red wire to ignition was 12 ga
The shunt splice presents a little bit of a mystery when compared against the schematic. The schematic shows six wires at the shunt, but the picture shows seven; and there is black wire when the picture shows none. I think I have an explanation for both of these. The four wires on one side of the shunt go to the fuse bus, the ignition switch, the light switch, and the amp meter. On the schematic, that wire is black, but I had to remove a red wire from a gauge cluster plug to get the bundle out. The schematic shows no other red wires going to the gauge cluster plugs. Second, there is another splice shown on the alternator wire that goes to the regulator. I believe the small wire on the three wire side of the splice goes to the regulator, unless someone knows this would cause a problem with voltage regulation by moving that splice on the schematic to the shunt.
Once again I was not able to convert the picture to a jpeg. Apologies.
MajD
Last edited by MajD; Yesterday at 04:34 PM.
Reason: added right parenthesis
Yeah there's an ammeter. It's shown on the wiring diagram up at the top.
The ammeter, in these cars at least, is more like a milli voltmeter.......it measures very the small voltage drops across the shunt wire and displays it as either discharge (- voltage) or charging (+voltage). I hope that makes sense.
It took some studying of the schematic drawing, but the ammeter is measuring the voltage change between shunt splice and the junction block, across the red-coded wire between those two locations, not across the shunt splice.
It took some studying of the schematic drawing, but the ammeter is measuring the voltage change between shunt splice and the junction block, across the red-coded wire between those two locations, not across the shunt splice.
Yes that is correct, however that's not what I said. Read it again. I said the ammeter measures the voltage drop across the shunt wire. The shunt wire is the wire between the junction block and the splice.......measuring the voltage drop across the shunt wire only.
Yes that is correct, however that's not what I said. Read it again. I said the ammeter measures the voltage drop across the shunt wire. The shunt wire is the wire between the junction block and the splice.......measuring the voltage drop across the shunt wire only.
Sorry, but didn't realize that wire was "the shunt wire."
I pulled apart the bundle at the splice connection and measured the wire sizes. Here are the results:
All wires in the bundle passing through the fire wall (not counting the separate signal and headlight bundle) are 18 ga except for the following:
The large purple wire is 14 ga
The brown and white wire in my bundle was a solid wire about 24 ga
Green wire was 20 ga
Red wire to lights was 14 ga
Red wire to ignition was 12 ga
The shunt splice presents a little bit of a mystery when compared against the schematic. The schematic shows six wires at the shunt, but the picture shows seven; and there is black wire when the picture shows none. I think I have an explanation for both of these. The four wires on one side of the shunt go to the fuse bus, the ignition switch, the light switch, and the amp meter. On the schematic, that wire is black, but I had to remove a red wire from a gauge cluster plug to get the bundle out. The schematic shows no other red wires going to the gauge cluster plugs. Second, there is another splice shown on the alternator wire that goes to the regulator. I believe the small wire on the three wire side of the splice goes to the regulator, unless someone knows this would cause a problem with voltage regulation by moving that splice on the schematic to the shunt.
Once again I was not able to convert the picture to a jpeg. Apologies.
MajD
Awesome! Yes, you are correct about that black wire going to the ammeter. On my car it's red, rather than black. Obviously an error in the diagram (yet another one).
With regards to the regulator wire.......interesting. On my car, the red regulator wire is rather large. It shouldn't be one of the small wires going to the splice. It definitely goes to the splice according to the diagram but it's a thick gauge wire. I'll post some pics of mine:
Red wire and black/white wire are the ammeter wires.
Large red wire on the regulator.
Sorry, but didn't realize that wire was "the shunt wire."
Were getting caught up in detail here but I suppose you'd just call it "the shunt". This bugger right here is the "shunt" if anyone is wondering what we're talking about:
I pulled apart the bundle at the splice connection and measured the wire sizes. Here are the results:
All wires in the bundle passing through the fire wall (not counting the separate signal and headlight bundle) are 18 ga except for the following:
The large purple wire is 14 ga
The brown and white wire in my bundle was a solid wire about 24 ga
Green wire was 20 ga
Red wire to lights was 14 ga
Red wire to ignition was 12 ga
The shunt splice presents a little bit of a mystery when compared against the schematic. The schematic shows six wires at the shunt, but the picture shows seven; and there is black wire when the picture shows none. I think I have an explanation for both of these. The four wires on one side of the shunt go to the fuse bus, the ignition switch, the light switch, and the amp meter. On the schematic, that wire is black, but I had to remove a red wire from a gauge cluster plug to get the bundle out. The schematic shows no other red wires going to the gauge cluster plugs. Second, there is another splice shown on the alternator wire that goes to the regulator. I believe the small wire on the three wire side of the splice goes to the regulator, unless someone knows this would cause a problem with voltage regulation by moving that splice on the schematic to the shunt.
Once again I was not able to convert the picture to a jpeg. Apologies.
MajD
I really apreciate you taking the photo for us here, but can anyone else see any color in that photo? I have a bit of a color deficiency with my vision but it seems to me that there's no color in those wires? I can't make anything out at all.
Once again I was not able to convert the picture to a jpeg. Apologies.
This will continue to haunt you moving forward until you address/fix the issue. There are many reasons for this to occur but the simplest is likely going to be your default setting(s) are incorrectly configured or you're (unknowingly perhaps) manipulating your image files via transfer(s) from a mobile device to a PC.
I don't want to take-up bandwidth & detract from the purpose of this thread, but you should address this ASAP. Do an on-line search of "Why does my phone save images as pdf iphone" or something similar (Android), etc. It nearly all cases your "default" settings have changed since I know of no mobile device (iPhone, Android, laptop, tablet) w/ a default setting of save to .pdf. - the default setting is normally set to .jpeg or .jpg. With a little homework you'll get this figured out, but it will continue to haunt you until you make the correct setting(s).
I don't know why it attaches upside down. When I open it here it is correct but when I post it.....upside down.
It attaches upside/down as the result of camera (device) orientation when you took the image (e.g. horizontal vs. vertical). The RAW characteristics of the image are retained & will display the RAW characteristics unless you manually change the orientation via a photo program/application BEFORE you UPLOAD the image. The CO s/w examines the RAW formatting of the image. This formatting is what's retained when you upload an image. Merely manipulating an image w/o saving an image is nothing more than viewing the image. The image needs to be saved with correct RAW imaging characteristics to be displayed correctly. One way to catch this is when (as I stated in How To Post Pictures/Images) Newbie forum is to wait until your images are viewable before you hit UPLOAD:
IMPORTANT: All select files must appear in the following window (below) before you click Upload. Wait until your file(s) are viewable in this window (below) before clicking Upload (see following instructions).
The files will appear and you'll notice if they're upside/down before you hit UPLOAD. It's easy enough to miss (I guess) but it will provide you w/ the orientation you'll see on this CO website when the image(s) are published (posted). If they are NOT in the correct orientation you'll have to rotate the image(s) to the correct orientation (and, importantly SAVE that image on your device) prior to UPLOAD. You can't simply rotate the image until it looks right since you're only viewing the image which then has to be SAVED with its new rotated (RAW) orientation.
It attaches upside/down as the result of camera (device) orientation when you took the image (e.g. horizontal vs. vertical). The RAW characteristics of the image are retained & will display the RAW characteristics unless you manually change the orientation via a photo program/application BEFORE you UPLOAD the image. The CO s/w examines the RAW formatting of the image. This formatting is what's retained when you upload an image. Merely manipulating an image w/o saving an image is nothing more than viewing the image. The image needs to be saved with correct RAW imaging characteristics to be displayed correctly. One way to catch this is when (as I stated in How To Post Pictures/Images) Newbie forum is to wait until your images are viewable before you hit UPLOAD:
The files will appear and you'll notice if they're upside/down before you hit UPLOAD. It's easy enough to miss (I guess) but it will provide you w/ the orientation you'll see on this CO website when the image(s) are published (posted). If they are NOT in the correct orientation you'll have to rotate the image(s) to the correct orientation (and, importantly SAVE that image on your device) prior to UPLOAD. You can't simply rotate the image until it looks right since you're only viewing the image which then has to be SAVED with its new rotated (RAW) orientation.
I didn't take the picture. Someone else did and sent it to me. When I open the file here, it is orientated correctly.....I've never had to play with it. When I attach it on the forum it orientates upside down. So how do I fix that? Open it in a image editor and flip it around and save it in various orientations until it attaches correctly?
I didn't take the picture. Someone else did and sent it to me. When I open the file here, it is orientated correctly.....I've never had to play with it. When I attach it on the forum it orientates upside down. So how do I fix that? Open it in a image editor and flip it around and save it in various orientations until it attaches correctly?
Yes. That's exactly the reason I stated in instructions to wait until the image displays prior to UPLOAD because it will display the RAW orientation of the image. So yeah, you'll need to open the image, rotate to correct orientation and importantly SAVE that newly oriented image prior to uploading (because you want to save the new image in the orientation you want).
I'm learning from what (available) wiring diagrams I've harvested over the years - no, I don't own all the CSM wiring diagrams for all years. With that said....the Toronado is a what - "E" (94 or 96) series, yeah?
I noted the wiring diagram ourkid posted was the wiring diagram for 1967 94-96 series models, so that includes the Toronado, yeah? I'm going to post two (below) wiring diagrams from the 1967 Oldsmobile model years. Note: The ammeter has been removed, the wiring was re-arranged & the shunt removed, to accommodate inclusion of the fusible link...............EXCEPT (evidently) in the 94-96 series models. I always wondered what year(s) this may have taken place...interesting.
Didn't mean to confuse the issue with the regulator wire. It is small compared to the other two wires, but not a small wire when compared to the default 18 gauge. I would say it's probably a 12 ga, but didn't measure it.
The color in that picture is washed out some. All the shunt wires are red, if that's what you're asking.
So after reading the posts about the shunt wire, I want to be clear that it is the wire that charges the battery, correct? And the voltage drop across that wire is what the meter is reading, is that correct?
Vintage Chief, my iPhone takes a picture in HEIC format (whatever that is) and posts it to the cloud. When I retrieve if from the cloud on my MacAir and try to convert it to jpg is when I'm running into the issue. I agree it's annoying and I intend to figure out how to fix it. I just didn't want to leave everyone hanging while I tried to figure that out. Thanks.
Didn't mean to confuse the issue with the regulator wire. It is small compared to the other two wires, but not a small wire when compared to the default 18 gauge. I would say it's probably a 12 ga, but didn't measure it.
I think you're providing more clarity than is currently available on (evidently) incorrectly labeled Oldsmobile diagrams - albeit, any efforts you make in providing more detail is appreciated.
