calling on 1970 DeVille experts - does this starter wiring look original?

[RFelts]

I'm troubleshooting a non-functioning charging system. (I have been looking around and see that there's no dearth of information on that problem, so that's not what this post is intended to address.) While I was under the car checking connections at the starter, I took this picture and I'm seeking opinions on originality. The various connecting wires from the harness run through this stiff white plastic shield, which is itself behind a metal heat shield protecting it from the exhaust. Is this how Cadillac built it? Thanks in advance for your thoughts!

["Cadillac Kid" Greg Surfas 15364]

Without any doubt there has been some wire replacement. If nothing else the original wiring was color coded. Is everything functional?
Greg Surfas

[RFelts]

It starts, although the starter doesn't reliably engage. Accessories (e.g., windows, lights, etc) work. As I said before, the charging system isn't working.  I'm puzzled by how well done this wiring appears if it's not original, but I take your point on the color coding, which is part of the reason I posted, to see if others who have first-hand experience with a '70 DeVille could shed light on what colors of wire I should find. The main battery cable is black, and all others red except for one green...not what I expected to see.

["Cadillac Kid" Greg Surfas 15364]

Without a doubt, a Factory Service Manual is in order.  They are available in original or reprints and include all the techniques and tasks you are going to need with your car. You will find the starting and charging system wiring diagrams and all the components so you can self verify if everything is as and where it is supposed to be
Greg Surfas

[RFelts]

Thank you, Greg. I ordered a reprint of the service manual yesterday, but it'll take about 10 days to get into my hands...

I'm so excited to work on this car, I can't wait for it.  ;-)

[RFelts]

By the way, my question is motivated by a desire to ascertain whether this is a very low mileage original car or an older restoration. The underside of this car appears to have never seen a wet road. I just bought it Friday, and the seller didn't represent it as a low mileage car, but he had only owned it a short time and never titled or registered it - I'm not sure he knew what he had. He provided no records with the car.

The tires on the car are 30 years old (3590 date code, i.e., 35th week in 1990) and show little wear. I pulled a wheel cover and was stunned at the condition of the wheel. The car was last titled in 2010, and it has only clocked 1100 miles since then.

If the car is an old restoration, I'll feel much less obligated to preserve original parts and fittings, which is why I'm trying to ascertain originality. If it's a low mileage unrestored car, I don't want to start carving up the wiring harness.  :-)

[TJ Hopland]

I think I can make out the word fuse on the red wires in the starter photo.  At least 3 of those should be fusible link wires.  4th I'm not sure about and the 5th wasn't so maybe that is the green one.   

I don't know 70 specifically but that era typical GM there were 5 small wires at the starter.   3 fusible link wires went to the big battery terminal lug.  There was about 1 foot of fusible link wire that then spliced into regular wires and went into a main harness.  There is a wire going to the S terminal which is your start signal from the key, I'm gonna guess maybe this is the green one in your case?   The last wire is on the I terminal, this sends battery power direct to the ignition coil during cranking to give it a little boost.  It bypasses all the rest of the wiring and key and ballast resistor and such.  I'm not sure if factory had a fusible link wire there or not, it would make some sense to have it there because it would not be fused in any other way. 

The 3 wires from the battery were one to the headlight switch for headlights (not running, tail, or turn signals).  Two was  to the fuse box for the stuff that was always on.  Three went to the key and then to the rest of the fuse box for things that were only on with the key.   

73 had a 6 pin connector (one blank pin) around the area of the splice between the link wires and regular wires,  not sure what other years they did that.  If 70 had that perhaps that was a problem area and they eliminated that connector with the repairs?   Maybe after changing a starter the harness and connector melted into the exhaust?   I know they didn't use that connector for that many years.   Not that far from the road so could get wet and grime and wasn't waterproof and also was close to the exhaust. 

[RFelts]

Thank you, TJ. Your response is very helpful - I hadn't considered that I may be looking at fusible links, but that is certainly inscribed on them. I'll look for the six pin connector at the other end of the white cable shield they run through next time I'm under the car.  I see no evidence of any wire splicing and wonder if this is the original starter.

[TJ Hopland]

I believe at least slightly later the factory fusible link wires were different sizes and different colors, at least one of them was, 2 may have been the same.    Universal replacement link wire comes in like 25' rolls maybe they ran link wire all the way to where it was going which I think would have been the bulkhead firewall connector in the case of most of these wires?   I'm assuming a 70 had one of those.  73 did and the connector is basically the back of the fuse box.   

You could also look at the ignition coil + wire.  If there is 2 wires on the + terminal is one of them red fuse wire?   If one wire can you follow it till it splices to 2 wires and then is one of those the red wire?  One there are 2 wires one should be an odd looking solid feeling core (as opposed to stranded like the rest of the wires) with a almost cloth like insulation.  This is the ballast resistor wire which likely goes to the bulkhead connector and eventually to the key.  The other wire would be the one down to the I terminal on the starter. 

I believe there is a chart and formula saying exactly how long a fusible link wire should be vs its size vs the rest of the wires in the circuit vs the load.   Several feet isn't correct unless maybe they were trying to avoid buying the correct size wire and a longer length maybe equals the smaller wire?    Generally you go two sizes smaller than the rest of the wire so if its a 10 gauge wire feeding the fuse box you would use a 14 gauge link wire.   For the most part wire sizes are even numbers so the size you are skipping is 12 since there is no 13 or 11.    Some places say the wire should be 9" and others 12".   I don't remember where I read the actual formulas but most of the time they basically tell you 2 gauge sizes and less than a foot.

[fishnjim]

If you can not wait, those wiring diagrams are on-line.   Just google 1970 wiring diagram.
Should give the color and size with the legend.

[fishnjim]

With 30 year old date code tires with little wear, that means it has not gone far since 1990.  So that checks, with odometer and registration/mileage.
Without further documents or previous owner testimony, your not going to be able to answer your question conclusively.
That leaves what happen during the previous 20 years, 70-90, and does the wear and mileage look consistent.   Depends where and how it was stored and a few other variables, if it can be authenticated.   If you dont; have the build sheet, for $50 you can get one from GM heritage center.   That'll tell what should be on it and if it matches.
I'd look hard at the paint.   That's the best way to figure out if it's orig or restore.   Look for evidence of fade, overspray, color change, sand scratches, or more than 3 layers.  Anything that wouldn't have left the factory.   May have to remove a few trim parts.   The old magnet and paint thickness meter is another tool, looking for evidence, positive and negative.
In order to be low miles, unmolested, it has to show the proper/matching level of wear.
Upholstery tells a lot.   Any place driver puts hands, etc. wear through?   Elbow spot on the door, rest, etc.
Look for cleanliness/lack of brush/wear dust in the electrical parts, like inside distributor, commutators, and pulleys for wear.   Those clues should help.   Check the part numbers and casting numbers for correctness.
Wirings already been covered.
You could spend a few bucks and get it independently appraised, and that would add to the story.

[chrisntam]

Look for wear or lack of on the brake and gas pedal pads.