Sorting out issues with non functioning gauges and am on the amp gauge. The horn relay had fried taking out the fuseable links that were immediately connected to the relay, one 16ga. one 20ga. and those I've repaired.
I have 2 wiring schematics I'm working from. One from Classic car wiring is color coded and easy to follow pointing out clearly for this purpose fusable links in the system. specific location in the car is not shown. My Haynes manual is not as nice being printed in black and white but it does show proper wire gauge size which is very helpful.
Using the two I can see the amp meter has 2 leads off of it, one to the horn relay which is black with a white stripe which I have verified continuity in the black and white wire so I know that's good.
The other wire off the amp gauge is solid black 16ga. wire that runs to the bulkhead connector then exits into the engine compartment as a 14ga.black wire that is spliced with a 20ga. orange fuseable link which then is spliced into a red 10ga. wire that runs from the horn relay to the starter solenoid.
(wiring is fun, isn't it ? )
Now I have to assume that a fuseable link would not be taped into a loom so it allows itself to fry if necessary without damaging other wires, it would be logical but not guaranteed.
So, what I'm hoping someone can help me with, where is the location of that orange fuseable link where it connects to the red 10ga. wire that runs from the relay to the starter?
Hoping someone that's deal with this knows off the top of their head.

PS - I saw a post where someone bought the instrument cluster sockets on amazon, what size are they? Do you have the link?

 

What year is the car?
M

 

I assume it's his beautiful '68 BB Convertible.

 

Dormans #85805 is a stock 1 wire replacement

Dormans # 85814 is a 2 wire socket that can have all power and ground wires to a single separate quick disconnect but the plastic socket needs to be trimmed.

 

I'm gonna say that I believe that part of the harness was wrapped and insulated in some fibreglass cloth like the resistance wire was. Crimped connections without the big rubber blocks on them. The others are located close to the starter and the horn relay
M

 

Yup that’s it and thanks for the “beautiful” comment .

 

Thank you Sir

 

Thank you.
I'm inclined to think the problem is with a stuck needle on the amp gauge. I removed it and did a continuity check which it passed but the needle is stiff. Obviously they are fragile but any other amp gauge Ive seen centers itself. If pushed gently to either side it will spring back to center. This one is stiff ans stays to the side. I don't think it can be taken apart and cleaned either as the case is riveted.
A lot of the gauge issues I'm having can be attributed to the prior owner cross threading the brass fitting on the back of the oil pressure gauge which resulted in giving it all including the radio a good oil bath.

 

On more question has come up that you might know, my manual says the instrument bulb is #1895 but I'm finding ones with other letters like N1895, don't know if they are the same. I'm look to buy in bulk like a box of ten to replace them all while I'm in there. Do you know the right number? How about the LED bulbs, any good?

 

Yes it should center itself when disconnected so something else is likely bothering it. If you need to replace it might be worth considering switching it to a voltmeter as well
(I'm not getting into the whole voltmeter vs ammeter thing but replacements are available that should match the rest of your gauges
M

 

I also found this attached to the back of my gauge panel, it’s wire hanging free.
I’m assuming it’s a radio noise suppression filter but not sure and have no idea where it supposed to be hooked up.



On the brighter side I opened up the non- functioning clock to find it very clean but dry inside. The factory owners manual recommends periodic oiling but I doubt that was ever done.
So I oiled it up and gave it power, bam, it works. Left it connected for an hour and it never missed a beat



this is a pic of a short video with the second hand sweeping, it was still too large to attach so take my work for it, it’s working

 

It’s not a concourse car but it is numbers matching so Im keeping it as factory appearing as I can.
Making this a concourse car would be a massive undertaking but I am trying to correct the bad things prior owners have done and for small things it’s been substantial.
With that said I agree 100% with you and would rather have a volt meter. I believe it tells you more about the heath of the charging system.
I’d also rather have an electric sender on the oil pressure gauge and I think the factory agreed it’d be better because they went to it in ‘70.

 

The tick tick tick of the mechanical second hand is somehow more satisfying than the smooth sweep of the quartz conversion clocks (I've got both and used the quartz as it was easier to deal with but liked the tick tick tick movement of the original, now both are on the shelf and a vacuum gauge lives there) While the clock is out fold a piece of fine emery and clean the contacts a bit, that's typically where they get gunked up and don't make contact to start the winder mechanism.
(FWIW, they used the mechanical oil pressure up to 73 and then in 74 went electric)
If you're sticking with the plastic oil line, put some permatex high-temp thread sealant on the fitting threads as some extra insurance, it actually seals against the funny tapered/concave part of the fitting inside the gauge but if it's already been tightened it's been formed a bit, then some behind the ferule on the actual line wont hurt either
M

 

Oh, and that capacitor is a noise filter, should hook into the ammeter connection IIRC
M

 

I don’t see it on any of my wiring schematics. That would do the same thing as the one available that hooks directly to the alternator right ?

 

I have the connector and gauge does seem to be working but with it having been cross threaded and probably over tightened I’m not chancing it. I’ve got a new gauge set (4) and fittings on order for a fresh start. I’ve got the permatex sealant on hand, used it many times.
Made a bunch of orders yesterday and today from a couple suppliers.
Oh as for the tick tick tick, not gonna hear that in this car with the engine running 🙄

 

It would be on the radio or stereo wiring. GM added them to the brake-light switch and a handful of locations to stop the pop in the radios. Most of the ones under the dash are connected with those blue scotch-locs and look like someone added them afterwards but they were GM.

My 72 didn't have the one behind the gauge cluster but I know they had them in C2s and I thought they kept that until 68 or 69
M

 

No but you can see it, only the mechanical ones ticked each second to the next, the quartz just sweeps along in one constant movement, accurate but not nearly as neat as the springs and cogs
M

 

Item 13 down on the bottom here



https://www.corvetteforum.com/forums...post1594121157

https://www.corvetteforum.com/forums...t-cluster.html

https://www.corvetteforum.com/forums...n-my-68-a.html



M

 

That nails it down thank you !