Had the soda blasting, body shop removed all the tail lights, headlights side parking lights, doors including the windshield wiper door, and other items to paint it properly. Great paint job, But wondering if now it will hold up. After I drove it home  I noticed that the horn does not work, three of the tail lights don't work.  Some of the side lights don't work. Turn signals don't work. I checked all the fuses and they are fine.   One headlight only comes on on high beam. The gas gauge is pegged all the way past full. 

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Wow...what a mess, eh?
I would have to start by un-plugging, and then reconnecting all of the lights, one at a time. They may not have gotten everything plugged back in properly. It's also possible they took some ground wires off, and didn't put them back on.
Try checking all of the connections at the lights first, and see how many you can get working just by plugging them in correctly....the fuel gauge, too.


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Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

They really could not have done anything to the fuel gauge. I unpluged the wires going to the sending unit under the gas tank and cleaned the connections  and it is still pegged out. The wires to the tail lights and side lights look okay, but tomorrow I will disconnect them and go by the 68 wiring diagram and see what happens. It has to be a ground  of some sorts for the horn to not be working too.

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I did notice when I put a ground to the one of the fuel gauge connections the gauge returned to normal.

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I have a 1968 and am looking forward to having mine soda blasted in the next 6 to 8 months, you are making me nervous.  Maybe I will just deliver the body only to the shop with nothing electrical exposed.

Having two Corvettes like yourself I have done my share of electrical fixes.  One tool that I found absolutely indispensable was a gadget called a "POWER PROBE".  The Power Probe gets power from your battery and then you go to offending light bulb, motor or switch and it lets you apply 12 volts or ground to the tip and you can tell what is missing.  The newest version has a volt ohm meter built into the probe itself.  If you short out something the built in breaker flips off and you simply reset it.  It has saved me hours on both my 68 and my 88 Vettes.  It is very helpful to see the voltage drop as you follow a particular circuit.  Loose and dirty connections are easily identified as with any good volt ohm meter.

I just updated to the newer version (Version 3)and it came with an "Open circuit" finder and a "Open Ground" finder and has a buzzer that helps you find the disconnected wire or open ground in less than five minutes.

Like others have mentioned to you the grounding system in our older cars can be a real nightmare since we don't have the metal body.  Before your done with all your work be sure to replace your ground straps and clean the body ground to get the best possible results from the wiring system.  I have spent many hours with Emory cloth cleaning the contacts and terminals.  Just be careful that you don't have any connections that are so bad and have sufficient current as to get hot enough to start a fire. It happens on Corvettes more often than we like to admit

I wish you were closer I let you borrow my Power Probe just to prove to you how valuable it can be.  If you want to find a good deal on one go to EBAY and type in Power probe 3 and you will see them ranging from $75 up to close to $250 for the master kit.  The master is the one to have if your finances allow.

By the way, how do you like the 1968 Corvette?  Not many people at the Corvette shows like them, they seem to be the "Rodney Dangerfield" of Corvettes.  Personally I love the fact that it is unique in so many ways.

I wish you the absolute best in solving the gremlins that are playing with you.  I have had my '68 for 19 1/2 years and still love cruising around in it.
Best regards,
CTMcCloskey

As much work as I have done and intend to do on my 68, I will look into the probe. I am not sure yet if soda blasting is the way to go. It is such a mess and really has to be cleaned very well after it has been done to get all the soda off. I just hope my body shop did a thorough cleaning of the top side because they didnt clean much underneath that the soda finds its way into. If you are able to secure the passenger compartment and the wheels and underbody, it probably is a good thing. Other wise I would not do it. However it is a much faster way to get the many years of paint off. 

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I second the nomination of using a Power Probe. Neatest dang automotive electrical tester since the light bulb with soldered wires on it! Test leads are long enough to reach from one end of the car to the other, so you don't have to keep going back/forth.
A little pricey if you don't use them all the time, but well worth it.
Adams' Apple2010-10-29 10:04:08

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Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

I just ordered the power probe and the one for $134.99, not the master, but  one that I hope will help in getting things back to normal. Still with no horn, no brake lights, one headlight not working, fuel gauge pegged out past full. 

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The fuel gauge pegged past fuel means it either has no ground, or the signal wire is not making good contact. Take the signal wire off the sender, and ground it to the frame. See if the gauge returns to normal(it should go to "Empty"). If it does, that tells you the signal wire is good from front to rear. That leaves either the ground wire for the sending unit, or the sending unit itself.

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Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

When I grounded the wire, at the tank the gauge went back to normal. I also took a test light (have not got the power probe yet.) and tested the fuel gauge at the dash on both connections and the gauge went to normal. So I think I have a bad ground somewhere. Since many of the parts were taken off during the paint job and many parts don't work, I just cannot believe it would be the sending unit itself.   Horn, stop lights and right head light on low beam will not work. I guess the stop light switch is burried somewhere up under the drivers side dash area. Have to stand on my head to get to that. 

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All of your electrical issues sound like bad or missing ground connections, except for the head light, it is probably a bad bulb as the high and low beam share the ground. Have you found all the harness ground attaching points? They may just need to be cleaned if still connected to the frame.

Any type of media blasting can be a nightmare to completely remove all of the residue. It will find its way into every crack and crevice and cause problems. I had a 57 truck soda blasted and for years it kept falling out of places. All of the instruments and switches were full of it and had to be cleaned or replaced. Never again, now all paint is removed with sand paper. Very labor intensive but overall it is less work than chasing problems for years after.
I have also tried paint strippers and again it seeps into cracks and can ruin new paint if it is not all neutralized before painting.

How right you are.

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I love my power probe..it works ok on new cars...it is easy to let the smoke out on them though..I can't think of a better tool on an older car to use for electrical problems..they are much more forgiving if you apply power to the smoke wire!
Rich

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My first parade at Carlisle 2010

I haven't figured out all the things the power probe will do as of now, but I was now able to get the horn working, and the brake lights. So tomorrow it is on to the fuel gauge. Plus my battery gauage on the 1968 hasn't worked in a long time, so I will be checking this out too with the power probe.

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I guess the question is do you have an amp gauge or volt gauge? My stock gauge is amp..I have an internally regulated alternator now..the stock one is external..if you have the stock setup ..external..then check the regulator on the fender..if you have a internal style then the amp gauge won't work..as mine doesn't work..I need to switch to a volt style gauge..I have the GM manual for the 69-70..it may be the same for the 68 if you need copies of the ETM side..
Rich

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My first parade at Carlisle 2010

Okay, I have been able to fix the lights , turn signals, brake lights, horn, high low beam lights, and the fuel gauge that was pegged out, the courtesy lights now work too. 

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An amp gauge does not require a ground. It is measuring current thru it. So it is basically installed in-line on the battery cable(alternator, actually, in this case). An amp gauge must have current going thru it for it to work. It will NOT work with voltage. So basically, the way it should be wired is, the large red wire from the alt will go to one side of the amp gauge, and the other side of the amp gauge continues on to the battery. That's a simple explanation of who it is wired, since it is not usually a direct route from one to the other. You have a regulator and fuse box in there, too.
When you replaced you alternator, if it plugged in to the wiring connector on the car without any modifications, then it is prolly the correct type alt for the car.


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Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

By the way, how do you like the 1968 Corvette?  Not many people at the Corvette shows like them, they seem to be the "Rodney Dangerfield" of Corvettes.  Personally I love the fact that it is unique in so many ways.

First off, it's great to see so much good tech info and support for the 68 crowd. I do think the days of "no respect" may be behind us. Most 68's that are still out there have been sorted out and they do have significance IMHO. They are the first year of a truly iconic design. They also happen to be the last year for the 327, a truly iconic engine. I love my 68, although it's turned out to be a much greater investment than I ever thought, but I wouldn't trade the experience for anything. I live in Southern California and I participate in the majority of car shows and drive ins and have only seen 3 or 4 68's in 4 years.  There are a lot more 69- 72's out there (maybe six times as much) so I do think the 68 is somewhat rare. I drive my car at least 50 miles a week and as we all know the older they get the more expensive that is. But the return is pure joy.
Best to C3VR board this holiday season.
John Pratt

Hi John..I am glad to hear another owner as everyone here does appreciate their car..I have seen a bunch of 68 model years around here..I do not think they are a Rodney D car at all..I have fun seeing them as they have a bunch of differences to my late year 69..
Rich

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My first parade at Carlisle 2010

So if I unplug the black wire behind the gauge that goes through the fuse box and splits with one wire going to the solenoid and the other to the horn relay and over to the regulator and on to the  alternator. Then unpug the black and white wire behind the gauge that also goes to the horn relay.

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Well, I hooked up one external wire from the battery gauge to the hot on the alternator. I took the other wire and hooked it direct to the hot on the battery. I started the car, and as I was looking at the gauge I smelled burning elect wires, and then noticed the smoke coming form the console dash area. I turned the car off and started unhooking all the text wires and it  was over. The battery gauge went from center point to all the way over. Fried it and it smelled really bad. So there must be another way of checking out a amp gauge. I will order another one at $59.00 (green face) Like I said before I have two hot wires on this gauge, and I cannot understand why the guage will not work. 

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[quote=Adams' Apple]So basically, the way it should be wired is, the large red wire from the alt will go to one side of the amp gauge, and the other side of the amp gauge continues on to the battery. That's a simple explanation of how it is wired, since it is not usually a direct route from one to the other. You have a regulator and fuse box in there, too.[/quote]

I should have been more specific on that. The amp gauge also has a resistor on it, or it should have. Some are connected across the two terminals on the gauge itself, some are located externally. The black wire on the gauge comes from the horn relay, as does the black/white wire(via the regulator). BOTH have fuse-able links in them...either one should have blown before letting the smoke out of the gauge.
I've hooked many an amp gauge up directly in-line with the alternator, and never had one let go like that. I need to check the wiring diagram...


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Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

That is to bad..one thing I have learned over the years is that there is smoke in the wires and it really gets me peod when I let it out..like Joel said a fuse able link smoked out hopefully..the other thing that I learned over the years is never test anything in the car..whether it be a power window motor or a blower motor..anything that draws heavy amps is coming out..put that power probe to work and figure it out..then collateral damage is minimal..some day I will find out how to put the smoke back in..till then ETM and be careful.
Rich


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My first parade at Carlisle 2010

I think the fuseable links went many years ago and it is just direct from the horn relay amp to the gauge. So to be safe, I ordered a amp gauge and a horn relay. I will be replacing some wires in the area of the horn relay, that had old butt joints in them and are showing their age.. Any suggestion on fuseable links to use. 

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Well I see a few problems that how the smoke said hello..butt connectors work and cannot be soldered when used for high amp parts..the butt connections must be crimped complete and tightly without any movement in them..if you get the gauge out and see burn marks then it made contact with the housing..not sure if that would make a ground or not though..just another path for the power to go..as far as which fusable link to use is a tough one..I know my amp gauge goes to 40..since there is no load on this wire a 40 amp link would work..I looked in my 69-70 manual and it shows a 10 gauge wire for the gauge..I am not sure if the 68 is the same so check a ETM..but a 40 amp one is a 10 gauge if I remember right..do a voltage drop on the wires from the gauge to the relay and alternator..the power probe makes quik work of this..this of course after the wires are repaired..it will find any weak spot or broken wire..you want less than 0,02 drop..any more on these high amp wires and there is to much drop in the wire..be careful..may be a good idea to have a quick disconnect on the battery and an electrical extinguisher handy..the amp gauge isn't worth loosing a car over so don't push it to hard and take your time..
Rich

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My first parade at Carlisle 2010

Hello guys,

A couple more things, How much current does your alternator put out?  I have a 120 amp alternator so I do not use the Ammeter, instead I use a voltmeter which is far more useful to me anyway.

You know Chris you may have hit on something there..if the new alternator puts out more than what the gauge can handle it may have burned up a long time ago..I have an internal alternator and will be putting in a volt gauge this winter..don't like all them amps running thru there!!

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My first parade at Carlisle 2010

I was thinking that I just put in an alternator for the 68 year. however I have discovered that it can be anywhere from 38 amp to 60 amps. depending on AC and other. I will check this out once I get the parts in that I have ordered to put the horn relay in and the new amp gauge. Plus doing some work on the wireing. I really don't understand the fuseable links that corvette put in the wires off the horn relay and starter etc. seems like they just put in a small wire spliced into the 20 guage wire so something would give with an overload.  It wasn't like a fuse itself. So how do I go back and protect these wires if the fuseable links are gone. Maybe just add a circuit breaker or fuse to keep this from happening again. 

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Well to answer the fuse able link question is that it is a wire and not a fuse in a glass tube with a wire thru the middle..the fuse able link looks like and acts like a regular piece of wire untill the amps get to high for what it is rated for then the wire actually melts inside..sometimes you won't even know it..the first thing I do is grab the link and pull on it if it comes apart it's burned up..they are usually at big amp spots like at the starter..it feeds the fuse box..don't use a circuit breaker instead..if you have a short the breaker will catch it then turn it back on again once it cools off..it's like flipping a light switch..not good..you can still get fuse able links..use a quality crimp tool and splice in with the new one..do not solder them..shrink wrap works though..

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My first parade at Carlisle 2010

That is very good info.  Never realized this is how the fuseable link worked, that it was in a glass tube. I guess after 42 years most of this is gone. Where would you find a fuseable link to put  back in the wiring system.  i don't recall seeing any of this in the many catalogs I have.  

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