No Dash Lights. Where to start troubleshooting?
11-08-2010, 02:02 PM
#21
Race Director
11-08-2010, 06:49 PM
#22
Race Director
Thread Starter
The instrument lamps have to be grounded or they will not work. They ground by clipping into the rears of the metal cased instruments and by the harness ground on the driver's door hinge post up under the console.
If you keep blowing IP fuses, I'm betting the headlight switch has a bad rheostat.
If you keep blowing IP fuses, I'm betting the headlight switch has a bad rheostat.
11-14-2010, 08:29 PM
#23
Race Director
Thread Starter
Got the steering column out and the left dash pad out today and started looking at the wiring of the lights.
I found 1 small area of one of the gray lights where it had been pinched and wire was exposed and possibly touching the speedo housing. I'm hoping this is going to be the cause of my problems but i still need to get the steering column back in there, plug in some things to be able to test the lights and see if that was my problem...
I only have 1 more of those fuses so if it fails i'll need to order some as the only ones locally i could find come in a variety pack with tons i don't need...
I found 1 small area of one of the gray lights where it had been pinched and wire was exposed and possibly touching the speedo housing. I'm hoping this is going to be the cause of my problems but i still need to get the steering column back in there, plug in some things to be able to test the lights and see if that was my problem...
I only have 1 more of those fuses so if it fails i'll need to order some as the only ones locally i could find come in a variety pack with tons i don't need...
11-28-2010, 04:04 PM
#24
Race Director
Thread Starter
Okay. I worked on the car some today and tried to figure this lighting fiasco out.
I fixed what I thought was the short in one of the gray wires.
I then connected everything half *** back together to see if I could get the lights to work.
I turned the key to on, and no lights came on BUT the fuse didn't blow either. the headlights were working as well as the seatbelt and brights bulbs.
I checked with my multi-meter and I couldn't get a reading across the fuse terminals. I was missing 2 bulbs but i figured that wouldn't stop the others from lighting up...
If I was blowing fuses before then obviously power was going through that fuse. Now with no power through the fuse what did I do wrong? can a bad ground not allow power through that fuse?
I fixed what I thought was the short in one of the gray wires.
I then connected everything half *** back together to see if I could get the lights to work.
I turned the key to on, and no lights came on BUT the fuse didn't blow either. the headlights were working as well as the seatbelt and brights bulbs.
I checked with my multi-meter and I couldn't get a reading across the fuse terminals. I was missing 2 bulbs but i figured that wouldn't stop the others from lighting up...
If I was blowing fuses before then obviously power was going through that fuse. Now with no power through the fuse what did I do wrong? can a bad ground not allow power through that fuse?
11-28-2010, 09:52 PM
#25
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I'm having a similar problem.
Most of the bulbs in my center and tach/speedo clusters had burned out, and most of the gauges stopped working as well. First thing I did was replace the headlight switch, because upon pulling it, I saw burn marks on the plastic. So I put in a new switch, but it had no effect on the dash lights or gauges working.
Next thing I did, I pulled the center cluster and the speedo tach cluster, and replaced all the bulbs, and glued the copper tabs down that had delaminated from the plastic circuit. I also replaced the heat / ac bulb in the top of the center gauge housing, and the bulb at the wiper control. I put everything back together, and now all the gauges work, but NONE of the bulbs come on. I checked the 7.5 amp instrument light fuse, and it looked ok, but slightly corroded. The ground to the drivers door hinge looks ok, and there's another ground on a steering column bolt.
My courtesy lights work fine. Headlights are ok, but I have one burned out taillight.
Any ideas?
Most of the bulbs in my center and tach/speedo clusters had burned out, and most of the gauges stopped working as well. First thing I did was replace the headlight switch, because upon pulling it, I saw burn marks on the plastic. So I put in a new switch, but it had no effect on the dash lights or gauges working.
Next thing I did, I pulled the center cluster and the speedo tach cluster, and replaced all the bulbs, and glued the copper tabs down that had delaminated from the plastic circuit. I also replaced the heat / ac bulb in the top of the center gauge housing, and the bulb at the wiper control. I put everything back together, and now all the gauges work, but NONE of the bulbs come on. I checked the 7.5 amp instrument light fuse, and it looked ok, but slightly corroded. The ground to the drivers door hinge looks ok, and there's another ground on a steering column bolt.
My courtesy lights work fine. Headlights are ok, but I have one burned out taillight.
Any ideas?
11-29-2010, 08:01 AM
#26
Race Director
I'm having a similar problem.
Most of the bulbs in my center and tach/speedo clusters had burned out, and most of the gauges stopped working as well. First thing I did was replace the headlight switch, because upon pulling it, I saw burn marks on the plastic. So I put in a new switch, but it had no effect on the dash lights or gauges working.
Next thing I did, I pulled the center cluster and the speedo tach cluster, and replaced all the bulbs, and glued the copper tabs down that had delaminated from the plastic circuit. I also replaced the heat / ac bulb in the top of the center gauge housing, and the bulb at the wiper control. I put everything back together, and now all the gauges work, but NONE of the bulbs come on. I checked the 7.5 amp instrument light fuse, and it looked ok, but slightly corroded. The ground to the drivers door hinge looks ok, and there's another ground on a steering column bolt.
My courtesy lights work fine. Headlights are ok, but I have one burned out taillight.
Any ideas?
Most of the bulbs in my center and tach/speedo clusters had burned out, and most of the gauges stopped working as well. First thing I did was replace the headlight switch, because upon pulling it, I saw burn marks on the plastic. So I put in a new switch, but it had no effect on the dash lights or gauges working.
Next thing I did, I pulled the center cluster and the speedo tach cluster, and replaced all the bulbs, and glued the copper tabs down that had delaminated from the plastic circuit. I also replaced the heat / ac bulb in the top of the center gauge housing, and the bulb at the wiper control. I put everything back together, and now all the gauges work, but NONE of the bulbs come on. I checked the 7.5 amp instrument light fuse, and it looked ok, but slightly corroded. The ground to the drivers door hinge looks ok, and there's another ground on a steering column bolt.
My courtesy lights work fine. Headlights are ok, but I have one burned out taillight.
Any ideas?
11-30-2010, 12:45 AM
#27
Safety Car
the 68-73 vettes have a cast Iron steering support up under the dash above the steering column, These have very sharp jagged casting Edges and will cut into any wires laying on them, a very common short problem on the C3's.
The headlight Reostate is also a common problem.
then thier is the Gnding scheme which is also very problem-matic.
I Highly suggest beefing up the ground system which a makes its birdcage Gnd.
above the drivers side door hinge, You already beefed up the bird cage and Frame Gnds. right ?
Also the fuse boxes are so aged the fuse clips no longer make good contact with the fuses,
which generate heat making the problem worse.
and finally after removing the fusebox, inside the fusebox,
those connections are usually aged fragile and broken off.
IF you can, I highly suggest reviewing and inspecting/repairing all of these area's on your C3,
do these things, or you will have electrical problems down the road, .... literally.
The headlight Reostate is also a common problem.
then thier is the Gnding scheme which is also very problem-matic.
I Highly suggest beefing up the ground system which a makes its birdcage Gnd.
above the drivers side door hinge, You already beefed up the bird cage and Frame Gnds. right ?
Also the fuse boxes are so aged the fuse clips no longer make good contact with the fuses,
which generate heat making the problem worse.
and finally after removing the fusebox, inside the fusebox,
those connections are usually aged fragile and broken off.
IF you can, I highly suggest reviewing and inspecting/repairing all of these area's on your C3,
do these things, or you will have electrical problems down the road, .... literally.
Last edited by 69Vett; 11-30-2010 at 12:52 AM.
12-01-2010, 05:44 PM
#28
the 68-73 vettes have a cast Iron steering support up under the dash above the steering column, These have very sharp jagged casting Edges and will cut into any wires laying on them, a very common short problem on the C3's.
The headlight Reostate is also a common problem.
then thier is the Gnding scheme which is also very problem-matic.
I Highly suggest beefing up the ground system which a makes its birdcage Gnd.
above the drivers side door hinge, You already beefed up the bird cage and Frame Gnds. right ?
Also the fuse boxes are so aged the fuse clips no longer make good contact with the fuses,
which generate heat making the problem worse.
and finally after removing the fusebox, inside the fusebox,
those connections are usually aged fragile and broken off.
IF you can, I highly suggest reviewing and inspecting/repairing all of these area's on your C3,
do these things, or you will have electrical problems down the road, .... literally.
The headlight Reostate is also a common problem.
then thier is the Gnding scheme which is also very problem-matic.
I Highly suggest beefing up the ground system which a makes its birdcage Gnd.
above the drivers side door hinge, You already beefed up the bird cage and Frame Gnds. right ?
Also the fuse boxes are so aged the fuse clips no longer make good contact with the fuses,
which generate heat making the problem worse.
and finally after removing the fusebox, inside the fusebox,
those connections are usually aged fragile and broken off.
IF you can, I highly suggest reviewing and inspecting/repairing all of these area's on your C3,
do these things, or you will have electrical problems down the road, .... literally.
...... my car had the same problem! come to find out it was a bad ground under the dash.. after i spent a ton on fuses,headlight switch, hours of trouble shooting... Beef up the grounds, and re solder the frail week bulb connections!!! the ground in question for me was a thin piece om metal that jumped the tack to the speedo gauge cluster it was snapped off and i just lost my gauge lighting but every thing else still worked..
12-05-2010, 05:33 PM
#29
Race Director
Thread Starter
I'm getting VERY close to figuring my problem out.
I bypassed the switch and found out that my ground and power wiring in the car works fine, telling me the problem is in the switch.
I opened up the switch and have started testing resistance across the various parts. After seeing how it works i realize that the red wire isn't the only positive wire going into that switch? That in fact there is an orange wire that should be supplying power and that is why my courtesy lights aren't working(with the switch) along with the dash lights.
But my question now is why isn't my orange wire getting power light it should? I'm trying to trace it in my wiring diagram and so far can't figure it out..
I bypassed the switch and found out that my ground and power wiring in the car works fine, telling me the problem is in the switch.
I opened up the switch and have started testing resistance across the various parts. After seeing how it works i realize that the red wire isn't the only positive wire going into that switch? That in fact there is an orange wire that should be supplying power and that is why my courtesy lights aren't working(with the switch) along with the dash lights.
But my question now is why isn't my orange wire getting power light it should? I'm trying to trace it in my wiring diagram and so far can't figure it out..
12-05-2010, 07:32 PM
#31
Race Director
Thread Starter
Fixed
I figured it out! Orange was getting power but the rheostat was broken in one spot. Someone before me had actually tried to fix it by soldering tiny pieces across that just broke again.
My roommate just soldered a small wire gaping the broken segment. Sure I lost some functionality of the rheostat but I plan on putting LED bulbs in when I dye the dash so that'll eliminate the rheostat anyway.
the source of all the problems!
My roommate just soldered a small wire gaping the broken segment. Sure I lost some functionality of the rheostat but I plan on putting LED bulbs in when I dye the dash so that'll eliminate the rheostat anyway.
the source of all the problems!
01-09-2011, 09:52 PM
#32
Instructor
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Here are the problems im having with my 76:
1. My speedo quits working some times
2. When i pull the headlight thingy, my gauges never light up so its a b*tch to drive at night lol
3. My gauges above the stereo, the one that says Door Ajar is always lit up.
4. When im backing up, one of the right rear lights doesnt light up, but when im going forward, it lights up just fine.
Yes im new to all this so i dont know the correct terms quite yet lol
1. My speedo quits working some times
2. When i pull the headlight thingy, my gauges never light up so its a b*tch to drive at night lol
3. My gauges above the stereo, the one that says Door Ajar is always lit up.
4. When im backing up, one of the right rear lights doesnt light up, but when im going forward, it lights up just fine.
Yes im new to all this so i dont know the correct terms quite yet lol
01-10-2011, 12:56 PM
#33
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dash lights
Looking at your fuse block I'll make a stab at what your problem is. Corrosion in the contact area that holds the fuse. I had the same problem. I took a small drimmle tool round stone that would fit the fuse progs and ground it till the rust was removed and it made contact again. Mine have worked since. I had it happen again with the AC fuse did the same thing remove the rust. Hope this helps
01-10-2011, 09:20 PM
#34
Safety Car
04-09-2014, 09:28 PM
#35
1st Gear
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I worked on not dash lights for several weeks and at the end I found where the last owner had installed tow new spekers in the rear of the 77 Corvette and he pulled the 12 volts off the cigarette lighter, and for some reason he connected it by way of a multi connector bar on it he had a gray and a black groung wire in the same port. And this was the reason for blowing the 5A fuse problem solved.
