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Gauge Lights
Thread Starter
Instructor
Joined: Apr 2006
Posts: 206
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From: Ofallon MO
Gauge Lights
Car is a 1981.
I have no gauge lights(tach,speedo, and center clsuter) anymore. I do have tail lights, blinkers etc. As far as I can tell, everything else is functioning correctly. I am blowing the 7.5 amp instrument fuse immediately after turning on the headlights. I was under the hood earlier in the day messing with my timing so it’s possible that I knocked something loose before I noticed it that evening. I don't do much night driving so it could have been that way before. From searching archives, I know it’s most likely a headlight switch or a bad ground somewhere. I was hoping somebody would recognize these symptoms and could steer me in the right direction, since most of the old posts had their taillights out. It never ends…
I have no gauge lights(tach,speedo, and center clsuter) anymore. I do have tail lights, blinkers etc. As far as I can tell, everything else is functioning correctly. I am blowing the 7.5 amp instrument fuse immediately after turning on the headlights. I was under the hood earlier in the day messing with my timing so it’s possible that I knocked something loose before I noticed it that evening. I don't do much night driving so it could have been that way before. From searching archives, I know it’s most likely a headlight switch or a bad ground somewhere. I was hoping somebody would recognize these symptoms and could steer me in the right direction, since most of the old posts had their taillights out. It never ends…
Last edited by BigEarl; Jun 18, 2008 at 07:42 AM. Reason: forgot something
Heel & Toe
Joined: Mar 2007
Posts: 16
Likes: 0
From: Denver Co
here's a site that does replacement bulbs for all bulbs and different colors if u want to change it up its not a kit but a light by light thing u can find kit at corvette central and eklars though hope this helps
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Earl I doubt that your healight switch is your problem because the headlight switch IS the source of power for the 7.5amp fuse.Your problem will be on the load side of the fuse(the bulb side).One of the most common things I find on this dash is the plug on the back of the gauge cluster(above the radio).That cluster has a printed circuit and its pretty fragile.I would pull the cluster out and unplug the plug and see if this will stop the fuse from blowing-if it does then thats the source of your problem.Then check the printed circuit for burns and for the printed circuit being folded over where the plug goes in.
Thread Starter
Instructor
Joined: Apr 2006
Posts: 206
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From: Ofallon MO
Thanks DWncchs
I had an issue (headlights on=gauges stopped working, gauge lights worked, gauges just went to ZERO) with that plug on the back of the cluster about a month ago after installing new radio. So that cluster could affect my tach and speedo lights too? I hate pulling that thing!
I had an issue (headlights on=gauges stopped working, gauge lights worked, gauges just went to ZERO) with that plug on the back of the cluster about a month ago after installing new radio. So that cluster could affect my tach and speedo lights too? I hate pulling that thing!
Last edited by BigEarl; Jun 18, 2008 at 07:31 AM. Reason: spelling
Melting Slicks
Joined: Jul 2005
Posts: 2,740
Likes: 3
From: Aurora Ontario
I just read your original post again. The retrostat going would not blow a fuse. did you ever have a working dimmer function? Turn it fully to the left....does the interior light go on? Does it also blow the fuse?
Jim
Jim
Last edited by jdp6000; Jun 18, 2008 at 08:55 AM.
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Melting Slicks
Joined: Jul 2005
Posts: 2,740
Likes: 3
From: Aurora Ontario
I doubt you hit anyting under the hood. Looking at the book. the 7.5 illuminates the tac/speedo,center cluster,wiper switch,heater switch,shift lever lights and radio light. Power goes to the head light switch first then comes out on the green through the 7.5 and then to all these things through a gray wire (gray/black to the shifter light). Have you done or changed anything that has to do with these things?
Jim
Jim
Thread Starter
Instructor
Joined: Apr 2006
Posts: 206
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From: Ofallon MO
I doubt you hit anyting under the hood. Looking at the book. the 7.5 illuminates the tac/speedo,center cluster,wiper switch,heater switch,shift lever lights and radio light. Power goes to the head light switch first then comes out on the green through the 7.5 and then to all these things through a gray wire (gray/black to the shifter light). Have you done or changed anything that has to do with these things?
Jim
Jim
DWncchs suggested pulling the center cluster and then seeing if I still blow a fuse. Knowing my symptoms, does that sound like a good start?
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
You could pull the sides off the shifter tunnel and check the bulb and socket on the shifter.I doubt you can get your hand behind the speedo and tach to unplug that connector.The other thing is the tiny bulb at the top of center cluster.Then the center cluster.As jdp6000 said its the gray wires.
Melting Slicks
Joined: Jul 2005
Posts: 2,740
Likes: 3
From: Aurora Ontario
The dimmer did work at one time. Other than replacing the radio a month ago, I haven't messed with anything else. I do know for a fact that the lights in gauges worked after the install, because I remember the gauges being lit when the needles fell to zero. The problem then was a bad connection with the plug and the center cluster circuit board.
DWncchs suggested pulling the center cluster and then seeing if I still blow a fuse. Knowing my symptoms, does that sound like a good start?
DWncchs suggested pulling the center cluster and then seeing if I still blow a fuse. Knowing my symptoms, does that sound like a good start?
A bad connection from the plug to the board is logical. It could be it. That plug has to be in just right for evrything to work.
Jim
Thread Starter
Instructor
Joined: Apr 2006
Posts: 206
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From: Ofallon MO
Took center cluster and stereo out. Lights worked.
Hooked up center cluster. Lights worked.
Hooked up stereo, with cluster still attached. Fuse pops.
What would cause stereo to work fine for a month and then all of a sudden start popping fuses?
I thought I had it wired correctly. I used a harness kit, so the only wire I had to "find" was a constant 12V supply. It wasn't plugged into anything, so made sure it was contant and snagged it. I know, I'm a Bubba in the making. Guess the next step is to grab a new constant 12V supply, huh?
Hooked up center cluster. Lights worked.
Hooked up stereo, with cluster still attached. Fuse pops.
What would cause stereo to work fine for a month and then all of a sudden start popping fuses?
I thought I had it wired correctly. I used a harness kit, so the only wire I had to "find" was a constant 12V supply. It wasn't plugged into anything, so made sure it was contant and snagged it. I know, I'm a Bubba in the making. Guess the next step is to grab a new constant 12V supply, huh?
Thread Starter
Instructor
Joined: Apr 2006
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From: Ofallon MO
BTW
The orange/hot wire I used was in the same bundle that went to the old stereo. The bundle had an extra orange and black wire(only 2 wires un-accounted for) that I think had a flat connector on it, so I clipped connector off, took the orange as my hot and left the black wire alone.
Could that black wire which I presume to be a ground wire and is ungrounded be the culprit?
Or should I look for a new hot wire?
The orange/hot wire I used was in the same bundle that went to the old stereo. The bundle had an extra orange and black wire(only 2 wires un-accounted for) that I think had a flat connector on it, so I clipped connector off, took the orange as my hot and left the black wire alone.
Could that black wire which I presume to be a ground wire and is ungrounded be the culprit?
Or should I look for a new hot wire?
Burning Brakes
Joined: Mar 2008
Posts: 1,038
Likes: 39
From: Denver, CO
St. Jude Donor '08-'09-'10
sounds like you have connected a power to ground somewhere in there.. though why it would work for a month................................... ........... maybe you spliced somewhere and just need to make sure wires arent touching? definately in that wiring somewhere
take a volt meter to all the wires and see which is power and which is ground. black is "normally" ground, but you never know with people these days. volt meter and possibly rewire..
and thats me final answer :P
take a volt meter to all the wires and see which is power and which is ground. black is "normally" ground, but you never know with people these days. volt meter and possibly rewire..
and thats me final answer :P
Melting Slicks
Joined: Jul 2005
Posts: 2,740
Likes: 3
From: Aurora Ontario
I don't think the 81 vette had a constant in the factory harness. Thats only needed for stereo's tha have to remember settings. So if you are looking for a constant take it off something else...maybe the lighter.
So you need power from the igntion. Power for the lights off that 7.5 amp fuse.
Probably a source of some sort for a power antenna.
Start from scratch. Except for the speaker wires. find a good ground....the black you mention is probably a ground. find the power source from the ignition. find the gray or gray/black that should be coming from that 7.5 fuse. Your stereo should then have power to play and light up when you pull out the headlight switch...it should also dim.
As for your other question regarding why did it take a month. maybe you had not used the lights in a month? Or maybe you had everything right and two wires near the stereo are touching. I don't think it would be a missing ground.
So you need power from the igntion. Power for the lights off that 7.5 amp fuse.
Probably a source of some sort for a power antenna.
Start from scratch. Except for the speaker wires. find a good ground....the black you mention is probably a ground. find the power source from the ignition. find the gray or gray/black that should be coming from that 7.5 fuse. Your stereo should then have power to play and light up when you pull out the headlight switch...it should also dim.
As for your other question regarding why did it take a month. maybe you had not used the lights in a month? Or maybe you had everything right and two wires near the stereo are touching. I don't think it would be a missing ground.
Melting Slicks
Joined: Jul 2005
Posts: 2,740
Likes: 3
From: Aurora Ontario
You probably know this already. Just because you have power to one part of the stereo does not mean all parts will work. Power source can not be shared. example you need a source for constant, you need ignition source, you need light source (eg 7.5 fuse on gray or gray/black). You can not share sources for these 3 distinct functions.
Jim
Jim