need electrical help
Thread Starter
Drifting
Joined: Aug 2007
Posts: 1,721
Likes: 67
From: Redding ca.
need electrical help
Finally got my 66 on street, but none of the gauges work except the ammeter. Interior lights work--all the time, and the left rear turn signal works but not brake light. Thats it. Have all new Lectic Ltd harnesses. Engine runs and starts well. Do not have head and parking and back-up lights hooked up yet. From earier post, some have said the turn signal switch is one of the culprits, but what else? I'm not good with electrics but have a VOM meter. Any and all help would be appreciated. Thanks, Chuck
Tech Contributor
Joined: May 2005
Posts: 15,576
Likes: 118
From: Conroe Texas
I don't know what the source of your problem is, but I'd start by ensuring the BLACK ground wire with the female connector is plugged into the ground lug on the top of the cluster, over the Tach.
Then I'd confirm the DARK BROWN wire with the female connector is hooked up to a Capacitor that I believe is bolted to the back of the cluster under the Oil gauge.
It is easy to get the 2 swapped, and when you do, your cluster has to find a ground path through alternative means, such as the oil line (unless you have an aftermarket plastic oil line in place)
Then I'd confirm the DARK BROWN wire with the female connector is hooked up to a Capacitor that I believe is bolted to the back of the cluster under the Oil gauge.
It is easy to get the 2 swapped, and when you do, your cluster has to find a ground path through alternative means, such as the oil line (unless you have an aftermarket plastic oil line in place)
Thread Starter
Drifting
Joined: Aug 2007
Posts: 1,721
Likes: 67
From: Redding ca.
jeff,thanks so far
jeff, I checked that the black is in fact on the ground at the top of the cluster. I do not have the capacitor for the dark brown wire. Thought it was for radio interference originally, since i'm using modern digital radio its not necessary? Ground must be good since the blue wire to the left turn dash indicator light flashes Temp guage is hooked up onto sender at engine, the wires to the sender at the tank are hooked up and all the dash lights work. Tach is electronic now and not hooked up anyway. btw, can i use the capasitor brown wire as a ground for other things such as the radio? Any more help would be appreciated. chuck
Tech Contributor
Joined: May 2005
Posts: 15,576
Likes: 118
From: Conroe Texas
When you say the interior lights work all the time - do you mean the courtesy lights, or the ones on the dash board?
It sounds like most of your gauges are not getting any power then, since your instrument cluster lights are clearly getting ground (they wouldn't work other wise).
Have you double checked the integrity of the connections at the firewall/fuse box?
Hopefully others will chime in to help.
Advanced
Joined: Jan 2008
Posts: 88
Likes: 0
From: Niceville Florida
Chuck, I used the Lectric Limited harnesses and the only issue that I ran into was the ammeter hookup. In fact I just finished sorting that out this weekend.
I would agree with 62Jeff on checking all of the connections again. I know when I hooked up the two engine side harnesses at the firewall they were extremely tight and took a bit to seat. Might want to pull the off and reseat and see if that helps.
I taped off the brown wire for the radio capacitor. I like you have an aftermarket radio and did not need it, but you don't need a hot wire under the dash to short out.
I would agree with 62Jeff on checking all of the connections again. I know when I hooked up the two engine side harnesses at the firewall they were extremely tight and took a bit to seat. Might want to pull the off and reseat and see if that helps.
I taped off the brown wire for the radio capacitor. I like you have an aftermarket radio and did not need it, but you don't need a hot wire under the dash to short out.
Thread Starter
Drifting
Joined: Aug 2007
Posts: 1,721
Likes: 67
From: Redding ca.
jeff, the courtesy lights stay on all the time with nothing but the battery hooked up. That one is sorta wierd since at first only the pass. side lit up and would go ff when door is closed, but it came back on and stayed on. The driver side didn't come on at first so I bought a new switch but before I could put it in, it too came on and now stays on. Had to pull bulbs so as to not drain battery. Also, checked firewall connectors and the clips? are intact.
Pro
Joined: Jan 2001
Posts: 526
Likes: 34
From: Mt. Laurel NJ
6t6t7
I would work on these problems one at a time.
The courtesy lights are simple. Power is applied to one side of the lamp and the other side is grounded through the door switches or the headlight switch. Is the headlight switch turned all the way counter clockwise? If not, check each door switch to make sure it opens the ground circuit when the door is closed.
The temperature gauge has power supplied from the top fuse in the fuse panel on one terminal and the temperature sensor connected to the other terminal. The temp. sensor provides the ground. Check the fuse first. Then pull the connector off the gauge and check to see if there is battery voltage on one of the terminals. Then check the resistance from the other terminal to ground. Can't remember exactly what it should be with a cold engine, less than 200 ohms I think.
CUL Jim
I would work on these problems one at a time.
The courtesy lights are simple. Power is applied to one side of the lamp and the other side is grounded through the door switches or the headlight switch. Is the headlight switch turned all the way counter clockwise? If not, check each door switch to make sure it opens the ground circuit when the door is closed.
The temperature gauge has power supplied from the top fuse in the fuse panel on one terminal and the temperature sensor connected to the other terminal. The temp. sensor provides the ground. Check the fuse first. Then pull the connector off the gauge and check to see if there is battery voltage on one of the terminals. Then check the resistance from the other terminal to ground. Can't remember exactly what it should be with a cold engine, less than 200 ohms I think.
CUL Jim
Instructor
Joined: May 2006
Posts: 211
Likes: 0
From: N. Tustin Ca
Chuck. with no instument lights and dome light on all the time, it
sounds like the ignition switch and light switch may be wired wrong,
ie... wires to the wrong switch check your wiring diagram in the manual
again.
sounds like the ignition switch and light switch may be wired wrong,
ie... wires to the wrong switch check your wiring diagram in the manual
again.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Tech Contributor
Joined: May 2005
Posts: 15,576
Likes: 118
From: Conroe Texas
The temperature gauge has power supplied from the top fuse in the fuse panel on one terminal and the temperature sensor connected to the other terminal. The temp. sensor provides the ground. Check the fuse first. Then pull the connector off the gauge and check to see if there is battery voltage on one of the terminals. Then check the resistance from the other terminal to ground. Can't remember exactly what it should be with a cold engine, less than 200 ohms I think.
CUL Jim
CUL Jim
The temp gauge, fuel gauge, and parking brake flashing light are all on the same fuse. A failure in any one of those components can blow the fuse and render all of them dead. On my 65, the optional backup lights are also on that fuse.
After replacing all of my wiring with the Lectric Limited harness, everything worked fine for one or two tanks of gas and then I lost all of the above items. By disconnecting the temp gauge wire from the sensor, the backup light connector, and the hot wire at the fuel sending unit, I was able to replace a blown fuse and then start connecting components until the fuse blew again - confirming that my fuel sending unit had shorted out inside of the tank.
As for the courtesy lights, I'm leaning towards either a bad passenger light switch, or maybe you turned the headlight **** all the way to the "courtesy light" position as Jim notes.
Burning Brakes
Joined: Jan 2005
Posts: 768
Likes: 0
From: Leavenworth Washington
Advice to take these one at a time is right on. The "one thing fixes all" is tempting in electrics but rarely the case. I would pull both courtesy light switches and disconnect them from the circuit. Make sure the wire from the switch to the light isn't touching ground and see if the lights come on. If they do, they're getting a ground from somewhere else. You can track that with your VOM. The 12V feed to the gauges comes from the ignition switch. Check to see if the 12V to the #1 fuse switches on and off when the ignition switch switches on and off (ACC position won't switch this fuse)
Thread Starter
Drifting
Joined: Aug 2007
Posts: 1,721
Likes: 67
From: Redding ca.
replys
thanks all so far;
jimc-switch was all the way counterclockwise, but now courtesy lights don't work in any position,door open or closed nor does maually pushing the swithes do anything. The top fuse is good.
mayordaly-instrument lights do work, but not courtesy lights now.
geeks65-I will check top fuse for on off.
cray- I have large plastic coated schematic that came with the harness. thanks anyway.
Looks like ive got a lot more checking to do--will get back with any results!
Chuck
jimc-switch was all the way counterclockwise, but now courtesy lights don't work in any position,door open or closed nor does maually pushing the swithes do anything. The top fuse is good.
mayordaly-instrument lights do work, but not courtesy lights now.
geeks65-I will check top fuse for on off.
cray- I have large plastic coated schematic that came with the harness. thanks anyway.
Looks like ive got a lot more checking to do--will get back with any results!
Chuck
Thread Starter
Drifting
Joined: Aug 2007
Posts: 1,721
Likes: 67
From: Redding ca.
progress
I don't know how, but instruments now work. I checked top fuse and it does go on and off via the key. The only thing I found that might havr been a problem was the headlight up-down switch was hanging loose and was apparently in contact with the big circuit breaker(?) on the kick panel wall. Courtesy lights now will not work at all. The brake lights do not work, but I have not checked the switch yet..........because I installed the passenger seat and took my long suffering wife for her first ride. She loved it and so did I. Tomorrow is another day. I shall return!!!!!
