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#1
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67 GTO light problem
67 GTO NO LIGHTS
Headlights work No parking lights/no 4 way flasher/no taillights/map reading lights dont work Open door and courtesy lights under dash work Checked fuses........OK Light switch has 12 volts on red and blue wires, no voltage on purple/brown, or white Any help would be appreciated, thanks |
#2
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Normal Configuration:
Red - 12 volt Battery feed from fuse panel Lt Blue - 12 volts from HDLT switch to dimmer switch to HDLTs White - Ground wire for dome or map lights, should show 10-12 volts with doors closed (12 volts feeding through dome/map light bulb). 0 volts when door is open or HDLT switch turned all the way to the left Purple - 12 volts from HDLT switch to front parking lights Brown - 12 volt Battery power from Tail light fuse to HDLT sw to tail lights QUESTIONS 1. Map lights are over the doors and replace the dome light and consists of a combination Map/Interior Light. Is this what you have? Is it the actual map light that doesn't work or the Interior light section? 2. Do the Brake lights work? TAIL LIGHTS / PARKING LTS My first thought is the headlight switch is bad. If the fuses are good as you say then the only other possibility is the switch. (Normally) MAP LIGHTS Check bulbs Check for Power inside the map light sockets. (Orange wire) IF NO POWER If you have map lights over the doors the wire connection is usually over the drivers side rear wheel well inside the trunk. See if you have an Orange & White plug from the rear twilight harness there. It should connect to the Orange/White map light harness. It has the same fuse as the under dash courtesy lights (Normally) Check rear harness plug under drivers side carpet if the everything else checks out. FOUR WAY FLASHERS The four way flashers are fed from 12 V Battery power through the flasher on the fuse panel to the turn signal switch.. Easy check is to replace the flasher can first then the brown wire to the signal switch. Power will fluctuate from 0 to 12 volts. Connector is on the lower steering column. Note: I say normally since this is the normal factory configuration. Who knows what previous owners have done in the last 50 some years
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Ed 1968 GTO (Thanks Mom) 2006 Silverado 2007 Cadillac SRX 2015 Chevy Express |
#3
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EDIT
EDIT Green looks like dash light feed to fuse box (my bad) With all that's mentioned, power to the fuse box might have got lost. Like a master splice coming apart. Or rot behind the box. Need to probe both ends of fuses, with a test light, to see if anything is there. That's the fuses that should be hot 24/7. Clay Last edited by "QUICK-SILVER"; 10-05-2020 at 06:19 PM. Reason: correction |
#4
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The factory schematic doesn't show the color of the wire from the fuse box to the headlight switch for the tail lights. Since I don't have a 67 I'm just going by the manual and assumed (wrongly perhaps) that it was brown. The wire from the headlight switch to the tail lights is brown.
The owner stated he had 12 volts at the headlight switch for the red and blue wires which would coincide with the headlights working. He did not mention a green wire in his post. Hopefully he drops in to verify.
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Ed 1968 GTO (Thanks Mom) 2006 Silverado 2007 Cadillac SRX 2015 Chevy Express |
#5
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67 GTO light problem
Great information , thanks!! There is a green wire also which I failed to check, will do so once I get home today.
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#6
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67 GTO light problem
Checked the light switch again today
Red wire - 12 volts Lt Blue wire - 12 volts White wire - 0 volts - 10 -12 volts with door switch depressed . Floor courtesy lights work , roof lights and map reading lights do not work. Purple wire - 0 volts Brown wire - 0 volts Green wire - 0 volts Brown w white tracer wire - 0 volts All these voltages were done with light switch on , vehicle off, Have ordered a light switch. See no broken wires or blown fuses in and around fuse box. |
#7
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Got to test for power on both ends of fuses. No power in the fuse box for tail lights and dome... Headlight switch still wont turn things on. And do probe fuse ends and clips that hold them. Don't trust a fuse because it looks good.
Clay |
#8
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When you test the headlights do
you pull the switch out all the way? Try pulling it out halfway and see if the parking light come on. Agree with Clay regarding the taillights and the green wire. Check the fuse on both sides with a test light or meter. Looking at the schematic again it I see the courtesy lights and the map/reading lights operate off different fuses. Check the dome light fuse for voltage on both sides of the fuse. The dome light fuse also operates the brake lights. So check those too. Since all these fuses have the same source (Red wire which is spliced inside the harness to feed the fuse box and light switch from the battery) it's as Clay said, The splice inside the dash harness or the connection in the fuse box is probably bad.
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Ed 1968 GTO (Thanks Mom) 2006 Silverado 2007 Cadillac SRX 2015 Chevy Express |
#9
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67 GTO light problem
Thanks for all your information Ed, still waiting on switch from Ames, then I will check what you have suggested. I believe I checked for parking light with the switch halfway out.
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#10
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Quote:
Switch should have two hot wires. One for headlights (red) and one for park/tail (brown w/white). Double check both ends of fuses and retaining clips with a test light. Looks good don't count on fuses. The diagram I have is a bit generic. But looks like three fuses in a row should be hot at all times. Your description says one is hot and two are not. Clay |
#11
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67 Headlight circuits
__________________
John Wallace - johnta1 Pontiac Power RULES !!! www.wallaceracing.com Winner of Top Class at Pontiac Nationals, 2004 Cordova Winner of Quick 16 At Ames 2004 Pontiac Tripower Nats KRE's MR-1 - 1st 5 second Pontiac block ever! "Every man has a right to his own opinion, but no man has a right to be wrong in his facts." "People demand freedom of speech to make up for the freedom of thought which they avoid." – Socrates |
#12
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67 GTO light problem
Problem with lights resolved , replaced switch and 20 amp fuses, of which 1 of them checked good with ohm meter !
Still dont have map lights or dash lights, will check further later this week. Ed , you said there is a fuse in the orange/white harness going to map lights? Or did I read that wrong, hope its not up in headliner area. Thanks for the quick replies and helpful information, very much appreciated |
#13
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The green wire from headlight switch to fuse box is dash light power when headlight switch is turned 'ON'. It goes through the middle fuse in the fuse box. Then it's gray wires out to the bulbs.
Did you try working the rheostat to bright/dim the dash lights? Dome light fuse is on the opposite end of the fuse box from the hazard flasher. That fuse does power dome, hazard and stop lights. The in-line fuse that got mentioned goes to a brake switch for cruise control. Clay |
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