68 C10 parking lights, turn signals, and brake lights do not work - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Pzary3233 · 10-04-2014, 09:29 PM

Working on this old truck to get her road legal and am having a very hard time with the lights to get them working.

I have the color coded diagrams from elsewhere on the forum and have tried to trace as much wiring as I can.

I have replaced the light switch and have a turn signal switch on order.

I have zero parking lights front or rear, no turn signals front or rear, and no brake lights either. Also, the dash lights don't work. Fuses are good.

At the brake light switch there is no power from the white wire coming from the turn signal switch.

At the light switch (new replacement) there is no power from any wires except for the red and light blue (headlights) wires.

At the turn signal switch I do get power on the purple wire but that's all.

At this point I think I have narrowed it down to the turn signal switch but I am not confident of my diagnosis. Is there any way to trouble shoot the switch with an ohm meter?

Anything I am missing?

_Ogre · 10-05-2014, 01:28 PM

one thing nice about working on gm vehicles is the wire colors haven't change (much) over the years
there should be 3 hot wires into your turn switch, if you have hazard blinkers
white wire is hot from the brake switch, not from the turn switch. this should feed 12v+ to the switch when the brake is depressed.
purple is 12v+ to the turn signal switch through the turn blinker. if your switch, wire and lights are good you should have turn indicators
if your truck has hazard lights there will also be a brown 12v+ from the hazard blinker to the switch

parking lights and tail lights have no connection to turn/hazard lights other than the same fixture and dual element bulb.
red is power to your headlight switch, blue goes to the hi/lo beam switch and brown for parking/marker lights

pic from vettevet in this thread. also wiring diagram for headlights and turn
http://67-72chevytrucks.com/vboard/s...d.php?t=593546

Pzary3233 · 10-06-2014, 11:30 AM

Light switch:
I do not have power coming off of the light switch to any other wire except for the Lt. Blue wire when the lights are on. In the parking light position no wires are hot other then the red feed wire. The Orange wire does not get power when the light is turned to the dome light position. The Dk Green wire for the dash lights also does not get power when the light switch is turned on (Either Parking Lights or Headlights). When the switch is off, what SHOULD be hot? the Red wire only? When the switch is turned all the way on the Brown, Dk Green, and Lt Blue wires should ALL be hot. This is a new light switch, that is acting the same as the old one. Did I get a bad switch?

Turn Signal Switch:
I was confused thinking that the parking lights also ran through the turn signal switch... Just the brake lights so that they can be interrupted for a turn signal. I only have power going to the switch on the purple wire. there is no other power going TO the switch.
Brake Light Switch:
So you're saying that the Orange wire feeds power to the brake light switch which then feeds power to the turn signal switch. This orange wire has no power. Fuse is good. It looks like this orange wire travels from the fuse block to the dome light connector where it splits then to the brake light switch.

Wiring:
My wiring from the junction block at the firewall to the front parking lights has checked out good. Same goes for the wiring to the rear of the truck, from the firewall back it is in good shape. Grounds, I have cleaned the ground connections and added ground straps from the bed to the frame, from the engine to the frame and from the frame to the body. The truck should be well grounded.

_Ogre · 10-06-2014, 06:01 PM

light switch: after studying the wire diagram....
i have a feeling that the orange wire may feed power to the head light switch for your parking lights so read/fix brake switch first
you say it is acting the same as the old switch the orange wire power may be the only problem with the old switch

turn switch: with power to the purple wire your turn indicator lights should work
your truck has that silly half round column connector unplug it and jumper the purple wire to:
lt blue will tell you the lf light/wire is good
dk blue will tell you the rf light/wire is good
yellow will tell you the lr light/wire is good
green will tell you the rr light/wire is good
all these lights should also flash because the purple wire is from the turn flasher
if all your lights work then your turn switch needs work

brake switch: according to the wiring diagram that vettevet posted (where the heck is vettevet?)
it looks like you have a separate fuse for brake/dome in the panel
i am not sure why the orange wire also goes to the headlight switch; this may be the power in to the switch for the parking lights
pull the fuse and check for power at the fuse panel then trace power out from there
if the fuse is good and you have no power then a connection or wire is bad
getting power to the orange wire may fix a plethora of your problem

**VetteVet** · 10-06-2014, 11:12 PM

Well You are doing a pretty good job on this one so I've been watching to see what happens after he gets the new turn signal switch. I quoted your post so I could confirm what you are thinking based on the diagram below.

Originally Posted by _Ogre View Post
light switch: after studying the wire diagram....
i have a feeling that the orange wire may feed power to the head light switch for your parking lights so read/fix brake switch first

This is the headlight and fuse panel diagram for his model, the one above is for the 67 and newer models.

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The orange wire does indeed feed the headlight switch for the parking, dome, and dash lights.Look closely and you can see it comes from the fuse panel to the switch for parking and dome light. The lights on the left are the dash lights. They are powered by the green wire which runs back to the fuse panel and then to the dash lights. The orange wire tees with another orange wire that goes to the brake light switch. The dome light is turned on with the switch knob by grounding the black wire on the headlight switch. All these items are related to the orange wire that feeds the headlight switch.

you say it is acting the same as the old switch the orange wire power may be the only problem with the old switch. Looks like it

turn switch: with power to the purple wire your turn indicator lights should work.

Yes as long as the TS switch is good. Power on the purple wire with the key on and the switch in the up position the dark green wire should have power, down position the yellow wire should have power..Light blue and dark blue are for the front signals as stated below.

your truck has that silly half round column connector unplug it and jumper the purple wire to:

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lt blue will tell you the lf light/wire is good
dk blue will tell you the rf light/wire is good
yellow will tell you the lr light/wire is good
green will tell you the rr light/wire is good
all these lights should also flash because the purple wire is from the turn flasher
if all your lights work then your turn switch needs work

Another method is to use a multimeter and check for continuity on the wires in the switch. This involves the column side of the harness where the above checks the truck side of the harness as per Ogre.

Multimeter set on ohms scale. TS handel in neutral.
Red lead on white wire from brake switch and black lead on dark green then yellow. Zero ohms reading on both, then check the cutout on the brake lights by moving the TS lever up on the right check and down on the left check and the meter should read infinity. Brake wiring in TS is good.

Right turn- Red lead on purple, black lead on dark green, switch lever in up.
Zero ohms.

Left turn- Red lead on purple, black lead on Yellow, switch lever down.
Zero ohms.

brake switch: according to the wiring diagram that vettevet posted (where the heck is vettevet?)
it looks like you have a separate fuse for brake/dome in the panel
i am not sure why the orange wire also goes to the headlight switch; this may be the power in to the switch for the parking lights
pull the fuse and check for power at the fuse panel then trace power out from there
if the fuse is good and you have no power then a connection or wire is bad
getting power to the orange wire may fix a plethora of your problem

Exactly Right. VV

Pzary3233 · 10-07-2014, 08:47 AM

Thank you guys for the help I'm not armed with a bit more information to get this worked out. still waiting on the turn signal switch, it's currently back ordered...

VetteVet - I am actually working on a 68 for this project, rather then a 60-66 truck.

I'll attack the truck again tonight with my multimeter and test light. I am not very good with wiring diagrams so again thanks for the help!

I'll test the turn signal switch as well as follow the orange wire and see where that gets me.

_Ogre · 10-07-2014, 12:03 PM

about time vettevet chimed in

so... get power to the orange wire, get the marker lights working and power in/out of the brake switch
personally i'd check wires and connectors before changing out the ts switch, you may just have corrosion in the column connector

i'm more of a 55-59 and aftermarket harness guy, but the basic circuits haven't changed much
i remember trying to understand the ts switch in the days before the internet, back when i had to drive my dinosaur to the library

**VetteVet** · 10-08-2014, 12:13 AM

Quote:

Originally Posted by Pzary3233

Thank you guys for the help I'm not armed with a bit more information to get this worked out. still waiting on the turn signal switch, it's currently back ordered...

VetteVet - I am actually working on a 68 for this project, rather then a 60-66 truck.

I'll attack the truck again tonight with my multimeter and test light. I am not very good with wiring diagrams so again thanks for the help!

I'll test the turn signal switch as well as follow the orange wire and see where that gets me.

Sorry I missed that, I just looked at the 63 in your signature and thought it was the year. I usually don't goof up like that but the good thing is, they are pretty much the same. Good luck on the trouble shooting. VV

Pzary3233 · 02-02-2015, 10:09 AM

All right, finally got this all figured out.

First I pulled the fuse box to make sure that everything was ok on the back side of the block.

Issue #1 - The orange wires coming from the block had a large amount of rust scale on the back of the box. Cleaned it all up and then the orange wire had power! Volia, had parking lights and a dome light! The orange power wire is the key to the lights!

Issue #2 - Turn Signal switch - I pulled the steering wheel off and the switch pretty much fell apart as I was pulling it out. I was afraid of doing that job but ended up rebuilding the column as well.

Now everything works as it should. One parking light had a ground issue but that has since been resolved.

Something that helped me out a lot was printing out the wiring diagram for the entire truck and laminating it. Then Highlighting the wires I was looking for - that was I can see where it goes and where I needed to troubleshoot.

_Ogre · 02-02-2015, 01:58 PM

thanks for the update and glad everything is working

Pzary3233 · 02-02-2015, 01:59 PM

Yeah, I hate it when threads get left without the issue resolved.

I couldn't have done the electrical with you you and VetVette's help!

*randy500* · 05-11-2020, 05:18 PM

Ttt for Nathan Rosser

10-06-2014, 11:30 AM	#3
Pzary3233 Registered User Join Date: Apr 2012 Location: Memphis, TN Posts: 65	Re: 68 C10 parking lights, turn signals, and brake lights do not work Light switch: I do not have power coming off of the light switch to any other wire except for the Lt. Blue wire when the lights are on. In the parking light position no wires are hot other then the red feed wire. The Orange wire does not get power when the light is turned to the dome light position. The Dk Green wire for the dash lights also does not get power when the light switch is turned on (Either Parking Lights or Headlights). When the switch is off, what SHOULD be hot? the Red wire only? When the switch is turned all the way on the Brown, Dk Green, and Lt Blue wires should ALL be hot. This is a new light switch, that is acting the same as the old one. Did I get a bad switch? Turn Signal Switch: I was confused thinking that the parking lights also ran through the turn signal switch... Just the brake lights so that they can be interrupted for a turn signal. I only have power going to the switch on the purple wire. there is no other power going TO the switch. Brake Light Switch: So you're saying that the Orange wire feeds power to the brake light switch which then feeds power to the turn signal switch. This orange wire has no power. Fuse is good. It looks like this orange wire travels from the fuse block to the dome light connector where it splits then to the brake light switch. Wiring: My wiring from the junction block at the firewall to the front parking lights has checked out good. Same goes for the wiring to the rear of the truck, from the firewall back it is in good shape. Grounds, I have cleaned the ground connections and added ground straps from the bed to the frame, from the engine to the frame and from the frame to the body. The truck should be well grounded. __________________ '55 3200 283 4 speed '68 Pontiac Firebird Poncho powered with a 6 speed

10-06-2014, 06:01 PM	#4
_Ogre Registered User Join Date: Jan 2012 Location: Motown Posts: 7,666	Re: 68 C10 parking lights, turn signals, and brake lights do not work light switch: after studying the wire diagram.... i have a feeling that the orange wire may feed power to the head light switch for your parking lights so read/fix brake switch first you say it is acting the same as the old switch the orange wire power may be the only problem with the old switch turn switch: with power to the purple wire your turn indicator lights should work your truck has that silly half round column connector unplug it and jumper the purple wire to: lt blue will tell you the lf light/wire is good dk blue will tell you the rf light/wire is good yellow will tell you the lr light/wire is good green will tell you the rr light/wire is good all these lights should also flash because the purple wire is from the turn flasher if all your lights work then your turn switch needs work brake switch: according to the wiring diagram that vettevet posted (where the heck is vettevet?) it looks like you have a separate fuse for brake/dome in the panel i am not sure why the orange wire also goes to the headlight switch; this may be the power in to the switch for the parking lights pull the fuse and check for power at the fuse panel then trace power out from there if the fuse is good and you have no power then a connection or wire is bad getting power to the orange wire may fix a plethora of your problem __________________ cool, an ogre smiley Ogre's 58 Truk build how to put your truck year and build thread into your signature shop air compressor timer

10-06-2014, 11:12 PM	#5
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,703	Re: 68 C10 parking lights, turn signals, and brake lights do not work Well You are doing a pretty good job on this one so I've been watching to see what happens after he gets the new turn signal switch. I quoted your post so I could confirm what you are thinking based on the diagram below. Originally Posted by _Ogre View Post light switch: after studying the wire diagram.... i have a feeling that the orange wire may feed power to the head light switch for your parking lights so read/fix brake switch first This is the headlight and fuse panel diagram for his model, the one above is for the 67 and newer models. The orange wire does indeed feed the headlight switch for the parking, dome, and dash lights.Look closely and you can see it comes from the fuse panel to the switch for parking and dome light. The lights on the left are the dash lights. They are powered by the green wire which runs back to the fuse panel and then to the dash lights. The orange wire tees with another orange wire that goes to the brake light switch. The dome light is turned on with the switch knob by grounding the black wire on the headlight switch. All these items are related to the orange wire that feeds the headlight switch. you say it is acting the same as the old switch the orange wire power may be the only problem with the old switch. Looks like it turn switch: with power to the purple wire your turn indicator lights should work. Yes as long as the TS switch is good. Power on the purple wire with the key on and the switch in the up position the dark green wire should have power, down position the yellow wire should have power..Light blue and dark blue are for the front signals as stated below. your truck has that silly half round column connector unplug it and jumper the purple wire to: lt blue will tell you the lf light/wire is good dk blue will tell you the rf light/wire is good yellow will tell you the lr light/wire is good green will tell you the rr light/wire is good all these lights should also flash because the purple wire is from the turn flasher if all your lights work then your turn switch needs work Another method is to use a multimeter and check for continuity on the wires in the switch. This involves the column side of the harness where the above checks the truck side of the harness as per Ogre. Multimeter set on ohms scale. TS handel in neutral. Red lead on white wire from brake switch and black lead on dark green then yellow. Zero ohms reading on both, then check the cutout on the brake lights by moving the TS lever up on the right check and down on the left check and the meter should read infinity. Brake wiring in TS is good. Right turn- Red lead on purple, black lead on dark green, switch lever in up. Zero ohms. Left turn- Red lead on purple, black lead on Yellow, switch lever down. Zero ohms. brake switch: according to the wiring diagram that vettevet posted (where the heck is vettevet?) it looks like you have a separate fuse for brake/dome in the panel i am not sure why the orange wire also goes to the headlight switch; this may be the power in to the switch for the parking lights pull the fuse and check for power at the fuse panel then trace power out from there if the fuse is good and you have no power then a connection or wire is bad getting power to the orange wire may fix a plethora of your problem Exactly Right. VV __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative.

10-07-2014, 08:47 AM	#6
Pzary3233 Registered User Join Date: Apr 2012 Location: Memphis, TN Posts: 65	Re: 68 C10 parking lights, turn signals, and brake lights do not work Thank you guys for the help I'm not armed with a bit more information to get this worked out. still waiting on the turn signal switch, it's currently back ordered... VetteVet - I am actually working on a 68 for this project, rather then a 60-66 truck. I'll attack the truck again tonight with my multimeter and test light. I am not very good with wiring diagrams so again thanks for the help! I'll test the turn signal switch as well as follow the orange wire and see where that gets me. __________________ '55 3200 283 4 speed '68 Pontiac Firebird Poncho powered with a 6 speed

10-07-2014, 12:03 PM	#7
_Ogre Registered User Join Date: Jan 2012 Location: Motown Posts: 7,666	Re: 68 C10 parking lights, turn signals, and brake lights do not work about time vettevet chimed in so... get power to the orange wire, get the marker lights working and power in/out of the brake switch personally i'd check wires and connectors before changing out the ts switch, you may just have corrosion in the column connector i'm more of a 55-59 and aftermarket harness guy, but the basic circuits haven't changed much i remember trying to understand the ts switch in the days before the internet, back when i had to drive my dinosaur to the library __________________ cool, an ogre smiley Ogre's 58 Truk build how to put your truck year and build thread into your signature shop air compressor timer

10-04-2014, 09:29 PM	#1
Pzary3233 Registered User Join Date: Apr 2012 Location: Memphis, TN Posts: 65	68 C10 parking lights, turn signals, and brake lights do not work Working on this old truck to get her road legal and am having a very hard time with the lights to get them working. I have the color coded diagrams from elsewhere on the forum and have tried to trace as much wiring as I can. I have replaced the light switch and have a turn signal switch on order. I have zero parking lights front or rear, no turn signals front or rear, and no brake lights either. Also, the dash lights don't work. Fuses are good. At the brake light switch there is no power from the white wire coming from the turn signal switch. At the light switch (new replacement) there is no power from any wires except for the red and light blue (headlights) wires. At the turn signal switch I do get power on the purple wire but that's all. At this point I think I have narrowed it down to the turn signal switch but I am not confident of my diagnosis. Is there any way to trouble shoot the switch with an ohm meter? Anything I am missing? __________________ '55 3200 283 4 speed '68 Pontiac Firebird Poncho powered with a 6 speed

10-05-2014, 01:28 PM	#2
_Ogre Registered User Join Date: Jan 2012 Location: Motown Posts: 7,666	Re: 68 C10 parking lights, turn signals, and brake lights do not work one thing nice about working on gm vehicles is the wire colors haven't change (much) over the years there should be 3 hot wires into your turn switch, if you have hazard blinkers white wire is hot from the brake switch, not from the turn switch. this should feed 12v+ to the switch when the brake is depressed. purple is 12v+ to the turn signal switch through the turn blinker. if your switch, wire and lights are good you should have turn indicators if your truck has hazard lights there will also be a brown 12v+ from the hazard blinker to the switch parking lights and tail lights have no connection to turn/hazard lights other than the same fixture and dual element bulb. red is power to your headlight switch, blue goes to the hi/lo beam switch and brown for parking/marker lights pic from vettevet in this thread. also wiring diagram for headlights and turn http://67-72chevytrucks.com/vboard/s...d.php?t=593546 __________________ cool, an ogre smiley Ogre's 58 Truk build how to put your truck year and build thread into your signature shop air compressor timer

02-02-2015, 10:09 AM	#9
Pzary3233 Registered User Join Date: Apr 2012 Location: Memphis, TN Posts: 65	Re: 68 C10 parking lights, turn signals, and brake lights do not work All right, finally got this all figured out. First I pulled the fuse box to make sure that everything was ok on the back side of the block. Issue #1 - The orange wires coming from the block had a large amount of rust scale on the back of the box. Cleaned it all up and then the orange wire had power! Volia, had parking lights and a dome light! The orange power wire is the key to the lights! Issue #2 - Turn Signal switch - I pulled the steering wheel off and the switch pretty much fell apart as I was pulling it out. I was afraid of doing that job but ended up rebuilding the column as well. Now everything works as it should. One parking light had a ground issue but that has since been resolved. Something that helped me out a lot was printing out the wiring diagram for the entire truck and laminating it. Then Highlighting the wires I was looking for - that was I can see where it goes and where I needed to troubleshoot. __________________ '55 3200 283 4 speed '68 Pontiac Firebird Poncho powered with a 6 speed

02-02-2015, 01:58 PM	#10
_Ogre Registered User Join Date: Jan 2012 Location: Motown Posts: 7,666	Re: 68 C10 parking lights, turn signals, and brake lights do not work thanks for the update and glad everything is working __________________ cool, an ogre smiley Ogre's 58 Truk build how to put your truck year and build thread into your signature shop air compressor timer

02-02-2015, 01:59 PM	#11
Pzary3233 Registered User Join Date: Apr 2012 Location: Memphis, TN Posts: 65	Re: 68 C10 parking lights, turn signals, and brake lights do not work Yeah, I hate it when threads get left without the issue resolved. I couldn't have done the electrical with you you and VetVette's help! __________________ '55 3200 283 4 speed '68 Pontiac Firebird Poncho powered with a 6 speed

05-11-2020, 05:18 PM	#12
randy500 Account Suspended Join Date: Jul 2016 Location: Tacoma, WA Posts: 6,873	Re: 68 C10 parking lights, turn signals, and brake lights do not work Ttt for Nathan Rosser



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