Parking light grounding

[Joyridin]

My 68 C10 seems to have a bit of a ground issue I believe. When I turn on the parking lights, both turn signal lights light up (not full brightness), and the turn signals stop working. When the parking lights are off, the turn signals seem to work as normal.

Somebody chopped a bit of the wiring for the front parking lights years ago. I assume that one of the wires going to the light is for the parking lights, one is for the turn signal, and the housing is the ground? Is this correct? If not, does anybody know where the actual ground wire for the front parking/turn signals are located?

Thanks.

[71CHEVYSHORTBED402]

Info. for my 71. Seems yours would be the same without side lamps. Won't swear to the colors though.

Brown, 18 AWG
Front Marker Lamps, and Park Lamps. Brown is for the front side marker lamps, and the park lamps.

The front marker lamp connectors have an 18 AWG black ground wire.

Light blue, 20 AWG
LH front signal. Light blue is for the LH park lamp’s turn signal. Reference the instrument panel connector.

Park lamps are grounded by their housings.

Dark blue, 20 AWG
RH front signal. Dark blue is for the RH park lamp’s turn signal.

[PbFut]

The grounding circuit is simple, but has areas that can fail. There are leads in the harness to ground the Radiator support. Black wire with eye hoops. One under the battery, the other is same position on driver side. It is not a bad Idea to run a jump wire from this same attachment point direct to the battery. The ground for the parking/turn signal lamps is via the housing attachment to the radiator support. You need to be sure that paint or rust inhibitor or corrosion is not in the way of a good connection. Bulb to socket, socket to housing via those metal retainer tabs around the socket, and finally the metal bracket that bolts to housing to the radiator support. All those contact points are potentails for a broken circuit.

[Rust_never_sleeps]

There are threads on here about turning your side marker lights into blinkers(not sure what 68 was like rolling off the assembly line)
If the wiring has been touched, it's possible someone did that mod....or tried

[Joyridin]

Originally Posted by 71CHEVYSHORTBED402

Info. for my 71. Seems yours would be the same without side lamps. Won't swear to the colors though.

Brown, 18 AWG
Front Marker Lamps, and Park Lamps. Brown is for the front side marker lamps, and the park lamps.

The front marker lamp connectors have an 18 AWG black ground wire.

Light blue, 20 AWG
LH front signal. Light blue is for the LH park lamp’s turn signal. Reference the instrument panel connector.

Park lamps are grounded by their housings.

Dark blue, 20 AWG
RH front signal. Dark blue is for the RH park lamp’s turn signal.

Thank you!

[Joyridin]

Originally Posted by PbFut

The grounding circuit is simple, but has areas that can fail. There are leads in the harness to ground the Radiator support. Black wire with eye hoops. One under the battery, the other is same position on driver side. It is not a bad Idea to run a jump wire from this same attachment point direct to the battery. The ground for the parking/turn signal lamps is via the housing attachment to the radiator support. You need to be sure that paint or rust inhibitor or corrosion is not in the way of a good connection. Bulb to socket, socket to housing via those metal retainer tabs around the socket, and finally the metal bracket that bolts to housing to the radiator support. All those contact points are potentails for a broken circuit.

Good idea on running from the core support to battery. I will do that just to be sure.

Thank you!

[Joyridin]

I found the issue and not what I expected. When somebody added the 2nd set of parking lamps, they somehow switched the wiring. The turn signal was going to the parking light side of the bulb, and the parking light was going to the turn signal side of the bulb.

I switched the wiring and everything is fine now.

[Sunchild714]

Originally Posted by Joyridin

I found the issue and not what I expected. When somebody added the 2nd set of parking lamps, they somehow switched the wiring. The turn signal was going to the parking light side of the bulb, and the parking light was going to the turn signal side of the bulb.

I switched the wiring and everything is fine now.

Success! Nice, easy fix.

[71CHEVYSHORTBED402]

Originally Posted by Joyridin

I found the issue and not what I expected. When somebody added the 2nd set of parking lamps, they somehow switched the wiring. The turn signal was going to the parking light side of the bulb, and the parking light was going to the turn signal side of the bulb.

I switched the wiring and everything is fine now.

They had a 50/50 chance Nice you found it.