Recent Posts

71

Electrical / Re: New to forum: Have a 1986 C30 Light issue sat from 2008 untill now!

« Last post by SFR7771 on May 12, 2025, 08:32:07 am »

Did some testing on the rear wires out of the left driver's side block with not much luck, traced wires over tank and lost them, but everything looks solid.

How big of a part does the light switch play in all this wiring issues?

72

Electrical / Re: New to forum: Have a 1986 C30 Light issue sat from 2008 untill now!

« Last post by SFR7771 on May 12, 2025, 07:44:54 am »

Suprizingly, the truck is solid, and all wires are in tacked no signs of and chewed up wires...

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Electrical / Re: New to forum: Have a 1986 C30 Light issue sat from 2008 untill now!

« Last post by bd on May 09, 2025, 01:37:31 pm »

Sitting for that long the problem could be rodent damage.

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Electrical / Re: New to forum: Have a 1986 C30 Light issue sat from 2008 untill now!

« Last post by SFR7771 on May 09, 2025, 12:40:29 pm »

Thanks much appreciated

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Electrical / Re: New to forum: Have a 1986 C30 Light issue sat from 2008 untill now!

« Last post by bd on May 09, 2025, 10:38:08 am »

Verify power on the rear lamp wire harness where it exits the firewall bulkhead connector along the driver (left) side of the connector.  If you have power there the fault is rearward.  Typically, the rear lamp wiring runs through corrugated loom along the left frame rail.  Wire damage/separations can be difficult to locate when hidden inside the loom.  Be patient.

If there is no power through the bulkhead connector, use the diagram of the headlamp switch connections (previously linked) to test power through the pins of the switch.

76

Electrical / Re: New to forum: Have a 1986 C30 Light issue sat from 2008 untill now!

« Last post by SFR7771 on May 09, 2025, 09:52:37 am »

No power at rear on anything but left blinker, no power marker lights. Bulbs are correct...

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Electrical / Re: New to forum: Have a 1986 C30 Light issue sat from 2008 untill now!

« Last post by bd on May 09, 2025, 09:17:26 am »

You didn't mention whether you checked for the correct bulbs and the filament integrity.  Verify the lamp grounds and ensure the bed is grounded to the frame.  Check the wiring harness for melting, abrasion, pinching, and/or severing where it passes over the rear axle near the exhaust pipe; the harness plastic retaining clips fail, allowing the harness to sag or fall away from the frame toward the exhaust.

Regarding the dash lights, see Diagnosing Inoperative Dash Instrument Lighting.

For reference: 1986 GM Wiring Manual

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Electrical / Re: New to forum: Have a 1986 C30 Light issue sat from 2008 untill now!

« Last post by Captkaos on May 09, 2025, 08:33:34 am »

Are you getting power at the rear light sockets? power at the cluster connector?  Power at the rear light harness connector?

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Electrical / New to forum: Have a 1986 C30 Light issue sat from 2008 untill now!

« Last post by SFR7771 on May 09, 2025, 07:43:31 am »

I'm having a lighting issue on my 1986 c30:

    Working: Headlights, front blinkers, cab lights, and the left rear blinker.

    Not working: Tail lights, marker lights, dash lights, and right rear blinker.

    I’ve checked all the fuses, wiring, the fuse on the red wire under the hood, and the wire block.

    I’m also getting no power at the 5-pin trailer connector in the bed.

Is there anything else I should check? I’m trying to get this fixed before driving to the C10 Nationals tomorrow.

80

Fuel Systems and Drivability / Re: new 20 gallon tank

« Last post by Rough75C20 on May 08, 2025, 11:55:19 am »

Perfect. Thank you for the info BD!