Rear lighting issues

[Schurkey]

So... decided to fix the backup lights on our truck...

...I can adjust the switch so that it works in Reverse, that part was surprisingly easy. But as soon as I put it in Park the Switch is forced back to its original position again.

Soo, my question is this.
Will a new switch fix this or is there something else going on here?

WHAT VEHICLE?

IF (big IF) the switch is like the ones in Post #2, check for potential wear to the Trans Position Switch tab.

Pull yours out, inspect for wear. If it's good, put it back in and look elsewhere...but...that switch would be my best guess.

It's supposedly self-adjusting, but I had to move mine over one "click" to get it to work right. Having moved it that one "click" it's held that position ever since. Perhaps the adjuster teeth on yours are worn.

 

[1990Z71Swede]

WHAT VEHICLE?

Sorry, I thought the Signature would give it away

But it is the 1990 K1500 Z71 RCSS

Does it pull right out or is there a tab that needs to be manipulated for it to come off?

I don't want to brake it trying to find out. It´s 30 year old plastic... Sometimes if you just look at things like that funny they explode.

 

[Das Hatt]

Sorry, I thought the Signature would give it away

But it is the 1990 K1500 Z71 RCSS

I believe when viewing the forum on a phone the signature does not appear.

 

[AK49BWL]

The username does tho

 

[palmer6strings]

Sounds like your neutral safety switch is out of adjustment. If adjusting it doesn't fix it, you may need a new one. The little tab on the switch seemed pretty flimsy on the old and new switch I got.

 

[1990Z71Swede]

Update: Most likely the switch needs to be replaced.
But instead of doing the right thing I have Jerry rigged it with a tie wrap...
Works great... for now.

 

[1990Z71Swede]

Tie wrap still going strong.
This is what a tiny $40 24W LED backup light looks like.
The Suburban has one to.
The US backuplights are converted to turning lights, with a yellow bulb. So that Small LED light is the only thing shining in the pics.

 

[HotWheelsBurban]

The username does tho

You have to turn the phone sideways. Then the signature comes up....

 

[Andy Chevy truck]

Is there a trailer-hitch wire harness connector?


I'd be more interested in voltage-drop testing than resistance testing, but at least the wires are not broken and conduct SOME amount of amperage.


They're not supposed to be as bright as the brake lights. Verify the reflectors and lenses are clean. Assure the ground is good.
A 12-volt test light having an old-style incandescent bulb (NOT a new-style test light using LEDs) will give you a better idea of available voltage under load.


That's a puzzler. Apparently the switch works, but is somehow screwed-up in terms of supplying power.

The gear position (backup light) switch in my '88 was worn and defective, but it wasn't working "backwards" from how it should.

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Replacement switch, for comparison. Has an extra circuit that my truck doesn't use.

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Let us know when you figure this out.


1. Verify the bulbs. Some have two filaments, one filament can burn-out so the bulb still lights up "sometimes". If the third brake light works like it should...the brake switch is not the problem.

2. These vehicles have a known, common problem with the circuit board that holds the rear bulbs. Earliest trucks were worst--they used the old-style, push-and-turn bulb sockets. The later (updated) circuit boards use push-in bulbs but they still have problems with corrosion.

3. "Weird" lighting problems are sometimes due to a faulty turn signal switch. Look on your schematic to see which lights have the turn signal switch in common.

I have the same switch but mine looks worse. I bought the same switch as pictured but I can't find how to reinstall it and get it secured. ALSO should The truck be in neutral or park when installing it. I can't tell when I have The Tang lined up. Picture would be great but how to would work. Thanks

 

[Schurkey]

Is there the broken piece of the old switch tang still stuck in the steering column?

I don't remember any problems dropping the new switch into place, except the "automatic, self-adjustment" was a tooth off from perfect. I had to poke the switch over one more notch before it worked right.

Download the service manual set for your vehicle from the links in the sticky-thread section of the Engine forum.