Weird problem with hazard lights

[ohaggdahl]

Hi guys,
I have a mystery with my hazard lights that I’m curious to see if anyone’s got any advice about..
1990 Suburban

They stopped working all of a sudden. Here’s where I’m at:
-hazards don’t work at all
-turn signals work as usual
-fuse is not blown
-relay/flasher is fine for both turn signal and hazards (1990 have them separate)
-button on steering column works as intended
-all other lights work 100%
-hazard wiring has constant 12v as intended, at the flasher

I would think it’s the switch in the column.. the wiring inside, that’s gone bad, but here’s what I don’t get.

As intended, the hazards never flash when you have the brake pedal pushed, and what’s happening now is that even though the hazards don’t work, when the hazard button is pushed in, and I put my foot on the brake pedal, all the lights that would be flashing, light up solid.
Meaning, that leads me to believe at least the truck knows the hazard button is pushed, because otherwise that wouldn’t happen. That’s with all power off, key out, as intended.

Any thoughts?
Does the wiring harness from column split off to both main fuse box for lights etc, but separately to the “convenience center” or whatever it’s called, where the hazard flasher is?

Hope this makes some sense…

Thanks guys!

 

[YakkoWarner]

So if I understand the description correctly, when you turn on the hazards, nothing happens. But if you press the brake while the hazard switch is ON, then all the lights (front turn signal/dash turn signal/rear brake-turn) come on and stay on for as long as you hold the pedal? With the hazard switch off, do the brake lights operate correctly?

Does anything interesting happen if you turn on the hazard switch and then (with key on) use the left or right turn signal? If you turn on the parking lights does anything different happen?

Bad grounds can cause all sorts of unique unexpected effects with lighting, and different combinations of lights being switched on and off can allow current flow to go in unintended directions. It sounds like when you press the brake with the hazard switch on, voltage is feeding back from the rear dual-function filiments through the rest of the hazard circuit, causing the rest of that circuit to energize. I think I'd start by checking the grounds at the rear lamps.

 

[Ricko1966]

If the brake lights work normally it's not a rear ground problem. Brake,Turn and Hazard all three use the same wire,bulb and ground at each rear lamp. It sounds like when he steps on the brake it backfeeds the switch with power from the brake lights lighting up all hazard bulbs with brake lamp voltage. I'd checkbfor power to the hazard switch.

 

[ohaggdahl]

Hey guys - I’m back at it with this.
I’ve now gotten into the switch inside the steering column, cleaned everything, and everything looks good.

Still no hazards… and again, everything else works as it should.

Does someone have a wiring diagram for the hazards?

There are two wires; brown and orange going into the hazard relay.
Should orange be a constant hot, and brown pulse from switch when engaged?

 

[75gmck25]

Orange wire should be a constant hot that does not require the ignition to be on.

Are the turn signal and hazard flashers the same? If they are, try switching them around and see if that helps. Flashers do go bad.

If it’s an original mechanical flasher it’s a really simple device with a bimetallic strip inside that heats up and clicks back and forth. However, your truck is new enough that it might have an electronic flasher.

 

[MrMarty51]

Bad hazard flasher

 

[gmbellew]

Did you swap the 2 flashers to see if it makes a difference? Wondering how you tested the flasher…

 

[TotalyHucked]

I think we need some more clarity here OP. So you're saying when you push in the hazard button, nothing happens at all? Then step on the brake pedal and the rear lights light up solid? Did you actually test the relays to make sure they're good?

On my '85, my hazard relay was dead when I bought the truck. When I try to activate the hazards, everything just lights up and stays solid, never blinks. Push the brake pedal, no change. I swapped with another truck at work and they blink just fine. I've never bothered to actually buy a new relay, so I haven't had hazards for the past 5 years lol. But now my blinker relay has died so I guess I'll suck it up and replace both

 

[ohaggdahl]

Thanks so much guys!!

And yes, I’ve checked the relays.
The truck has separate turn signal and hazard relays (although identical relay type) and both relays work in the turn signal location, but neither do anything in the hazard location.

They do not light up solid in my case.
All other light functions operate normal / as intended.

Hazard fuse good, relay good, and seemingly, switch in column good.

I’ve also checked all bulbs on the entire truck.

So next step is I have to start checking wires and try to trace this.

Thanks!

 

[TotalyHucked]

"As intended, the hazards never flash when you have the brake pedal pushed, and what’s happening now is that even though the hazards don’t work, when the hazard button is pushed in, and I put my foot on the brake pedal, all the lights that would be flashing, light up solid."

I think this line in your original post is what's confusing. So you're saying you push in the hazard button and just nothing at all happens, right? All other lights function properly, you just don't have anything at all happen with the hazards. I think the part about pushing the brake pedal is what's confusing.

 

[Jgonick]

the brake it backfeeds the switch with power from the brake lights lighting up all hazard bulbs with brake lamp voltage.

^^This^^ The hazard lights are not receiving current from the brown wire which means a short in the brown wire or a bad brown wire connection or a bad hazard switch not supplying the current. -- (assuming fuse and flasher relay are good).

There are two wires; brown and orange going into the hazard relay
Should orange be a constant hot, and brown pulse from switch when engaged?

Yes.

 

[ohaggdahl]

Thanks guys!

Just to be clear. On all older GM vehicles, if the hazards are ON, and you put your foot on the brake pedal, then the hazards/lights stop flashing, and just are lit solid until you let go of the brakes and they continue to flash. This is factory.

What I’m saying is, currently, the hazards do nothing. No flashing at all. But when I put my foot on the brake pedal, they do light up solid, as intended. And that is even with power off, since the hazards are being supplied a hot feed at all times. All of that is as intended, except they are NOT flashing when I let go of the brakes.

The only conclusion I can come to is that the hazard switch IS doing something, because otherwise the lights would not light up solid with power off when foot is on brake pedal.

I guess I need to try to find a wiring diagram and follow both brown (pulse from switch ) and orange (constant hot) the entire way.

I don’t understand how the switch would be broken if the truck “registers” that it’s pressed in since it then functions as intended when the brake pedal is pressed.

To me that would mean the switch is sending the signal from the column, and down somewhere, but not all the way to the relay.
I need to troubleshoot that with a voltmeter. But I don’t know the entire wiring of where it goes from the switch.

Unbelievably frustrating!!

Appreciate any insight…

 

[PrairieDrifter]

I'd put money on it's the switch.

 

[Ricko1966]

Thanks guys!

Just to be clear. On all older GM vehicles, if the hazards are ON, and you put your foot on the brake pedal, then the hazards/lights stop flashing, and just are lit solid until you let go of the brakes and they continue to flash. This is factory.

What I’m saying is, currently, the hazards do nothing. No flashing at all. But when I put my foot on the brake pedal, they do light up solid, as intended. And that is even with power off, since the hazards are being supplied a hot feed at all times. All of that is as intended, except they are NOT flashing when I let go of the brakes.

The only conclusion I can come to is that the hazard switch IS doing something, because otherwise the lights would not light up solid with power off when foot is on brake pedal.

I guess I need to try to find a wiring diagram and follow both brown (pulse from switch ) and orange (constant hot) the entire way.

I don’t understand how the switch would be broken if the truck “registers” that it’s pressed in since it then functions as intended when the brake pedal is pressed.

To me that would mean the switch is sending the signal from the column, and down somewhere, but not all the way to the relay.
I need to troubleshoot that with a voltmeter. But I don’t know the entire wiring of where it goes from the switch.

Unbelievably frustrating!!

Appreciate any insight…

The power is coming from the brake lights and backfeeding all the lights on the output side of the switch!!!!! Why?? Because they are all tied together there when the switch is closed !!!!!!! You need to check
everything in the input side of the switch. If all the lights come on,with the hazard switch on and the brakes depressed.,I know everything is connected on the output side of the switch. If you have everything correct on the input side of the switch it is the switch itself.

 

[Jgonick]

Let me try to explain- With Hazard switch on the switch is getting power from brn wire and and the hazard lights flash. When you step on the brake it also gets power from the white wire- (no flasher relay) the hazard lights stay on. That is normal function---

Just to be clear. On all older GM vehicles, if the hazards are ON, and you put your foot on the brake pedal, then the hazards/lights stop flashing, and just are lit solid until you let go of the brakes and they continue to flash. This is factory.

YES, exactly..


Your situation- pressing brakes with hazards on, all lights work- that means all the grounds and wires and bulbs are fine in that circuit. When you release brakes- hazards do not flash- that means for some reason it is not getting power from the brown wire. - anything that is dealing with the brown wire could be the problem-(example- bad relay, bad fuse, bad connection, broke wire, even bad switch if it is not allowing contact with brn wire, etc...)


Just a FYI- the turn signal switch functions differently and it switches power from the purple wire to the left or right sides taking the brake (white) power wire out of the circuit.


See attachment- maybe that will help you see what is going on.