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'80 LUV, 1.8L, gas I4... Standard, 4 on the floor.

Replaced bulbs and still nothing. Tail lights (same bulb as brake lights) turn on with head lights, but no brake lights when I press brake pedal... Stop lamp switch on brake pedal appears to work. (took it out and tested it with test light, powered off battery).

All the other lights on the rear of the truck work.

What am I missing here?? Looked at series 9&10 wiring diagram, but don't see what I'm missing there either... No voltage at the brake pedal switch. Supplied power to the switch and still nothing...

I've also noticed I'm missing my hazard flasher relay, still have turn signal relay. Put a jumper wire on the hazard flasher relay plug, when I hit the hazard switch the turn signals light up, but still no brake lights when I release the switch's button....... Would this be part of it since it's all part of the same circuit? .... I doubt it...

Advice???

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1980 Chevy Luv (1.8L I4, 4-speed) - Should never have bought this pile of crap
1987 Nissan 300ZX (3.0L V6, 5-speed) - Best car I've ever owned

Turn signals and brake lights are a differant circuit. It's a easy system, power from the fuse to the switch in the brake pedal, then power out to the lights with a connection in a multi plug at the bottom of the right side cab firewall.

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Certified pilots, looking down on people since 1903.

How about that switch up under there the one the petal releases when pressed & depresses when not pushing down on the brake petal,...have you checked the adjustment, if that is working correctly ?

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Previously owned 2 Luvs) 75 & 77 Fleet-side
3rd 77 Step fixing up aka The Yellow Submarine to Luv Ms (Sun)Shine=)
98 GMC Gas Guzzler~>The reason 4 my ~>3rdLuvNext2a66MALIBU =)
66 Chevelle The Oldest of all the vehicles I owned

Have you checked for blown #2 fuse? Does the horn work? Same fuse.

Yes, that is the switch I pulled out and tested. I even pulled one out of one of my Nissan parts Z's and still nothing. And yes, it actually fit! Usually if it needs to be adjusted wouldn't the brake lights always be on?



No blown fuses. I recently finished a electrical re-vamp of the wiring harness, ditched stock fuse box and replaced with newer ATC type fuse box. (Along with a lot of new wire to replace frayed/cracked/hacked wiring). Everything that didn't work before works now after all the re-wiring, except for brake lights. :\



Looking at the wiring diagram it looked like those two came off the same fuse. It's kind of hard to read since it breaks into 2 pages right in the middle of the diagram on the right side lol, but I checked and cleaned the multi-plug when I was fixing electrical but maybe I should check it again (this time for voltage) to verify I'm getting power, since there is no voltage at the switch's wires... But even then, I jumped power to the switch and the wires directly from the battery, and still nothing... The only part of the wiring I haven't touched is the part of the harness that goes down the fire wall and under the truck.... Figured I wouldn't have to, but I guess it's not always that easy...

Thanks for all the advice, this has helped me come up with a few ideas!

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1980 Chevy Luv (1.8L I4, 4-speed) - Should never have bought this pile of crap
1987 Nissan 300ZX (3.0L V6, 5-speed) - Best car I've ever owned

Now I'm starting to get pissed...

Checked grounds, they're good.

Traced wires that plug into the brake lamp switch at the brake pedal, they go up the steering column to the hazard switch... If the brake lights aren't parent of the flasher system, why do the wires go to the hazard switch?

Poked around with some jumper wires on the multi-plug right behind the license plate. Passenger side brake light turns on when supplied power, drive side brake light AND turn signal turn on when supplied power, uncovered wiring, everything looks good...

Looked around under the dash and couldn't find any other wires that could possibly go to the brake lamp switch on the brake pedal assembly.

Ran my own wires, directly off the fuse box to the switch then to the brake lights. They work, backwards. When I push in the brake pedal they turn off, when I release the brake pedal they turn... Switched to the other side of the switch, and same thing...

I give up. This truck is about to be scrap.

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1980 Chevy Luv (1.8L I4, 4-speed) - Should never have bought this pile of crap
1987 Nissan 300ZX (3.0L V6, 5-speed) - Best car I've ever owned

Just a quick question, is there or has there been a trailer light adapter in the truck? You know, the ones that take the trucks brake/turn signal and convert them for a trailer.

I just looked at the wiring diagram again. This is a easy circuit. It starts at fuse 2, green wire. This wire also powers a few other items. Check for power at the brake light switch, if there is no power there then get power there. From the switch power goes out a green wire to the connector at the passenger side fire wall, that is pin 2. From there still green to the connector by the license plate, PIN number 4. From there it's still green and goes into the tail light connector on each side.

Does the horn work? Do the flashers work? The number 2 fuse also powers those.

What I would do is power the wire under the dash for the brakes, with a test light check for power at the multi plugs.

Your right that fuse 2 does power the hazards, what I meant was that the brake lights don't go through the hazards like other types of cars.

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Certified pilots, looking down on people since 1903.

The clue here is (the brake light AND tail light come on when power applied to the connector behind the license plate?)
Somehow the tail and brake like circuit is connected together which somewhere that should not be. License plate connector area? Left tail light socket ground problem? If a lighted bulb goes off when you apply power it means you just applied power to the other side of the bulb circuit that should be grounded. I suspect a bad ground is causing all of this.
Hey--stick with this, we got to get this fixed so I can sleep at night.

Sorry guys, I don't mean to talk so mean about my LUV, I'm just too used to working on Z's I lost my patience.

Okay so, looked at the wiring diagram again, the wire for the brake lights is a solid green from power source to switch to lights.

At some point in the past this truck was in the hands of a electrical lunatic (hence why I had to fix about 90% of the wiring in the engine bay...)... This person apparently had disconnected the brake light switch at the brake pedal along with just about every thing else, and when they hooked it back up, they hooked it up to the WRONG wires, the two Green/White wires that come off the hazard switch in the steering column are NOT for the brake lights, hence part of my issue and also explains why I have no power at the switch....



Not that I'm aware of, the part of the wiring that goes under the truck and to the rear lights seems pretty much unmolested. Only thing I noticed was some crumbly dirty connectors.



Yes, I determined this as well with my last look over the diagram, as well as visual inspection of the harness. As I mentioned above, the brake light switch had been hooked to the wrong wires by a previous owner, so making progress...



If I press on the horn, it does not work. If I take the cover off the steering wheel and move the metal disc around enough, the horn works. Turn signal flashers work, hazard flasher relay is missing, if I stick a jump wire in the hazard relay plug and turn on the hazard switch, the turn signal lights illuminate.



Brake lights on both sides come on when power is supplied, turn signal on driver side also comes on... Remember, the tail and brake lights share the same bulb, the turn signal is a separate bulb.



Well you're slightly confused, its the turn signal on the driver side that is turning on with the brake lights when power is supplied to the multi-plug in the license plate area. I did check the ground at the rear of the truck, it is putting out -12 volts, and plan to clean them up to be sure. (There is only one ground in this area?)

So back to what I've been poking around with under the dash... I did some fishing around and found two solid green wires tucked away up under the dash, they seem too short to reach the brake light switch at the brake pedal. 12 volts positive at one of them, so plugged the switch into them and pressed the switch with my thumb.

Same scenario as if I jumped power to the multi-plug in the license plate area. Button pressed down, brake lights on with driver side turn signal on as well. I release the button and the lights go out... Isn't it supposed to be the other way around?

Now that I've made this progress, I suspect it is either a bad ground or frayed wires touching each other. I'll have to uncover the rest of the wiring and see. I think the issue lies somewhere in the wiring AFTER the multi-plug in the license plate area since I have the same issue when jumping power there (so the wiring that runs under the truck should be fine...?)

We'll see what happens, and no worries, this is one of the final issues keeping the truck from being road worthy, so far. Everything else appears to have been repaired with my wiring efforts in the engine bay. I won't give up, might lose my patience, but when that happens I just need to take a break for a little bit!

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1980 Chevy Luv (1.8L I4, 4-speed) - Should never have bought this pile of crap
1987 Nissan 300ZX (3.0L V6, 5-speed) - Best car I've ever owned

Yes the brake light switch is working backwards it seems. What would do that is, the circuit is being fed power from somewhere else. Then when you apply power through the normal switch path it puts 12 volts to the other side (ground) of the bulb and thus zero volts and the light goes off. The fact that the turn signal bulb also lights up bugs me. Wondering if something is still messed up in the steering column turn signal area.
Your right that the stop light switch wires should be green. The other wire/s in that area should be green/white and go the the switch on the throttle pedal--the coaster richer system on the carb. Doing most of this from memory so bear with me.
You might try putting the proper relay into the hazard relay socket to see if that has something to do with all of this stuff.
All that I can think of for now.

Hmm seems legit, I already looked through all the wiring I could get a hold of under the dash and it seems to be okay. (Did fine a few frayed wires and fixed them.) Considering that if I run new wires to the switch and back to the multi-plug in the license plate area, it still does the same, OR if I disconnect the under-truck harness (at multi-plug behind license plate) and jump power directly to the driver side tail light assembly, to the green brake light wire on driver side, it lights up both the turn signal light and brake light.

Considering this and since the rest of the harness is disconnected at this point and power is being supplied from an outside source, I'm going to look through the wiring here (license plate area) and see what I can find and fix as necessary. I'm thinking the 34 year old wiring must've cracked enough somewhere in this area and bare wires are touching.

Of course, if this truck hadn't been in the hands of a electrical lunatic this issues probably wouldn't be happening. When you're cleaning up someone else's electrical mess it is hard to tell what could be causing issues, hence why I decided to stop dicking around and dumped $100 in wire/hardware and re-wired about 75% of the engine bay harness. (The other 25% appeared and now behaves undamaged) It really bugs me when someone does electrical work and twists and tapes the wires or improperly crimps them, but I'm thinking this brake light issue might be a 'natural' cause since there is no evidence of electrical hacking in the rear of the truck (apart from the idiot plugging the brake light switch into the wrong wires....)

Thanks guys, I'll keep you posted!

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1980 Chevy Luv (1.8L I4, 4-speed) - Should never have bought this pile of crap
1987 Nissan 300ZX (3.0L V6, 5-speed) - Best car I've ever owned

Looking at the wireing diagram again, It looks like each tail light assembly has a separate connector and guess what--the #1 and #2 pins are the stop light wire and the turn signal wire, right next to each other. You don't suppose? I would sure look there if you haven't already.

Did some more fishing around, found a couple wires for the head/running lights that were frayed under the dash.

Also noticed that if I disconnect the tail light wire in the license plate area the brake lights do not light up the turn signal light on the driver side. Also noticed that the tail light wire (Green w/ red stripe) is grounding out somewhere. It was still working even with the ground disconnected! Ran a separate temporary ground and the brake lights stopped lighting up the driver side turn signal (for now.) Remember, tail light and brake light share the same bulb!

Did some temporary wiring and this and that, brake pedal switch still works backwards, and I wanted to drive the truck on the roads so bad yesterday, so I hooked the brake lights to a toggle switch so I could still have brake lights while driving Drove her almost 10 miles without issues! A new record, looks like all the work I've done to her the last couple of months is starting to pay off!

Going to have to trace the Green w/Red stripe wire through the harness to find where its grounding out at. Also noticed that the green w/ red stripe wire under the dash is exposed/frayed at the head light switch. Fixed it there but still looks to be grounding out somewhere.

Either way, making progress, going to fix it all right, next chance I get I'm going to start tracing the green w/red stripe wire, it appears to be my issue...

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1980 Chevy Luv (1.8L I4, 4-speed) - Should never have bought this pile of crap
1987 Nissan 300ZX (3.0L V6, 5-speed) - Best car I've ever owned