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Discussion Starter · #1 ·
Hey guys! New firebird owner and new member here with a rather strange issue. I will attach a video of the problem, but I think an explanation is due as well. Since discovering this issue I've learned that lights issues are common to firebirds, but the issues with mine seem to be completely unique. After all the research I've done, I have yet to find anyone else with a problem similar to mine.

Since I bought this car a couple of weeks ago, the rear left lights have not worked properly in anyway. WIth the running lights and headlights off, the left turn signal, brake lights, and hazards work somewhat normally except for one thing, the wrong filaments are lighting up. From what I can make out, the bulbs all have to 2 filaments, which the socket can activate separately. Filament A and filament B. FIlament A, on the right lights (the working ones), is dimmer, and turns on when the running lights are on. Filament B, is somewhat brighter, and lights up with the activation of brake lights, turn signals, or hazard lights. On the left (the broken side), with the running lights off, filament B does not light up for any reason but instead filament A takes its place and lights up for turn signals and brake lights. However, with the running lights on, the left turn signal turns OFF filament A (again, the wrong filament for brake lights/turn signals) instead of activating them like it like it does with running lights off. The brake lights do the same thing, as do the hazards which most clearly show the issue in the video. You'll notice the timing on all the lights (especially hazards) is off too but I suspect that is a symptom of whatever is causing the larger issue, and can be remedied with the same repair.

Here is the video a recorded on the issue:

I activate the lights in this order from start to finish: running lights off: left turn signal, right turn signal, hazards, brake lights. Running lights on: left turn signal, right turn signal, hazards, brake lights.

Any and all responses are appreciated! I'm desperate to fix this issue myself as money isn't something I have a whole lot of at this time. Hiring a mechanic to fix it would prevent me from doing a lot of other things to my firebird that I would really like to do, at least for the time being. Thanks for reading!
 

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First off, welcome to the forum.

Next go to 4th gen tech section and download the 95 service manual. It will have full wiring diagrams. Your first task is to see if a previous owner monkeyed with the wiring for the left back lights.

Have you checked the bulbs in the left tail light to see if both filaments are intact?

You could have bad bulb sockets on the left tail light assembly.

And check that grounds for left side are a good tight connection, and are clean corrosion free.
 

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Thank you! And thanks for the hasty reply, as far as the sockets and bulbs go all seems well. I swapped bulbs around with new ones and known-working ones from the right side lights; no changes. The sockets themselves seemed rather clean. If i recall correctly they were also supplying power properly when i tested each contact individually with my tester (before my tester broke anyway). I downloaded the wiring diagrams but I am having trouble making sense of them. Could you tell me where I can find the grounds?

EDIT: Did you mean the ground connection on the sockets themselves? I checked those and they seemed okay, but I'll see if i can check them again
 

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If you downloaded the 95 service manual, the wiring diagrams have 19 pages devoted to grounds. Starting on page 8A-12-0 Then starting on page 8A-201-0 are the component views section which will show you where various grounds are located.

The sockets for the bulbs are grounded by a black wire that is connected to car body. Component views section will show you where these are.

If the ring terminal is corroded or the body contact area is dirty, you won't have a good ground. And if ground connection is loose, bad ground also.
 

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Ramblin' Wreck
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I have no doubt you are missing the ground(s) for both left side dual-filament bulbs. The symptoms you described and we can see in the video match that fault exactly. Either both left side 2-filament bulbs are not making contact with the grounds in the sockets, or the ground for those sockets is missing between the socket and the cable splice point. It is also possible that the two sockets were replaced and wired incorrectly. Do they look fairly new? Since it is rare that a splice could go bad, I suspect incorrect socket re-wiring. Double check the socket-to-bulb match to see that the filament common pin in each bulb goes to the ground pin in the socket. Try running a separate ground wire from a body ground in the rear to to one of the problem sockets on the left and see if that fixes that bulb.

The reason the left side low current filaments (tail lights) go out is because the voltage at the other pin (brake/turn/DRL) in the bulb is opposing it without the ground. I.e. 12v at each end = no current.

The reason you don't see filament B light up for any reason is because even though the voltage is there, the current level is very low due to the filament A (higher resistance) being in series with it because of the missing ground.
 
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Discussion Starter · #6 ·
Thanks for all the replies guys, you both really seem to know what you're doing! I, however, do not. The wiring diagrams are not only a pain to find in the 4100 page manual without a physical copy (i have one in the mail), but I am not able to gather from them the information that I need. I understand this is likely too much to ask, but if somebody would be interested in skyping with me to explain what I need to be looking for, it would save me some headaches. For now though, I will continue searching for the problem until I find something of significance.

I actually did find that the one of the wires on both bad sockets was loose, and pulling it out somewhat made the lights much brighter, but didnt change anything else. it is the more recessed of the 3
 

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Update: I think i found it. one of the connections to both of the sockets is too loose. I can mess with it enough to get it to work but as soon as I replace the light assembly it stops working, i will order some new ones or attempt to repair the sockets but i think that's the problem mostly dealt with. only thing that i still cant get right is the timing of the hazards but ill save that for later, might just need a new flasher (i had to replace the one for the signals already)

I found the exact socket but a new one is 40 dollars!

These are 8 dollars, will they work the same way? its hard to tell but both amazon and rockauto say they are compatible: https://www.rockauto.com/en/moreinfo.php?pk=4673892&cc=1251975&jsn=492&jsn=492
 

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I gave you the exact page numbers from the manual for the ground circuits and component views, so you would know where the body grounds are.

I will now include the page number that exterior lights diagrams start on. 8A-110-0 And for good measure the page headlight diagrams begin.

8A-100-0.

Fuse box details start on 8A-11-0. Power distribution starts on page 8A-10-0

As you will note, all the things you need are in section 8A of the manual. Scroll through the manual until you find section 8A. At the beginning of section 8A is a short course in reading wiring diagram symbols.

If you wish to work on any car from the 1980's on, you need to know how to read wiring diagrams and perform trouble shooting methods using a digital multi meter. And this is just the start.

Your public library probably has books on basic automotive electrics and electronics. You need to learn this stuff.

Sorry I have no camara on my computer. Nor do I wish to have one.
 

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Ramblin' Wreck
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These are 8 dollars, will they work the same way? its hard to tell but both amazon and rockauto say they are compatible: https://www.rockauto.com/en/moreinfo.php?pk=4673892&cc=1251975&jsn=492&jsn=492
No, I don't think that one will fit into the housing. Look at the 3 tabs that have to fit into the housing. They are evenly spaced and I believe the ones in the car are not evenly spaced, more like the socket in my attached photo. You would have to, at least, cut off one of the tabs and then it may be too loose in the housing. That looks like the backup light socket. See if the tabs on your backup light socket looks like that one. Also see if your sockets look like the tabs on the LS49 which is supposed to be the replacement. It is the 2nd photo (ACDelco socket) attached

There is a lot of confusion regarding the sockets on these cars but you should be able to find some that are reasonably priced. I found some for mine, but I have a 98 and that takes a different bulb. Of course, you could always switch to the newer bulbs (3157/4157)

You didn't answer my question about whether the sockets look new or not.
 

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Sorry Gary I didn't see that, they do not look very new. They are quite dirty on the outside but still fairly clean on this inside at least. I will keep poking around for more reasonably priced proper sockets, 40 dollars is extremely steep for something something like this. Is there a way I can repair them myself?

Robert I understand that I have more to learn, and I will but at this point I just need a running car. The rest of the restoration and improvement will come when I have more money to sink into it.

https://www.rockauto.com/en/moreinfo.php?pk=4673592&cc=1305425&jsn=589&jsn=589&jsn=589 These look like they fit, I'm fine with buying new bulbs if it means i dont have to spend 80 dollars on a couple of sockets. Do you think that will work?
 

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https://www.rockauto.com/en/moreinfo.php?pk=4673592&cc=1305425&jsn=589&jsn=589&jsn=589These look like they fit, I'm fine with buying new bulbs if it means i dont have to spend 80 dollars on a couple of sockets. Do you think that will work?
As long as they fit the housing, they should work. Keep in mind that a lot of these are made in China and they try to cover many different cars with the same compromised design, so the wire colors may not be the same and the tabs may not match. Carefully examine your tabs and compare them with what you see in the photos. That isn't always easy to do and I have been mistaken about that myself and had to "modify" them later. i got some from Autozone for about $8 (all wires were black) that fit fine but I am not sure about your car. That way you pay no shipping at the local store. Dorman 85881 was the part number and it was found by specifying a 96 Malibu tail light socket, if I remember correctly. Even giving the A-zone clerk the part number wasn't enough to find it in their stock. Maybe they have fixed that now. At least you can try it and return it if it doesn't fit:

http://www.autozone.com/electrical-and-lighting/brake-lamp-socket/dorman-directional-indicator-bulb-socket/18625_0_0/
 

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I just replaced all of my sockets in the rear. Posted that somewhere. I had the symptoms listed here and then some. Not only did the sockets fix all of my issues, my fuel guage works again. The reason I'm saying something is because of "the tabs". I had to file a tab off of a couple sockets to fit. My holes were "2 tab" and the sockets were 3. Autozone sold me all of them.

Also, make sure ALL the lights are correct. I had a couple mis-matched bulbs. Installing the correct bulb number (wattage) made a huge difference.

For the record, during the day, everything worked. At night, the right blinker would not blink, brake lights got dim on one side and bright on the other. Eventually, one bank just went completely dead when pressing the brake pedal. Last symptom to develop was the "you left your headlights on" chime when I stepped on brake pedal with ignition off or key out of ignition.

New sockets resolved it all. New sockets come with way more wire than you need. ...or so you'll think. I had to cut back 6-12" on every socket except the corner lamps. The copper wire was *black*. Cut back to good copper.

My sockets did look like the ones GaryDoug posted in the "tab" image, however, they were not like that before I installed the "honeycomb" tail lights which leaked and became fishbowls. Before those honeycombs, I had clean looking sockets and still had tail-light issues. looked like at one point previous owner tried to resolve the issue by running screws into the back of the connector to push the contacts against the bulb more.

All said and done, only took an hour to carefully cut back each wire, cut the necessary tabs from new connectors, wire, solder, and shrink wrap the connections. Amazing results! ...and as I said, added bonus, my fuel guage began working! glad I didn't replace the pump/sending unit when I planned on it.

The electrical is 20+ years old. Consider just replacing ALL the connectors. It couldn't hurt.
 

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Discussion Starter · #13 ·
I will be looking into lots of "because it will probably break soon" replacements once I have more money to sink into it. Right now though, I pulled apart and repaired the sockets myself. All is well except that that hazards now don't work at all but I'm not very concerned about that, might just be a broken flasher (I had to replace the turn signal one already). However everytime I fix something on this car I find some other problem, like a red black and orange wire under the dashboard that someone felt like cutting for reasons unbeknownst to me. But I digress, thanks for the help everyone, I'm sure I will need it again soon! I think I'll be a permanent member to this forum
 
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