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Help.. Tail lights are lighting the front parking lamps??
I am new to this form and just purchased a 1978 Corvette. I have a feeling I will be using this Form a lot. LOL The first issue is with the break lights and turn signals.
1> First issue...I have absolutely no turn signals at all. When I picked up the car 2 weeks ago the left signal worked fine but the right one just came on solid. Now nothing at all.
2> Secondly, when the running and headlights are on all front running lights, side markers, tail lights and headlights work just fine (except the driver front side marker which I just found had a burnt out bulb which I am replacing tomorrow) so all appears to be working fine.
3> The issues start when I depress the break;
1st lets look at what happens when the lights are OFF;
When I depress the break pedal several things happen 1> The inside dash turn signal indicators (both right and left) comes on solid. 2>The right rear BREAK LIGHT Does not light up but the left rear does. 3>The 2 front facing running lights light up (not any of the side markers).
2nd Lets look at what happens when the lights are ON: When I depress the break pedal 1> the, inside dash turn signal indicators (both right and left) comes on solid. 2>The right rear tail light goes out and the break light does NOT come on. 3>The left rear goes from tail light to break light just as it should 4>The front facing running lights light up BRIGHTER than they are as running lights.
I just replaced the two rear tail/break bulbs tonight. One was somewhat rusted but the inside of both sockets looked pretty good.
It feels like something in the right rear tail/break light is back feeding only the two front facing running lights as the front and rear SIDE markets do not light up when the headlights are off and I press the break. That said that doesn't support why i have no turn signals at all lights on or lights off.
You might want to start with a new directional signal flasher.
See number 2.
Make sure all the bulbs are good. (#1157)
Sometimes the sockets corrode on the inside and loose their ground.
Attach a wire to a good ground and touch the other end of the wire to the brass part on the socket and see if the bulb now blinks.
Post back your results and we can proceed from there.
You might want to start with a new directional signal flasher.
See number 2.
Make sure all the bulbs are good. (#1157)
Sometimes the sockets corrode on the inside and loose their ground.
Attach a wire to a good ground and touch the other end of the wire to the brass part on the socket and see if the bulb now blinks.
Post back your results and we can proceed from there.
I will do that. Thank you for your help! I check all bulbs to assure they are grounded, replace the bulb I know is bad and the Directional signal flasher and reply back/
In a '78 the turn signal flasher is NOT in the location shown in that illustration! It is in the bottom-right corner of the fuse box. While the flasher may be malfunctioning it won't cause most of the symptoms you describe.
The very first thing I suggest you check is that the proper light bubs are installed in the proper places. Improper bulbs (often single filament instead of dual filament) can cause the exact sort of "feedback" problems you see.
The front lights turn/park lamps (below the headlights) are supposed to be dual filament amber bulbs trade #1157A. Check for the proper trade number written on the bulb and also be certain that you see three distinct conductors (one dead center) at the back of the bulb.
The turn/stop/park lights in the rear (the outboard ones) should have clear dual filament bulbs trade #1157
You have all the symptoms of bad grounds at the sockets, either by corrosion or loss of connection. All the sockets have to be grounded for the lights to work correctly. Any ground you lose can cause current to pass through filaments where it shouldn't and not pass where it should. As said by others, your first two attacks should be correct bulbs, rotated correctly and making contact, and the bulb base must be grounded to the socket and the socket to a good ground. All the bulbs, any one can cause problems with others, they all use the same ground and 12v.
I once owned a 78 that had multiple light issues and the problem was inside the socket connector where the black wire plugs into it. I'll draw an arrow on the picture already provided above.
There is a ground for the rear harness that includes all the lights and the fuel level sender. Check that out, sorry idk the exact location
Good suggestion as lots of lighting quirkiness is due to a poor ground.
The location for that ground in on the frame rail on the drivers side about equidistant with the end of the muffler. There are two ground wires on it as mentioned above. Lay on your back and look up- you seriously cant miss it.
This ground wire causes a lot of problems as it is exposed to road and wet. It is just good PM to take it apart and get after it with a wire brush. I did mine two weeks ago-- 10 minutes tops and most of that time was spend looking for the correct size socket (10mm on an 82)
Last edited by billschroeder5842; 08-04-2016 at 12:46 PM.
Good suggestion as lots of lighting quirkiness is due to a poor ground.
The location for that ground in on the frame rail on the drivers side about equidistant with the end of the muffler. There are two ground wires on it as mentioned above. Lay on your back and look up- you seriously cant miss it.
This ground wire causes a lot of problems as it is exposed to road and wet. It is just good PM to take it apart and get after it with a wire brush. I did mine two weeks ago-- 10 minutes tops and most of that time was spend looking for the correct size socket (10mm on an 82)
Thank you..Last night I saw some type of grounding bar right next to that exhaust on the drivers side. Its pretty rusted over and there is was a long (8" or so) breaded wire that was hanging loose off that bar. It looked like it might have somehow ground the telescopic antenna motor (just a wild guess because it was just long enough to be connect to that grounding bar and the antenna motor). The antenna replacement is down the road because the antenna is broken off. Anyway's I'm not sure if that breaded wire came off from something else but there were other wires still attached to that bar...I just didn't get a chance to trace them yet as it was getting late. i will try to clean this up and report back. Thanks again.
You might want to start with a new directional signal flasher.
See number 2.
Make sure all the bulbs are good. (#1157)
Sometimes the sockets corrode on the inside and loose their ground.
Attach a wire to a good ground and touch the other end of the wire to the brass part on the socket and see if the bulb now blinks.
Post back your results and we can proceed from there.
Quick update: i found the directional signal flasher and then opened the glove box to review the manual. In there i found another signal flasher laying in the glove box...Bad sign as someone appears to have tried this before. Again I have only had the car two weeks So today i bought a new signal flasher along with some new replacement bulbs and fuses. I think I'm going to start with cleaning and checking all grounds before i replace the Signal flasher but all items will be replaced. I will report back once i get the grounds cleaned and checked and all new bulbs and signal flasher installed!
Thanks!
In a '78 the turn signal flasher is NOT in the location shown in that illustration! It is in the bottom-right corner of the fuse box. While the flasher may be malfunctioning it won't cause most of the symptoms you describe.
The very first thing I suggest you check is that the proper light bubs are installed in the proper places. Improper bulbs (often single filament instead of dual filament) can cause the exact sort of "feedback" problems you see.
The front lights turn/park lamps (below the headlights) are supposed to be dual filament amber bulbs trade #1157A. Check for the proper trade number written on the bulb and also be certain that you see three distinct conductors (one dead center) at the back of the bulb.
The turn/stop/park lights in the rear (the outboard ones) should have clear dual filament bulbs trade #1157
Great point. I bought new ones today and will remove, check ground and replace. I think I'm going to find a ground problem so i'm going to clean and check each bulb and ground before i get too far along Thanks for the input.!
You have all the symptoms of bad grounds at the sockets, either by corrosion or loss of connection. All the sockets have to be grounded for the lights to work correctly. Any ground you lose can cause current to pass through filaments where it shouldn't and not pass where it should. As said by others, your first two attacks should be correct bulbs, rotated correctly and making contact, and the bulb base must be grounded to the socket and the socket to a good ground. All the bulbs, any one can cause problems with others, they all use the same ground and 12v.
I once owned a 78 that had multiple light issues and the problem was inside the socket connector where the black wire plugs into it. I'll draw an arrow on the picture already provided above.
Thank you for the diagram, the odd thing is that the right rear break light (where I suspect at least part of issue might be originating), has a lot of "gunk" on the wires (more than the others) not sure what it is but if feels like old motor oil, grease or electrical tape residue.
I noticed this exact black wire (that you drew the arrow to in your pic) for that bulb socket felt like it might be loose or not as snug as the others. It was hard to tell because all of the gunk on it but I'm going to start right there. I will post an update after a little more work!
Good suggestion as lots of lighting quirkiness is due to a poor ground.
The location for that ground in on the frame rail on the drivers side about equidistant with the end of the muffler. There are two ground wires on it as mentioned above. Lay on your back and look up- you seriously cant miss it.
This ground wire causes a lot of problems as it is exposed to road and wet. It is just good PM to take it apart and get after it with a wire brush. I did mine two weeks ago-- 10 minutes tops and most of that time was spend looking for the correct size socket (10mm on an 82)
I found this last night. There was a breaded wire "hanging" from this ground bracket that was about 8" long. there were other wires still attached which i am going to clean up but... would you have any idea what that long thick ground wire is for? I was thinking the antenna motor as it was just long enough to reach that motor and the antenna is broken off so I would have no idea if the motor works or not. it was literally about 1/4 wide flat breaded wire that was just hanging from the grounding bar that was attached to the frame rail??
Good ahead and clean up and reconnect that long braided ground wire (strap). It may solve some of your problems. Though more likely ground related, It can also be a messed up switch onside the steering column. I would NOT dig into that until you have resolve all the ground issues. I am just stating that it is a possible problem area, not a likely one. Had similar problems on a Suburban, and it ended up being the column turn signal switch!
Last edited by Andy Tuttle; 08-04-2016 at 09:38 PM.
I am new to this form and just purchased a 1978 Corvette. I have a feeling I will be using this Form a lot. LOL The first issue is with the break lights and turn signals.
1> First issue...I have absolutely no turn signals at all. When I picked up the car 2 weeks ago the left signal worked fine but the right one just came on solid. Now nothing at all.
2> Secondly, when the running and headlights are on all front running lights, side markers, tail lights and headlights work just fine (except the driver front side marker which I just found had a burnt out bulb which I am replacing tomorrow) so all appears to be working fine.
3> The issues start when I depress the break;
1st lets look at what happens when the lights are OFF;
When I depress the break pedal several things happen 1> The inside dash turn signal indicators (both right and left) comes on solid. 2>The right rear BREAK LIGHT Does not light up but the left rear does. 3>The 2 front facing running lights light up (not any of the side markers).
2nd Lets look at what happens when the lights are ON: When I depress the break pedal 1> the, inside dash turn signal indicators (both right and left) comes on solid. 2>The right rear tail light goes out and the break light does NOT come on. 3>The left rear goes from tail light to break light just as it should 4>The front facing running lights light up BRIGHTER than they are as running lights.
I just replaced the two rear tail/break bulbs tonight. One was somewhat rusted but the inside of both sockets looked pretty good.
It feels like something in the right rear tail/break light is back feeding only the two front facing running lights as the front and rear SIDE markets do not light up when the headlights are off and I press the break. That said that doesn't support why i have no turn signals at all lights on or lights off.
Thanks for any help in where to start looking!!
Get hold of the 8 page wiring diagram for the '78..Check to verify that both the stop-running lite rear sockets are properly connected so the Same filament of the two in each lamp are getting power from the same source..There's 2 hots to each lamp holder..plus the ground IF the connection is switched. the brake lites won't work together..and you will have an odd array with lites on or off, turn signals etc..Jim
Last edited by jim in oregon; 08-05-2016 at 10:22 AM.
Get hold of the 8 page wiring diagram for the '78..Check to verify that both the stop-running lite rear sockets are properly connected so the Same filament of the two in each lamp are getting power from the same source..There's 2 hots to each lamp holder..plus the ground IF the connection is switched. the brake lites won't work together..and you will have an odd array with lites on or off, turn signals etc..Jim
There's an older thread where a SR forum member offers thecomplete accurate wiring diagrams specifically for your car for free..All you gotta do is send him a PM..They really help..Here's the link..
You can get complete light sockets w/pigtails from most GOOD auto supply houses..The original ground wire connection can be problematical on the originals..They are very inexpensive..VERY important that each stop brake lamp has the proper power wire connection to the same filament on EACH lamp..Take a look at your tailight connection wires that come out of the wiring harness in the rear..IF they have been cut-spliced in time past..quite probably they were not reconnected properly...here's the link to the wiring diagram fellow..Good luck..and keep us posted.jim
those are the right wiring diagrams..thanks for your assist to ED..!Jim
Interesting that the correct dual filament lambs go into the socket one way only..SO it's important that each stop lamp socket be wired-connected properly for brake lamps to light, flashers to operate, turn signals to function right..Aside from possible issues with ground wire poor connection in the socket, important that the TWO power leads to the sockets are not crosswired.THIS can happen if someone has cut and respliced the lamp socket(S) sometime in the past and not got the reconnection RIGHT.
08-03-2016, 10:56 PM
Help.. Tail lights are lighting the front parking lamps??
So today i bought a new signal flasher along with some new replacement bulbs and fuses. I think I'm going to start with cleaning and checking all grounds before i replace the Signal flasher but all items will be replaced. I will report back once i get the grounds cleaned and checked and all new bulbs and signal flasher installed!
Thanks for the input.!
