Turn Signal Short is driving my crazy
10-14-2021, 05:01 PM
#1
TECH Apprentice
Thread Starter
Turn Signal Short is driving my crazy The car is a 4th Gen F-body (2001 Trans Am if that matters)
Today my turn signals stopped working. I saw that I blew a fuse so I replaced it. It blew AS SOON AS I TURNED THE KEY TO THE ON POSITION. Second fuse same thing. I left the key in the on position and inserted a third fuse. It burned INSTANTANEOUSLY. Obviously I have a short of some kind. Hazard signals work fine and it looks like there's no bulb that's out. I'm guessing if there was a wiring going to the turn signal bulbs it would effect the hazard fuse as well? Is my thinking correct?
Note: I also tried inserting a fuse with the flasher removed. It burned out. I'm a complete dunce when it comes to electronics, but I'm guessing it means the short is between the fuse box and the relay? My mechanic is booked solid for weeks and I'd honestly rather trouble shoot as much as I can myself to save a few bucks and not wait for weeks. Plus I don't want to find another mechanic.
Today my turn signals stopped working. I saw that I blew a fuse so I replaced it. It blew AS SOON AS I TURNED THE KEY TO THE ON POSITION. Second fuse same thing. I left the key in the on position and inserted a third fuse. It burned INSTANTANEOUSLY. Obviously I have a short of some kind. Hazard signals work fine and it looks like there's no bulb that's out. I'm guessing if there was a wiring going to the turn signal bulbs it would effect the hazard fuse as well? Is my thinking correct?
Note: I also tried inserting a fuse with the flasher removed. It burned out. I'm a complete dunce when it comes to electronics, but I'm guessing it means the short is between the fuse box and the relay? My mechanic is booked solid for weeks and I'd honestly rather trouble shoot as much as I can myself to save a few bucks and not wait for weeks. Plus I don't want to find another mechanic.
Last edited by 2001ws6ft; 10-14-2021 at 05:59 PM.
10-14-2021, 08:08 PM
#2
You are doing a great job! Are you sure that you removed the correct flasher? The turn signal flasher is on the right side of the dash/steering wheel and the hazard flasher (separate one) is on the left side of the dash/steering wheel.
If so, you are close to the short. There should just be one wire straight from the fuse to the flasher at the start of the circuit:
^ If you get an account at AutoZone.com, you can access all of the car's schematics. This circuit is one of the more complicated ones and you need to trace it over several pages for the turn signals, DRLs, parking lamps, etc. but the picture above is the start of where you are looking for this.
If so, you are close to the short. There should just be one wire straight from the fuse to the flasher at the start of the circuit:
^ If you get an account at AutoZone.com, you can access all of the car's schematics. This circuit is one of the more complicated ones and you need to trace it over several pages for the turn signals, DRLs, parking lamps, etc. but the picture above is the start of where you are looking for this.
The following 2 users liked this post by wssix99:
2001ws6ft (10-14-2021), WhiteBird00 (10-20-2021)
10-14-2021, 08:31 PM
#3
TECH Apprentice
Thread Starter
You are doing a great job! Are you sure that you removed the correct flasher? The turn signal flasher is on the right side of the dash/steering wheel and the hazard flasher (separate one) is on the left side of the dash/steering wheel.
If so, you are close to the short. There should just be one wire straight from the fuse to the flasher at the start of the circuit:
^ If you get an account at AutoZone.com, you can access all of the car's schematics. This circuit is one of the more complicated ones and you need to trace it over several pages for the turn signals, DRLs, parking lamps, etc. but the picture above is the start of where you are looking for this.
If so, you are close to the short. There should just be one wire straight from the fuse to the flasher at the start of the circuit:
^ If you get an account at AutoZone.com, you can access all of the car's schematics. This circuit is one of the more complicated ones and you need to trace it over several pages for the turn signals, DRLs, parking lamps, etc. but the picture above is the start of where you are looking for this.
Ok. Yes, I removed the correct flasher, I even double checked to see the hazards were working with it removed and they were. So I'm on the right track? I don't have to track any shorts past the flasher? It's all under there? All I have to do is figure out that mess under there and see where the wire from the fuse box to the flasher is......It's a mess under there. I only glanced at it for a few minutes, but it's going to take me a bit to figure it out.
Worst case scenario, I can't find where that wire goes........Would it be half as$ed if I remove that wire from the fuse box and create a new one going from the fuse to the flasher?
Last edited by 2001ws6ft; 10-14-2021 at 08:36 PM.
10-14-2021, 10:49 PM
#4
I think you can find this easy. You are doing a great job and you have proved yourself wrong in the "moron department" as you've 95% solved the problem.
The next thing to do is a continuity check between the fuse panel and the flasher socket. You can do that a number of ways - check for videos on YouTube. You want to do that continuity check on the brown wire. Then do a continuity check between the brown wire connections at the fuse box and at the flasher socket compared to ground. (One wire at each of those places and then the other wire on a metal part of the body.) That should confirm what is up before you go diggig into wire looms.
The next thing to do is a continuity check between the fuse panel and the flasher socket. You can do that a number of ways - check for videos on YouTube. You want to do that continuity check on the brown wire. Then do a continuity check between the brown wire connections at the fuse box and at the flasher socket compared to ground. (One wire at each of those places and then the other wire on a metal part of the body.) That should confirm what is up before you go diggig into wire looms.
10-15-2021, 02:30 PM
#5
TECH Apprentice
Thread Starter
I think you can find this easy. You are doing a great job and you have proved yourself wrong in the "moron department" as you've 95% solved the problem.
The next thing to do is a continuity check between the fuse panel and the flasher socket. You can do that a number of ways - check for videos on YouTube. You want to do that continuity check on the brown wire. Then do a continuity check between the brown wire connections at the fuse box and at the flasher socket compared to ground. (One wire at each of those places and then the other wire on a metal part of the body.) That should confirm what is up before you go diggig into wire looms.
The next thing to do is a continuity check between the fuse panel and the flasher socket. You can do that a number of ways - check for videos on YouTube. You want to do that continuity check on the brown wire. Then do a continuity check between the brown wire connections at the fuse box and at the flasher socket compared to ground. (One wire at each of those places and then the other wire on a metal part of the body.) That should confirm what is up before you go diggig into wire looms.
10-15-2021, 04:25 PM
#6
TECH Apprentice
Thread Starter
I think you can find this easy. You are doing a great job and you have proved yourself wrong in the "moron department" as you've 95% solved the problem.
The next thing to do is a continuity check between the fuse panel and the flasher socket. You can do that a number of ways - check for videos on YouTube. You want to do that continuity check on the brown wire. Then do a continuity check between the brown wire connections at the fuse box and at the flasher socket compared to ground. (One wire at each of those places and then the other wire on a metal part of the body.) That should confirm what is up before you go diggig into wire looms.
The next thing to do is a continuity check between the fuse panel and the flasher socket. You can do that a number of ways - check for videos on YouTube. You want to do that continuity check on the brown wire. Then do a continuity check between the brown wire connections at the fuse box and at the flasher socket compared to ground. (One wire at each of those places and then the other wire on a metal part of the body.) That should confirm what is up before you go diggig into wire looms.
10-16-2021, 09:12 AM
#7
I missed the detail that this happens the minute you turn the key to the on position. (I read it and processed it in my brain that you hit the turn signal.)
So... If you removed the flasher then I would think it highly unlikely that the turn signals are your issue. I'd next unplug your TCS switch (if you have one), your park/neutral switches (as appropriate for your transmission), and then your DRL module. Then plug them back in one by one until you win Bingo. That should help you narrow it down to the problem circuit.
... If I had to direct suspision to any of these mugs, it would be the DRL circuit because it's the most complex.
The following 2 users liked this post by wssix99:
2001ws6ft (10-16-2021), WhiteBird00 (10-20-2021)
Trending Topics
10-16-2021, 10:10 AM
#8
TECH Apprentice
Thread Starter
Yes, there are other circuits on that fuse, which you can see under the "Fuse Block Details Schematics"
I missed the detail that this happens the minute you turn the key to the on position. (I read it and processed it in my brain that you hit the turn signal.)
So... If you removed the flasher then I would think it highly unlikely that the turn signals are your issue. I'd next unplug your TCS switch (if you have one), your park/neutral switches (as appropriate for your transmission), and then your DRL module. Then plug them back in one by one until you win Bingo. That should help you narrow it down to the problem circuit.
... If I had to direct suspision to any of these mugs, it would be the DRL circuit because it's the most complex.
I missed the detail that this happens the minute you turn the key to the on position. (I read it and processed it in my brain that you hit the turn signal.)
So... If you removed the flasher then I would think it highly unlikely that the turn signals are your issue. I'd next unplug your TCS switch (if you have one), your park/neutral switches (as appropriate for your transmission), and then your DRL module. Then plug them back in one by one until you win Bingo. That should help you narrow it down to the problem circuit.
... If I had to direct suspision to any of these mugs, it would be the DRL circuit because it's the most complex.
Last edited by 2001ws6ft; 10-16-2021 at 10:19 AM.
10-16-2021, 01:12 PM
#9
Yes, there are other circuits on that fuse, which you can see under the "Fuse Block Details Schematics"
I missed the detail that this happens the minute you turn the key to the on position. (I read it and processed it in my brain that you hit the turn signal.)
So... If you removed the flasher then I would think it highly unlikely that the turn signals are your issue. I'd next unplug your TCS switch (if you have one), your park/neutral switches (as appropriate for your transmission), and then your DRL module. Then plug them back in one by one until you win Bingo. That should help you narrow it down to the problem circuit.
... If I had to direct suspision to any of these mugs, it would be the DRL circuit because it's the most complex.
I missed the detail that this happens the minute you turn the key to the on position. (I read it and processed it in my brain that you hit the turn signal.)
So... If you removed the flasher then I would think it highly unlikely that the turn signals are your issue. I'd next unplug your TCS switch (if you have one), your park/neutral switches (as appropriate for your transmission), and then your DRL module. Then plug them back in one by one until you win Bingo. That should help you narrow it down to the problem circuit.
... If I had to direct suspision to any of these mugs, it would be the DRL circuit because it's the most complex.
10-17-2021, 01:24 PM
#10
TECH Apprentice
Thread Starter
Yes, there are other circuits on that fuse, which you can see under the "Fuse Block Details Schematics"
I missed the detail that this happens the minute you turn the key to the on position. (I read it and processed it in my brain that you hit the turn signal.)
So... If you removed the flasher then I would think it highly unlikely that the turn signals are your issue. I'd next unplug your TCS switch (if you have one), your park/neutral switches (as appropriate for your transmission), and then your DRL module. Then plug them back in one by one until you win Bingo. That should help you narrow it down to the problem circuit.
... If I had to direct suspision to any of these mugs, it would be the DRL circuit because it's the most complex.
I missed the detail that this happens the minute you turn the key to the on position. (I read it and processed it in my brain that you hit the turn signal.)
So... If you removed the flasher then I would think it highly unlikely that the turn signals are your issue. I'd next unplug your TCS switch (if you have one), your park/neutral switches (as appropriate for your transmission), and then your DRL module. Then plug them back in one by one until you win Bingo. That should help you narrow it down to the problem circuit.
... If I had to direct suspision to any of these mugs, it would be the DRL circuit because it's the most complex.
A million thanks!
The following users liked this post:
WhiteBird00 (10-20-2021)
10-17-2021, 10:48 PM
#11
These electronic schematics come from Autozone.com. If you sign up for an account there, you can access them under the Repair section. (These are the same schematics published in the GM Factory Service Manuals.) The big additional advangate of the FMS's is that they have extensive trouble shooting guides and proceedures.
thank you so much for your help. It's so much easier with someone giving you hints and walking you through diagnosing.. so i unplugged the backup switch and retried. I put in a 10 amp fuse (instead of the 20 it calls for) and it didn't blow. I tested out the turn signals....they work. If I were to guess, the switch has gone bad. Or there may be a short upstream of the switch. I ordered a new one and I'm going to see what happens. I think that's the next logical step.
Last edited by wssix99; 10-18-2021 at 07:44 AM.
The following users liked this post:
2001ws6ft (10-29-2021)
10-20-2021, 08:59 AM
#12
Wow, I go on vacation for a week and I'm not even missed. 
wssix99 has given you great advice and, contrary to your own modesty, you have done a really good job of diagnosing and tracing your problem. It's good to see someone going at it logically and not just throwing parts at a problem as so often happens these days.
wssix99 has given you great advice and, contrary to your own modesty, you have done a really good job of diagnosing and tracing your problem. It's good to see someone going at it logically and not just throwing parts at a problem as so often happens these days.
The following users liked this post:
2001ws6ft (10-29-2021)
The following users liked this post:
2001ws6ft (10-29-2021)
The following users liked this post:
2001ws6ft (10-29-2021)
10-29-2021, 08:45 PM
#15
TECH Apprentice
Thread Starter
Thank you so much for your help. Diagnosing electrical issues is so much better with guidance. It turns out that it was just a stupid back up switch sensor for the rear lights. Well, at least that's what I'm guessing. It hasn't blown a fuse since I replaced it and I put in a 10 amp fuse instead of a 20 amp fuse that it's rated for. Before, it would blow INSTANTANEOUSLY with a 20 amp fuse. I'm going to assume victory. 
The following users liked this post:
wssix99 (10-30-2021)