C5 electrical problems
Thread Starter
Cruising
Joined: Jan 2023
Posts: 14
Likes: 0
C5 electrical problems
I posted about this a while ago but I still have no answer.
About a month ago I decided to install my halo taillights, they worked fine for about 2 days then I decided to install the hyper flash harness, after that my headlights wouldn't go up my running lights won't work,my gauge lights won't work, my hazards work sometimes and I have no brake lights. I emailed the company that I got the tail lights from and he said that I probably forgot to disconnect the battery and blew some fuses.I forgot to disconnect my battery but I checked all the possible fuses and non of them are bad. I am leaning towards that it could be the multifunction switch(the turn signal stalk switch) but I need more help before I buy that part because it is around $350. So if anyone has any clue what it could be or think that my guess of what's wrong is right then please let me know. Thank you
About a month ago I decided to install my halo taillights, they worked fine for about 2 days then I decided to install the hyper flash harness, after that my headlights wouldn't go up my running lights won't work,my gauge lights won't work, my hazards work sometimes and I have no brake lights. I emailed the company that I got the tail lights from and he said that I probably forgot to disconnect the battery and blew some fuses.I forgot to disconnect my battery but I checked all the possible fuses and non of them are bad. I am leaning towards that it could be the multifunction switch(the turn signal stalk switch) but I need more help before I buy that part because it is around $350. So if anyone has any clue what it could be or think that my guess of what's wrong is right then please let me know. Thank you
Instructor
Joined: Aug 2022
Posts: 243
Likes: 93
From: Ashburn, VA
With electrical and new parts, I always suggest reverse engineering the issue. Researching the hyper flash harness...it appears plug and play so...unplug it...return to factory configuration and bench test operation again. These cars have aging electronics and wiring so I'm always hesitant to mess with their electrics when they are working fine unless I'm re-wiring the entire car to upgrade. But for you to lose ALL of your light signals something greater then just a headlight and flasher harness install. it sounds like power to the light bus is gone (shorted feed wire? fusible link?)
My recommendation would be to do the above....test...if still nothing, get out your multimeter and see where you have power to and where you don't. If you have power nowhere...start looking at junctions and feeds for the lighting system.
Joe
My recommendation would be to do the above....test...if still nothing, get out your multimeter and see where you have power to and where you don't. If you have power nowhere...start looking at junctions and feeds for the lighting system.
Joe
Thread Starter
Cruising
Joined: Jan 2023
Posts: 14
Likes: 0
With electrical and new parts, I always suggest reverse engineering the issue. Researching the hyper flash harness...it appears plug and play so...unplug it...return to factory configuration and bench test operation again. These cars have aging electronics and wiring so I'm always hesitant to mess with their electrics when they are working fine unless I'm re-wiring the entire car to upgrade. But for you to lose ALL of your light signals something greater then just a headlight and flasher harness install. it sounds like power to the light bus is gone (shorted feed wire? fusible link?)
My recommendation would be to do the above....test...if still nothing, get out your multimeter and see where you have power to and where you don't. If you have power nowhere...start looking at junctions and feeds for the lighting system.
Joe
My recommendation would be to do the above....test...if still nothing, get out your multimeter and see where you have power to and where you don't. If you have power nowhere...start looking at junctions and feeds for the lighting system.
Joe
Instructor
Joined: Aug 2022
Posts: 243
Likes: 93
From: Ashburn, VA
Hey Joe,
Here is where I would start (some of these steps will require researching best way to access the ports in question):
Joe
Here is where I would start (some of these steps will require researching best way to access the ports in question):
- Pop the fuse panel and test EVERY fuse which has to do with the lights. Fuses to the naked eye can look good, but sometimes be bad. I don't think this is your issue but we are being scientific. Test all light fuses and rule those out early.
- Once those are verified...hit the light switch and turn it to marker lamps. At this point...if you can easily test the light switch (which is probably a pailn in the dick in a C5 lol) see if its getting power. A much easier test would be to pop one of the marker lights and test the pigtails with a multimeter. Lights are a simple + and - circut so that should be easy enough to sort out. Stick the probes in the appropriate slots and with the lights on you will either see 12.XX v or -12.XXv if you have probes backwards. The main point here is if you see 12V...you have power to the socket...which means the light switch is good and something else is afoul (i.e. a ground issue). If you see 0.00V with the light switch on, check another light (i.e headlights). if zero there as well...the light bus is dead (or not powered). You will have to back trace it.
- Get the C5 of your years electrical diagram and see what specifically feeds the light bus. Typically its feed via the main fuse bus, but its important to find EXACTLY what powers it. Once you do, use the multi meter to test that junction. It will most likely be 12+ constant all the time as it feeds the fuse box, but it could be ignition keyed on but that doubtful as light need to work with the ignition off as well.
Joe
Thread Starter
Cruising
Joined: Jan 2023
Posts: 14
Likes: 0
Hey Joe,
Here is where I would start (some of these steps will require researching best way to access the ports in question):
Joe
Here is where I would start (some of these steps will require researching best way to access the ports in question):
- Pop the fuse panel and test EVERY fuse which has to do with the lights. Fuses to the naked eye can look good, but sometimes be bad. I don't think this is your issue but we are being scientific. Test all light fuses and rule those out early.
- Once those are verified...hit the light switch and turn it to marker lamps. At this point...if you can easily test the light switch (which is probably a pailn in the dick in a C5 lol) see if its getting power. A much easier test would be to pop one of the marker lights and test the pigtails with a multimeter. Lights are a simple + and - circut so that should be easy enough to sort out. Stick the probes in the appropriate slots and with the lights on you will either see 12.XX v or -12.XXv if you have probes backwards. The main point here is if you see 12V...you have power to the socket...which means the light switch is good and something else is afoul (i.e. a ground issue). If you see 0.00V with the light switch on, check another light (i.e headlights). if zero there as well...the light bus is dead (or not powered). You will have to back trace it.
- Get the C5 of your years electrical diagram and see what specifically feeds the light bus. Typically its feed via the main fuse bus, but its important to find EXACTLY what powers it. Once you do, use the multi meter to test that junction. It will most likely be 12+ constant all the time as it feeds the fuse box, but it could be ignition keyed on but that doubtful as light need to work with the ignition off as well.
Joe
The lights work,high beams and low beams they just don’t pop up
