T/L CTSY fuse keeps blowing

[Cdog_96]

Hey everyone, working through issues on my 1987 Chevy v10 and my tl CTSY fuse keeps blowing when I turn my parking lights on. This is one click on the headlight switch, I have not gotten my instrument lights to turn on either and dimmer gives no response. The tail harness looks like it may have been hacked into but even then the splices look correct. It will blow a 30a fuse in a second, the green yellow and light green wires do get hot when I put a high amp fuse in there. It is hard to track the issue though with the fuse constantly blowing, could it be a bad ground in the back? The bulbs are good in the tail lights and parking lights, brake lights work fine. Any help or tips appreciated thank you !

 

[AuroraGirl]

Hey everyone, working through issues on my 1987 Chevy v10 and my tl CTSY fuse keeps blowing when I turn my parking lights on. This is one click on the headlight switch, I have not gotten my instrument lights to turn on either and dimmer gives no response. The tail harness looks like it may have been hacked into but even then the splices look correct. It will blow a 30a fuse in a second, the green yellow and light green wires do get hot when I put a high amp fuse in there. It is hard to track the issue though with the fuse constantly blowing, could it be a bad ground in the back? The bulbs are good in the tail lights and parking lights, brake lights work fine. Any help or tips appreciated thank you !

stop putting high amp fuses in! If you have a wire breakage or insufficiency you are probably going to create a flat out open circuit and maybe a fire.

SHOW Us what you see. you just described damage to wiring and didnt include a photo?

 

[RustyPile]

There are no written instructions for locating any specific fuse blowing short.. Shorts can occur on any wire anywhere in your vehicle.. The worse thing a person can do is install a heavier fuse. STOP doing that immediately. As Taylor said, doing so will eventually cause a fire. Fuses are designed to protect the wiring, not the device at the end of the wire.. Fuse rating is determined by the gauge of the wire it protects..


For years, I've been using the tool in the following link to aid me in locating a short. The tool isn't expensive nor difficult to use. Instructions for using it can be down loaded at the site.

Short Finder | Tool Aid

Use to locate shorts quickly and inexpensively in 12 volt automotive circuits.Eliminates need to remove upholstery and floor coverings.Operates through metal parts, panels, fiber and plastic materials.Connect leads to post of blown fuse then use induction type needle indicator to pinpoint...

www.toolaid.com

 

[RustyPile]

About the instrument lights not working... Those lights have a fuse all of their own, however, they get their power from the tail light circuit.. If the tail light fuse blows for any reason, the instrument lights also quit working even though their fuse is still intact.

 

[Cdog_96]

stop putting high amp fuses in! If you have a wire breakage or insufficiency you are probably going to create a flat out open circuit and maybe a fire.

SHOW Us what you see. you just described damage to wiring and didnt include a photo?

I can get a photo tomorrow, yes I understand that I shouldn't run larger fuses, i wasn't going to leave it in

 

[AuroraGirl]

I can get a photo tomorrow, yes I understand that I shouldn't run larger fuses, i wasn't going to leave it in

thats not the point, it only takes a moment for a fire to start. im glad it didnt but you may have made a resisted section of wire into ,effectively a dead short to the frame and another wire just hanging out doing nothing. not trying to be mean but you gotta slow er down lol.

You must be registered for see images attach

your bulb sockets wont look like this but you would be wise to show me both sides of the tail light harness like this, you need #8 screws for your tail lights if the fasteners fail.

 

[Ricko1966]

Use a light bulb instead of a fuse, a 194 bulb and socket works good. Now you won't have a dead short the bulb will be the load. Turn on your switch as before,now look at your 194 bulb,start wiggling harnesses watch your 194 bulb for changes in brightness blinking etc. Start disconnecting checking wires for bare spots,etc.

 

[Matt69olds]

Put a larger fuse than is specified, you will need some of this!!

Disconnect the battery, remove the bolt that holds the firewall electrical connector to the fuse box. There are 3 separate plugs, the smallest of the 3 is the taillight harness. Remove that plug from the bundle, plug in the other 2. Reconnect the battery, replace the fuse, pull the headlight switch. See if the fuse blows. If not, then the issue is in the taillight harness. If the truck has been wired for a trailer plug that’s the first place to look for problems.

Does the truck have a aftermarket radio? Factory Delco radios have a taillight feed in the harness to backlight the radio with the headlights on. Make sure that wire isn’t grounded somewhere.

Next, start chasing wires under the hood.

 

[AuroraGirl]

Put a larger fuse than is specified, you will need some of this!!

Disconnect the battery, remove the bolt that holds the firewall electrical connector to the fuse box. There are 3 separate plugs, the smallest of the 3 is the taillight harness. Remove that plug from the bundle, plug in the other 2. Reconnect the battery, replace the fuse, pull the headlight switch. See if the fuse blows. If not, then the issue is in the taillight harness. If the truck has been wired for a trailer plug that’s the first place to look for problems.

Does the truck have a aftermarket radio? Factory Delco radios have a taillight feed in the harness to backlight the radio with the headlights on. Make sure that wire isn’t grounded somewhere.

Next, start chasing wires under the hood.

doesnt the climate control bulb also do this? so be wise to check that for proper function I suppose?

 

[Ricko1966]

There are no written instructions for locating any specific fuse blowing short.. Shorts can occur on any wire anywhere in your vehicle.. The worse thing a person can do is install a heavier fuse. STOP doing that immediately. As Taylor said, doing so will eventually cause a fire. Fuses are designed to protect the wiring, not the device at the end of the wire.. Fuse rating is determined by the gauge of the wire it protects..


For years, I've been using the tool in the following link to aid me in locating a short. The tool isn't expensive nor difficult to use. Instructions for using it can be down loaded at the site.

Short Finder | Tool Aid

Use to locate shorts quickly and inexpensively in 12 volt automotive circuits.Eliminates need to remove upholstery and floor coverings.Operates through metal parts, panels, fiber and plastic materials.Connect leads to post of blown fuse then use induction type needle indicator to pinpoint...

www.toolaid.com

Funny thing is I have that tool,bought new,about 30 years ago,still,unused. I always can find the short before I need those. I wonder how much time I ve wasted finding shorts with a light and a multi meter over the span of 30 years!? A pic of my favorite tool for finding shorts. It's that same 194 bulb from a few posts back. And another one, of my favorite tool for holding wires while I solder, yep,that's 2 clips with a piece of solder between them.

 

[AuroraGirl]

Funny thing is I have that tool,bought new,about 30 years ago,still,unused. I always can find the short before I need those. I wonder how much time I ve wasted finding shorts with a light and a multi meter over the span of 30 years!? A pic of my favorite tool for finding shorts. It's that same 194 bulb from a few posts back. And another one, of my favorite tool for holding wires while I solder, yep,that's 2 clips with a piece of solder between them.

2 clips with solder between.. thats genius.

 

[RustyPile]

Funny thing is I have that tool,bought new,about 30 years ago,still,unused. I always can find the short before I need those. I wonder how much time I ve wasted finding shorts with a light and a multi meter over the span of 30 years!? A pic of my favorite tool for finding shorts. It's that same 194 bulb from a few posts back. And another one, of my favorite tool for holding wires while I solder, yep,that's 2 clips with a piece of solder between them.

I'm not sure just how you use that bulb, but I'm assuming you connect it across the terminals of the fuse that's blowing.. Of course, the light would come on and then go out when the short is found and "disconnected".. Rick, I would never be the person to criticize success. If the bulb load method works for you, by all means continue to depend on it..... If the bulb is in the fuse box and the person is flat of his back on a creeper under the vehicle or under the hood digging around looking for the short, how is the light bulb visible??

Referring to the short finder, that little "container" with the 2 leads, has a circuit breaker inside. The leads attach to those fuse terminals. The breaker makes and breaks enough that the wiring doesn't overheat.. The ammeter is an inductive pickup.. Starting at the fuse box wiring harness, the meter is moved along the harness. The meter senses the direction of the current flow. It "magically" points in the direction needed to move along the harness. When needle movement stops, the source/location of the short is found.. The tool will also work in the situation where a fusible link it consistently blowing.. Simply install the breaker in place of the fusible link and start at that point with the ammeter.

As I stated, I've had 100% success using the tool. I can usually locate the short WITHIN half an hour.. Most time, no disassembly is required in the locating process..

 

[Ricko1966]

I'm not sure just how you use that bulb, but I'm assuming you connect it across the terminals of the fuse that's blowing.. Of course, the light would come on and then go out when the short is found and "disconnected".. Rick, I would never be the person to criticize success. If the bulb load method works for you, by all means continue to depend on it..... If the bulb is in the fuse box and the person is flat of his back on a creeper under the vehicle or under the hood digging around looking for the short, how is the light bulb visible??

Referring to the short finder, that little "container" with the 2 leads, has a circuit breaker inside. The leads attach to those fuse terminals. The breaker makes and breaks enough that the wiring doesn't overheat.. The ammeter is an inductive pickup.. Starting at the fuse box wiring harness, the meter is moved along the harness. The meter senses the direction of the current flow. It "magically" points in the direction needed to move along the harness. When needle movement stops, the source/location of the short is found.. The tool will also work in the situation where a fusible link it consistently blowing.. Simply install the breaker in place of the fusible link and start at that point with the ammeter.

As I stated, I've had 100% success using the tool. I can usually locate the short WITHIN half an hour.. Most time, no disassembly is required in the locating process..

Oh I had no idea you had that tool yeah I bought one,still haven't used it. I'm going to go back through and read how you say it works,I always assumed it was a 2 prong flasher relay,and an inductive ammeter. I'm glad you've had luck with it. Real deal is old habits die hard,I started doing it the hard way years ago and just haven't given up yet.As for the light bulb you use it in place of the fuse and keep going back and looking at it or make one with longer leads. I have one with 6 foot leeds,it's cool because I can put it under a windshield washer blade and see it from the seat while I see if I'm getting power to say the starter solenoid,a washer, pump,injector,headlight,etc. The long one has tee pins instead of blade connectors,so I can backprobe a socket. I'll have to try my short finder out someday.Maybe. Damnit now you've got me excited to use it,I've never even tested it I'll I've ever done was bought it in looked at it,put in the tool box,and it just never comes to mind to use it.

 

[Ricko1966]

Okay,now I'm p!ssed and it's all @RustyPile s fault. Went to find this tool I never used and I could find the gauge,but not the sender,and in my search found my first MVI license its all curled up from just sitting in the tool box forever. Who'd a thunk? So anyway I always theorized the sender was a flasher relay,do you think it's a breaker or a relay. Second of all I want to straighten out my old license and frame it as an old treasure,ideas on how to flatten out curled stock paper?

 

[AuroraGirl]

Okay,now I'm p!ssed and it's all @RustyPile s fault. Went to find this tool I never used and I could find the gauge,but not the sender,and in my search found my first MVI license its all curled up from just sitting in the tool box forever. Who'd a thunk? So anyway I always theorized the sender was a flasher relay,do you think it's a breaker or a relay. Second of all I want to straighten out my old license and frame it as an old treasure,ideas on how to flatten out curled stock paper?

i would think a very flat surface plus a lot of weight laying very flat over it would be the best way.. but it is dirty, so be aware that it wont look that pretty.