I keep blowing the 5A INST fuse
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Supreme Member
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Joined: May 2002
Posts: 4,449
Likes: 8
From: Everett, WA
Car: 87' IROC
Engine: L98
Transmission: T56
I keep blowing the 5A INST fuse
Heres the deal.
1987 Camaro IROC-Z 350TPI
One night I was driving around a corner and suddenly my instrument panel lights went out. I found the 5A INST fuse was blown. I replaced it, and it immediatly blew again. I replaced the headlight/dimmer switch. This did not help. Also, when I pulled the driver side foot cover, a red wire droped down. It has a loop at the end like a ground wire, but it is red. Does anyone know where this goes? It also has a 0.5A fuse on the wire. The fuse is in a white plastic case. I have attached pics below.
Anyone have any idea what is going on here?
Where does that red wire go?
For reference:
headlights work
tail lights work
instrument panel lights do not work
dome light works
curtousey lights work
fog lights work
thanks
John
1987 Camaro IROC-Z 350TPI
One night I was driving around a corner and suddenly my instrument panel lights went out. I found the 5A INST fuse was blown. I replaced it, and it immediatly blew again. I replaced the headlight/dimmer switch. This did not help. Also, when I pulled the driver side foot cover, a red wire droped down. It has a loop at the end like a ground wire, but it is red. Does anyone know where this goes? It also has a 0.5A fuse on the wire. The fuse is in a white plastic case. I have attached pics below.
Anyone have any idea what is going on here?
Where does that red wire go?
For reference:
headlights work
tail lights work
instrument panel lights do not work
dome light works
curtousey lights work
fog lights work
thanks
John
Thread Starter
Supreme Member
iTrader: (2)
Joined: May 2002
Posts: 4,449
Likes: 8
From: Everett, WA
Car: 87' IROC
Engine: L98
Transmission: T56
Thread Starter
Supreme Member
iTrader: (2)
Joined: May 2002
Posts: 4,449
Likes: 8
From: Everett, WA
Car: 87' IROC
Engine: L98
Transmission: T56
Re: I keep blowing the 5A INST fuse
Yes, one of my gauge cluster lights was burnt out in such a way that the circuit shorted causing the fuse to blow. How dumb, but something to check out. Replaced the light, now everything worked.
Re: I keep blowing the 5A INST fuse
Thanks. It doesn't look as if one my lights are out, but I'll check. This just started out of the blue, so it might be a blown light that's causing the problem. I'll let you know if it works or not...
Junior Member
Joined: Jul 2009
Posts: 68
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From: Oregon
Car: 92 GMC Sierra 2500
Engine: 5.7l
Transmission: 4L70
Axle/Gears: GT4 3.73
Re: I keep blowing the 5A INST fuse
The first thing I check for, with fuse blowing problems, is do-it-yourself add-on wiring connected into the circuit.
Generally the circuits, wiring, and fuses are designed for the factory devices attached and not for add-on things. People add things on to these circuits, then fuses start blowing.
Also add-on wiring is loose and not protected like factory wiring. Factory wiring has tape around the wires and that black plastic tubing. This protects the wires from rubbing up against sharp metal objects and shorting to ground.
So if you can, follow the wire from that circuit and see if something is connected on to that circuit somewhere. Then remove it. Then return the wires to the "factory look" - wrapped with tape and black tubing over that.
Then for properly adding on something electrical and not having fuse blowing problems, wire directly to the main electrical distribution lugs and install your own in-line fuse. Use the correct wire size and fuse for the amperage the device is rated for. Here is a table for that...
Wire gauge sizes for 12V wiring
22 - 5Amps
20 - 8Amps
18 - 10Amps
16 - 20Amps
14 - 40Amps
12 - 60Amps
10 - 100Amps
8 - 150Amps
The fuse is to protect the specific wire size. Using a larger fuse will not protect the wiring any more and you risk a fire or melted wires.
You can also test the amperage being used in circuits with an amp meter (ammeter). Get one which is rated for 100 amps DC or higher. (Must say 100 amps DC, not AC!) The multimeters sold in auto parts stores which are rated at 10 amps DC are worthless for todays vehicles which can have 100 amp alternators. If you test a circuit beyond 10 amps with these meters, it will wreck them!
Generally the circuits, wiring, and fuses are designed for the factory devices attached and not for add-on things. People add things on to these circuits, then fuses start blowing.
Also add-on wiring is loose and not protected like factory wiring. Factory wiring has tape around the wires and that black plastic tubing. This protects the wires from rubbing up against sharp metal objects and shorting to ground.
So if you can, follow the wire from that circuit and see if something is connected on to that circuit somewhere. Then remove it. Then return the wires to the "factory look" - wrapped with tape and black tubing over that.
Then for properly adding on something electrical and not having fuse blowing problems, wire directly to the main electrical distribution lugs and install your own in-line fuse. Use the correct wire size and fuse for the amperage the device is rated for. Here is a table for that...
Wire gauge sizes for 12V wiring
22 - 5Amps
20 - 8Amps
18 - 10Amps
16 - 20Amps
14 - 40Amps
12 - 60Amps
10 - 100Amps
8 - 150Amps
The fuse is to protect the specific wire size. Using a larger fuse will not protect the wiring any more and you risk a fire or melted wires.
You can also test the amperage being used in circuits with an amp meter (ammeter). Get one which is rated for 100 amps DC or higher. (Must say 100 amps DC, not AC!) The multimeters sold in auto parts stores which are rated at 10 amps DC are worthless for todays vehicles which can have 100 amp alternators. If you test a circuit beyond 10 amps with these meters, it will wreck them!
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Re: I keep blowing the 5A INST fuse
Billy Bob;
I purchased this car brand new in 1988, and have never altered it. Everything is as it was from the factory with no add ons. However, I plan to give it a thorough look-see this weekend. Thanks for your input
I purchased this car brand new in 1988, and have never altered it. Everything is as it was from the factory with no add ons. However, I plan to give it a thorough look-see this weekend. Thanks for your input
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