Symptoms of a short?
07-18-2014, 07:26 PM
#1
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Symptoms of a short? Hello,
I have a 2004 silverado z71 crew cab and the gauge lights along with the climate control screen sometimes go out. When they do, I can tap on the dash above the gauge cluster and they will all come back on. I took the dash mostly apart and did not immediately see any shorts but I could not get a good look at most of the wiring as it went back down towards the firewall. Once or twice the truck would not crank so I held the key in the start position and tapped in the spot on the dash above the gauge cluster and it started right up.
My question is, if there is a short in the gauge cluster panel, could this cause the other symptoms downstream (climate control screen and buttons not to light up and ignition seemingly not receiving power)? I know there is an issue in the gauge cluster because the fuel gauge does not work properly ever, and the rest of the gauges have read incorrectly before.
Thanks for you help guys and girls,
Trey
I have a 2004 silverado z71 crew cab and the gauge lights along with the climate control screen sometimes go out. When they do, I can tap on the dash above the gauge cluster and they will all come back on. I took the dash mostly apart and did not immediately see any shorts but I could not get a good look at most of the wiring as it went back down towards the firewall. Once or twice the truck would not crank so I held the key in the start position and tapped in the spot on the dash above the gauge cluster and it started right up.
My question is, if there is a short in the gauge cluster panel, could this cause the other symptoms downstream (climate control screen and buttons not to light up and ignition seemingly not receiving power)? I know there is an issue in the gauge cluster because the fuel gauge does not work properly ever, and the rest of the gauges have read incorrectly before.
Thanks for you help guys and girls,
Trey
07-18-2014, 09:47 PM
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those clusters (at least the ones in the diesels anyway) have a known issue, I know on my dads old 03 (sold it a few weeks ago) he had to send the cluster off to have it rebuilt and I vaguely recall other signs of this cluster issue caused problems with the A/C and electronic 4x4 buttons.
here is something I just found with a quick google search of the phrase 04 silverado instrument cluster recall
http://www.gm-trucks.com/forums/topi...luster-recall/
I would say you should check in on the different truck forums and see what people say, also while your there look into the "4-high mod" all you have to do is a a diode (comes in like a pack of 3 or 4 from radio shack) that is used to "jump" one of the pins on the headlight relays that will keep your low beams on when you turn your high beams on, which gives you much improved lighting.
Basically this video minus the second one running to the DRL's:
here is something I just found with a quick google search of the phrase 04 silverado instrument cluster recall
http://www.gm-trucks.com/forums/topi...luster-recall/
I would say you should check in on the different truck forums and see what people say, also while your there look into the "4-high mod" all you have to do is a a diode (comes in like a pack of 3 or 4 from radio shack) that is used to "jump" one of the pins on the headlight relays that will keep your low beams on when you turn your high beams on, which gives you much improved lighting.
Basically this video minus the second one running to the DRL's:
07-18-2014, 09:55 PM
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those clusters (at least the ones in the diesels anyway) have a known issue, I know on my dads old 03 (sold it a few weeks ago) he had to send the cluster off to have it rebuilt and I vaguely recall other signs of this cluster issue caused problems with the A/C and electronic 4x4 buttons.
here is something I just found with a quick google search of the phrase 04 silverado instrument cluster recall
http://www.gm-trucks.com/forums/topi...luster-recall/
I would say you should check in on the different truck forums and see what people say, also while your there look into the "4-high mod" all you have to do is a a diode (comes in like a pack of 3 or 4 from radio shack) that is used to "jump" one of the pins on the headlight relays that will keep your low beams on when you turn your high beams on, which gives you much improved lighting.
Basically this video minus the second one running to the DRL's:
here is something I just found with a quick google search of the phrase 04 silverado instrument cluster recall
http://www.gm-trucks.com/forums/topi...luster-recall/
I would say you should check in on the different truck forums and see what people say, also while your there look into the "4-high mod" all you have to do is a a diode (comes in like a pack of 3 or 4 from radio shack) that is used to "jump" one of the pins on the headlight relays that will keep your low beams on when you turn your high beams on, which gives you much improved lighting.
Basically this video minus the second one running to the DRL's:
NEW DEVELOPMENT- the "reduced engine power" notification came on and wouldn't let me go faster than 25mph. I turned the truck off and on a few times and it went away but then came back after driving a little.
I have a thread going on performance trucks too. Both have given some good ideas so far. Keep them coming! I've gotta figure this out tomorrow.
Thanks
07-18-2014, 10:08 PM
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he never had anything like that, but he did have the ABS and BRAKE (the parking brake light on the dash) come on at the same time and the speedo start jumping 5-10 MPH variations and some other things and turned out to be his transfer case was shot.
what you describe is a "limp mode", try hooking it up to an OBD2 scanner and see what codes it's reporting, probably some sensor going out somewhere.
what you describe is a "limp mode", try hooking it up to an OBD2 scanner and see what codes it's reporting, probably some sensor going out somewhere.
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07-18-2014, 11:21 PM
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I saw on another forum where someone had similar issues, including the truck going into limp mode and a new / rebuilt cluster fixed it. Going to put one in tomorrow, assuming a local parts store in Amarillo has one in stock.
Keep the ideas coming. I'll update this post when I fix the issue.
Keep the ideas coming. I'll update this post when I fix the issue.
07-19-2014, 11:13 AM
#11
The term "short" is being used incorrectly a lot in this thread. So here is what a short is:
"Short" is a contraction of the phrase short circuit. A short circuit occurs when the wiring is damaged in a way that allows power to flow directly to ground bypassing the load (device) it was intended to power - the circuit is "shorter" because it doesn't flow through the load. With no load between the power source and ground, the current flow immediately rises to the maximum that the power source (battery or alternator) can produce which is way more than the wiring can handle. That's why we use fuses. The fuse is designed to blow and break the current flow before it can melt the wires and cause a fire. Fuses protect wiring not devices.
The most common cause of a short (other than dumbass wiring modifications) is having the insulation on a power wire break due to old age or from rubbing on some surface. The non-insulated portion then comes in contact with grounded metal (body, dash, fasteners, etc.) causing the current to short circuit and (hopefully) blow a fuse.
Shorts are not intermittent. If you can bang the dash and things work again then it's not a short - it's a loose connection somewhere or a defective device.
"Short" is a contraction of the phrase short circuit. A short circuit occurs when the wiring is damaged in a way that allows power to flow directly to ground bypassing the load (device) it was intended to power - the circuit is "shorter" because it doesn't flow through the load. With no load between the power source and ground, the current flow immediately rises to the maximum that the power source (battery or alternator) can produce which is way more than the wiring can handle. That's why we use fuses. The fuse is designed to blow and break the current flow before it can melt the wires and cause a fire. Fuses protect wiring not devices.
The most common cause of a short (other than dumbass wiring modifications) is having the insulation on a power wire break due to old age or from rubbing on some surface. The non-insulated portion then comes in contact with grounded metal (body, dash, fasteners, etc.) causing the current to short circuit and (hopefully) blow a fuse.
Shorts are not intermittent. If you can bang the dash and things work again then it's not a short - it's a loose connection somewhere or a defective device.
07-19-2014, 12:18 PM
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The term "short" is being used incorrectly a lot in this thread. So here is what a short is:
"Short" is a contraction of the phrase short circuit. A short circuit occurs when the wiring is damaged in a way that allows power to flow directly to ground bypassing the load (device) it was intended to power - the circuit is "shorter" because it doesn't flow through the load. With no load between the power source and ground, the current flow immediately rises to the maximum that the power source (battery or alternator) can produce which is way more than the wiring can handle. That's why we use fuses. The fuse is designed to blow and break the current flow before it can melt the wires and cause a fire. Fuses protect wiring not devices.
The most common cause of a short (other than dumbass wiring modifications) is having the insulation on a power wire break due to old age or from rubbing on some surface. The non-insulated portion then comes in contact with grounded metal (body, dash, fasteners, etc.) causing the current to short circuit and (hopefully) blow a fuse.
Shorts are not intermittent. If you can bang the dash and things work again then it's not a short - it's a loose connection somewhere or a defective device.
"Short" is a contraction of the phrase short circuit. A short circuit occurs when the wiring is damaged in a way that allows power to flow directly to ground bypassing the load (device) it was intended to power - the circuit is "shorter" because it doesn't flow through the load. With no load between the power source and ground, the current flow immediately rises to the maximum that the power source (battery or alternator) can produce which is way more than the wiring can handle. That's why we use fuses. The fuse is designed to blow and break the current flow before it can melt the wires and cause a fire. Fuses protect wiring not devices.
The most common cause of a short (other than dumbass wiring modifications) is having the insulation on a power wire break due to old age or from rubbing on some surface. The non-insulated portion then comes in contact with grounded metal (body, dash, fasteners, etc.) causing the current to short circuit and (hopefully) blow a fuse.
Shorts are not intermittent. If you can bang the dash and things work again then it's not a short - it's a loose connection somewhere or a defective device.
So let's rephrase the question - could a lose connection or short in the cluster itself cause the other issues? Intermittent loss of power to ignition, the diagnostic port, blown cig lighter fuse?
Thanks
07-19-2014, 02:16 PM
#13
Short answer... No. (pun intended) 
No, if you bang on the dash and it caused a short, it would only happen once because the short would cause a fuse to blow and there would be no power for it to happen again.
No, a loose connection in the instrument cluster could cause loss of ignition but not the ODB II port or cigarette lighter because those circuits don't share power with the cluster. Both the OBD II port and the lighter run off the same CIG/ACCY fuse so the blown fuse would account for the diagnostics port problem. It is possible there is a short in that circuit or the fuse could have blown because of something getting into the lighter socket itself, shorting the contacts.
No, if you bang on the dash and it caused a short, it would only happen once because the short would cause a fuse to blow and there would be no power for it to happen again.
No, a loose connection in the instrument cluster could cause loss of ignition but not the ODB II port or cigarette lighter because those circuits don't share power with the cluster. Both the OBD II port and the lighter run off the same CIG/ACCY fuse so the blown fuse would account for the diagnostics port problem. It is possible there is a short in that circuit or the fuse could have blown because of something getting into the lighter socket itself, shorting the contacts.