Thinkenn
Member
Hey everybody.
Okay so tonight I had a repeat of a problem that occurred 6 months ago and I looked around the forum and no one had yet mentioned anything related to it, so I thought I would share the details.
Have you ever had your gauges kinda go half dead? As in, you loose your tach, speedo, engine temp, and trans temp, along with your PRND123 / odometer lcd..it just goes dark whilst amazingly your oil pressure / volt's gauges stay? Then almost a second later a MIL pops up and you are left kind of scratching your head wondering the bloody hell just happened?
You press your trip/clear and suddenly it all comes back, but the abs light is on along with the park brake.. the message center is red about the battery and the seat belt light is lit..(your wearing it)....things settle.. (hmm you think, reminds me of turning the key from off to run) but as soon as you let the trip button go it goes right back to the way it was before with the MIL lit? It never killed the truck.. still driving.. so you get it home, and plug your scanner into it. The MIL comes back that there exists a shift solenoid problem with the transmission , 2-3 not working, etc.. PCM.. low voltage.. yeah.. "Yea.. okay", you say, "But why are my gauges dead?"
Well. BEFORE you do anything. DO this first.
Open your hood. Check on the back of the engine, the passenger and driver side where it sits closest to the fire-wall. Put your feelers back there and grope deep for a grounding strap/single wire. It might be a 12-14ga insulated wire, or a metal braided shoelace.. Be gentle. You should find something. If you find one.. check/inspect/clean the connections where it connects to the engine and where it connects to the fire-wall. If you are like me, and you wash the engine now and then at the car wash, or you own a 16 year old truck.. the un-protected ends do corrode over time. If for any case you are un-fortunate like ME 6 months ago and DON'T find one..at all.. Do your trucks electrical system a colossal favor and install one. Because if you DON'T, the instrument clusters gonna get it.. its gonna crater. The ground strap (if your making one) just has to go from anything metal on the engine block to any metal ON the firewall. Make sure you make it long enough to permit flex, but as short as possible for low resistance.
Let me tell you why.
It has to do with the voltage spike that's generated thru induction when an electro-magnets created magnetic field collapses.
The shift solenoids in the auto trans have voltage spikes, every time the solenoids loose power there's a very brief high voltage spike. As the battery's negative terminal is grounded up front, and not to the engine itself, ensuring there exists a strap from the engine to the body of the vehicle is pretty important as it maintains a unified ground path between the transmission and the negative battery post. Allowing the safe disbursement (draining) of any harmful voltage irregularities away from sensitive electronics and directly to the negative battery terminal.
I dug thru and found a GM white-paper on some models missing the ground strap. It was also a problem that existed on some trucks that had a dealer installed fresh engine, and the tech having not re-installed the strap.. etc... But the white paper did not explain WHY the problem occurred, just what to do and how to fix. A boo boo.
Whats going on here, well.. Resistance. The instrument clusters connections are not near heavy enough to handle the kind of repeated electron loading when the transmission's solenoids dis-engage. When any solenoids energize, the coil creates a magnetic field around the slider, when it reaches its peak, the slider moves by (EMF) the pushing (or pulling) force generated when magnetic field lines interact with the flux lines inherent in the slider. When the power is cut from the solenoid, the coils magnetic field collapses, resulting in an induced voltage spike within the coil, and also the wires attached to the coil. Because the wires do not have diodes on them, the current flows backwards up the wires, and energizes a circuit in reverse. Electron backwash. IF the rare occurrence happens where the transmission solenoids do not have a dedicated route to unified ground, the voltage spike induced on the circuit will instead ground THRU the next available shortest route which is (you guessed it) right thru the bloody gauge cluster.. over time the spike(ing) will cause damage. Because a solenoid draws the most amps during the building of the magnetic field, if for whatever reason the building and collapsing of the field happen very close in time to one another, the resulting electron shock-wave can rip thru the un-protected circuitry and do damage. Stepper motors crap out, LCD failure, blown fuses, one side of the power circuit will fail. Its just busts sh*t aweful..
I reached behind the engine, and on the passenger side where the wire on mine is installed, and discovered it was loose. My heart like sank. The engine rocking side to side in the engine bay over time slowly worked at the ring terminal bolt. When.. I have no idea.. The cluster failing was the 1st and only indication something was wrong.
I tightened up the ground strap and cleared the MIL. I took the truck out for a 10KM run.. and no MIL, shifts from 2nd to 3rd just fine. Just no gauges.
So, I'll see what I can do about that in the daylight. Hopefully its just solder.. but I dunno.. And I might re-think that ground strap.. maybe install a backup.. two straps.. one on each side..
My cluster has the trans temp guage in it, I have the old one..but its problem is in the circuits.. and I am dreading that this one has been Gaboroned the same.
Has anyone else had this happen to them?
Okay so tonight I had a repeat of a problem that occurred 6 months ago and I looked around the forum and no one had yet mentioned anything related to it, so I thought I would share the details.
Have you ever had your gauges kinda go half dead? As in, you loose your tach, speedo, engine temp, and trans temp, along with your PRND123 / odometer lcd..it just goes dark whilst amazingly your oil pressure / volt's gauges stay? Then almost a second later a MIL pops up and you are left kind of scratching your head wondering the bloody hell just happened?
You press your trip/clear and suddenly it all comes back, but the abs light is on along with the park brake.. the message center is red about the battery and the seat belt light is lit..(your wearing it)....things settle.. (hmm you think, reminds me of turning the key from off to run) but as soon as you let the trip button go it goes right back to the way it was before with the MIL lit? It never killed the truck.. still driving.. so you get it home, and plug your scanner into it. The MIL comes back that there exists a shift solenoid problem with the transmission , 2-3 not working, etc.. PCM.. low voltage.. yeah.. "Yea.. okay", you say, "But why are my gauges dead?"
Well. BEFORE you do anything. DO this first.
Open your hood. Check on the back of the engine, the passenger and driver side where it sits closest to the fire-wall. Put your feelers back there and grope deep for a grounding strap/single wire. It might be a 12-14ga insulated wire, or a metal braided shoelace.. Be gentle. You should find something. If you find one.. check/inspect/clean the connections where it connects to the engine and where it connects to the fire-wall. If you are like me, and you wash the engine now and then at the car wash, or you own a 16 year old truck.. the un-protected ends do corrode over time. If for any case you are un-fortunate like ME 6 months ago and DON'T find one..at all.. Do your trucks electrical system a colossal favor and install one. Because if you DON'T, the instrument clusters gonna get it.. its gonna crater. The ground strap (if your making one) just has to go from anything metal on the engine block to any metal ON the firewall. Make sure you make it long enough to permit flex, but as short as possible for low resistance.
Let me tell you why.
It has to do with the voltage spike that's generated thru induction when an electro-magnets created magnetic field collapses.
The shift solenoids in the auto trans have voltage spikes, every time the solenoids loose power there's a very brief high voltage spike. As the battery's negative terminal is grounded up front, and not to the engine itself, ensuring there exists a strap from the engine to the body of the vehicle is pretty important as it maintains a unified ground path between the transmission and the negative battery post. Allowing the safe disbursement (draining) of any harmful voltage irregularities away from sensitive electronics and directly to the negative battery terminal.
I dug thru and found a GM white-paper on some models missing the ground strap. It was also a problem that existed on some trucks that had a dealer installed fresh engine, and the tech having not re-installed the strap.. etc... But the white paper did not explain WHY the problem occurred, just what to do and how to fix. A boo boo.
Whats going on here, well.. Resistance. The instrument clusters connections are not near heavy enough to handle the kind of repeated electron loading when the transmission's solenoids dis-engage. When any solenoids energize, the coil creates a magnetic field around the slider, when it reaches its peak, the slider moves by (EMF) the pushing (or pulling) force generated when magnetic field lines interact with the flux lines inherent in the slider. When the power is cut from the solenoid, the coils magnetic field collapses, resulting in an induced voltage spike within the coil, and also the wires attached to the coil. Because the wires do not have diodes on them, the current flows backwards up the wires, and energizes a circuit in reverse. Electron backwash. IF the rare occurrence happens where the transmission solenoids do not have a dedicated route to unified ground, the voltage spike induced on the circuit will instead ground THRU the next available shortest route which is (you guessed it) right thru the bloody gauge cluster.. over time the spike(ing) will cause damage. Because a solenoid draws the most amps during the building of the magnetic field, if for whatever reason the building and collapsing of the field happen very close in time to one another, the resulting electron shock-wave can rip thru the un-protected circuitry and do damage. Stepper motors crap out, LCD failure, blown fuses, one side of the power circuit will fail. Its just busts sh*t aweful..
I reached behind the engine, and on the passenger side where the wire on mine is installed, and discovered it was loose. My heart like sank. The engine rocking side to side in the engine bay over time slowly worked at the ring terminal bolt. When.. I have no idea.. The cluster failing was the 1st and only indication something was wrong.
I tightened up the ground strap and cleared the MIL. I took the truck out for a 10KM run.. and no MIL, shifts from 2nd to 3rd just fine. Just no gauges.
So, I'll see what I can do about that in the daylight. Hopefully its just solder.. but I dunno.. And I might re-think that ground strap.. maybe install a backup.. two straps.. one on each side..
My cluster has the trans temp guage in it, I have the old one..but its problem is in the circuits.. and I am dreading that this one has been Gaboroned the same.
Has anyone else had this happen to them?
