PIT5359D

Bulletin No.: PIT5359D
Published date: 12/4/2023
Preliminary Information
PIT5359D Radio Back Lighting Stays on After Key O / Dead
Battery / TCCM Repeat Failure
Models
Brand:
Model:
Model Years:
VIN:
from
to
Engine:
Transmissions:
Chevrolet
Silverado 1500
2014
All
All All
All
Chevrolet
Silverado
2015 - 2018
All
All All
All
Chevrolet
Silverado LD
2019
All
All All
All
Chevrolet
Silverado 2500/3500
2019
All
All All
All
Chevrolet
Silverado 4500 HD/5500 HD/6500 HD
2019 - 2023
All
All All
All
GMC
Sierra 1500
2014
All
All All
All
GMC
Sierra
2015 - 2018
All
All All
All
GMC
Sierra Limited
2019
All
All All
All
GMC
Sierra 2500/3500
2019
All
All All
All
Supersession Statement
This PI was superseded to update Models, Condition, and Recommendation sections. Please discard PIT5359C.
With Transfer Case (RPO NQF or NQH)
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition / Concern
Some owners may comment that their battery(ies) is going low or dead. Also, the radio
backlighting may stay on even after the ignition has been turned off, RAP cancelled, and the
key has been removed for several minutes. While diagnosing the concern,
stray/unwanted voltage may be present at the following fuses with the ignition key in the off
position: F23DL F22DL F30DL F31DL F32DL (look up your specific model's wiring diagram,
but examples are SI Doc ID 3819053 or 6119795). These fuses are all on the same Run/Crank
Ignition Buss Bar, located in the Left I/P Fuse Block, and should not have any voltage with
the ignition off. In some cases, there may only be 2 or 3 volts present, so a voltmeter must
be used when checking for voltage at these fuses.
The cause of this stray/unwanted voltage could be from the TCCM. The internal circuitry of
the TCCM may have been permanently damaged by a voltage spike, typically caused from an
aftermarket relay or solenoid. Once the TCCM is damaged, it can back feed voltage into the
fuse block onto fuses F23DL F22DL F30DL F31DL F32DL. This stray/unwanted voltage
will keep modules awake and the battery will go dead. If the TCCM is disconnected or fuse
F31DL is removed, the stray/unwanted voltage, at the fuses, will be gone.
Note: Because the IPC receive voltage from one of these fuses (F23DL), the IPC commonly is
misdiagnosed as the module causing the battery draw.
If the TCCM is replaced, the issue may only be corrected for a short time if the source of the
voltage spike is not found. In most cases, the voltage spike is caused by an aftermarket
accessory, which utilizes a solenoid or relay, that is wired onto the Run/Crank Ignition Buss
Bar. A couple common areas that these devices are connected to is the F30DL fuse or
directly hard wired to the X61A I/P Junction Block connector X7 terminal 11 or connector X5
terminal 35. If these solenoids or relays are not properly suppressed with a diode or
resistor, they will produce a voltage spike. The voltage spike can be transmitted back onto
the Run/Crank Ignition Buss Bar and permanently damage the TCCM.
Recommendations / Instructions
Important: DO NOT replace the TCCM until the root cause of the condition has been narrowed
to the solenoid/relay voltage spikes.
To prevent damage to any of the sensitive electronic components on the bussed circuit, the
solenoid/relay MUST have the control circuit suppressed with a diode. The diode will prevent
the voltage spikes from being transmitted onto the Run/Crank circuit.
Install a diode, P/N 12112422, across the coil of the solenoid. It is important that the striped
end of the diode be connected to the positive terminal of the coil and the other end of the
diode be connected to ground.
Important: Be sure to insulate the diode with heat shrink tubing before installing as shown in
the picture above.
Notice: Some solenoids/relays may only have a positive post and will get their ground
through their mounting bracket. In this case, the striped end of the diode is to be connected
to the positive terminal and other end should be connected to the ground of the
solenoid/relay.
Install a diode, P/N 12112422, across the coil of the relay. It is important that the striped end
of the diode be connected to the positive terminal of the coil and the other end of the diode
be connected to ground. Be sure to insulate the diode with heat shrink tubing before
installing.
Parts Information
Part Number
12112422
Description
Diode
Qty
1
Warranty Information
This repair will not be covered under warranty due to the failure being caused by an
aftermarket accessory.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is
resolved without completing every step, the remaining steps do not need to be performed.
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