Why Your 2020 Silverado Won't Start (And How to Fix It)

How to Fix Battery Issue

A dead battery or electrical gremlin can turn your 2020 Chevrolet Silverado from a reliable workhorse into a frustrating headache. Owners report a range of symptoms from complete no-start conditions to phantom power drains and accessory issues. The root cause often points back to the vehicle's complex electrical and fuel systems, where a single faulty component or damaged wire can leave you stranded. As one owner shared about their troubleshooting journey: "Found some chaffed wires going to the fuel pump control module got those fixed then the truck wouldn’t do anything again no crank no start." This guide will walk you through the diagnosis and repair process based on real owner experiences.

Symptoms

The most common and alarming symptom reported by owners is a no-crank, no-start condition. The truck has dash power, lights, and accessories, but when you turn the key or push the start button, absolutely nothing happens from the starter. One owner detailed this exact scenario: "I was driving and my truck randomly lost engine power... it has dash power, lights come on just won’t turn over, you can apply power to the starter and it’ll spin over." This indicates the battery has power, but the command signal from the truck's computer isn't reaching the starter.

Another frequent symptom is phantom electrical issues and power drains. Owners find that fuses which should only be powered with the ignition in the "on" or "accessory" position remain live at all times, potentially draining the battery. "Every other fuse has 12V despite the truck being off for over 30 mins," noted one owner trying to install an accessory. This constant power can lead to a dead battery if a device is left plugged in or if there's an internal module malfunction.

Intermittent problems are also common. A truck may start and run fine, then die unexpectedly after moving a short distance, or it may refuse to start until it has sat for an extended period. These gremlins are often tied to failing control modules or bad connections that temporarily reset. Owners have also reported using a battery disconnect as a troubleshooting step for unrelated issues, like infotainment glitches, highlighting the electrical system's interconnected nature.

Most Likely Cause

Based on owner data, the most likely cause of battery and no-start issues in this model is damaged wiring or a faulty connection in the critical circuits between the battery, ignition system, and control modules. Specifically, owners have pinpointed problems with wires leading to the Fuel Pump Control Module (FPCM) and issues with constant power where there shouldn't be any. The fuel system is electrically controlled, and damage to its wiring harness can create a cascade of failures. A short or open circuit in these wires can prevent the Powertrain Control Module (PCM) from engaging the starter relay or powering the fuel pump, resulting in a no-start condition even with a good battery and starter. This isn't a simple case of a worn-out battery; it's an electrical fault disrupting the vehicle's command and control network.

How to Diagnose

Diagnosing this issue requires a methodical approach and a few essential tools: a digital multimeter (DMM), a test light, and a wiring diagram for your specific 2020 Silverado. Start by verifying the basics. Use your multimeter to check the main battery voltage. It should read at least 12.4 volts with the truck off. Next, check for voltage drop by measuring across the battery terminals while a helper attempts to crank; a significant drop below 10 volts points to a weak battery or poor terminal connections.

If battery power is good, the next step is to check for command signals. Locate the starter relay in the under-hood fuse box. Use your wiring diagram to identify the control circuit pin. With the ignition turned to "start," use the test light or multimeter to see if the PCM is sending a ground signal to energize the relay. If there's no signal, the problem is upstream. This is where owner reports become crucial. Inspect the wiring harness, particularly around the Fuel Pump Control Module (FPCM) and along the frame rails, for any signs of chafing, corrosion, or damage. As one owner discovered, the fix was in the wiring: "Found some chaffed wires going to the fuel pump control module."

Finally, investigate parasitic drain. Set your multimeter to the amperage (10A) setting. Disconnect the negative battery terminal and connect the meter in series between the terminal and the battery post. With all doors closed and the truck asleep (wait 30+ minutes), the drain should be less than 50 milliamps (0.05A). A higher reading indicates something is staying on. To find it, pull fuses one by one while watching the ammeter; when the drain drops, you’ve found the culprit circuit.

Step-by-Step Fix

Important: Disconnect the negative battery terminal before beginning any electrical repair to prevent shorts or accidental airbag deployment.

1. Gather Information: Obtain a factory service manual or reliable wiring diagrams for your 2020 Silverado. Identify the locations of the FPCM, PCM, engine ground points, and the relevant fuse boxes.
2. Visual Inspection: Based on owner reports, thoroughly inspect the wiring harness leading to the Fuel Pump Control Module. Look for insulation worn through from rubbing on the frame or other components. Check all major engine and chassis ground connections for corrosion or looseness. Clean and tighten them.
3. Repair Damaged Wires: If you find chafed or broken wires, this is your likely fix. Carefully cut out the damaged section. Strip back the insulation on both ends. Use crimp connectors with heat-shrink tubing (preferably with adhesive lining) to splice in a new section of wire of the same gauge. Seal the repair thoroughly to prevent moisture ingress. As one owner shared: "Found some chaffed wires going to the fuel pump control module got those fixed."
4. Test the Control Module: If wiring appears intact, the FPCM or another control module itself may be faulty. With wiring diagrams, you can test for proper power, ground, and signal at the module connector. If inputs are good but outputs are not, the module may need replacement.
5. Check Fuse Box Integrity: For owners experiencing constant power on accessory fuses, the issue may be internal to the fuse box or a faulty ignition switch. Verify the switch is sending the correct signals. In some cases, a specialized fuse tap may be required for proper accessory installation without causing a drain.
6. Reconnect and Verify: Once repairs are made, reconnect the battery. Start the truck and verify the problem is resolved. Use your scan tool to check for any diagnostic trouble codes that may have been set.

Parts and Tools Needed

• Digital Multimeter (DMM): Essential for measuring voltage, resistance, and amperage.
• Test Light: A simple tool for checking for power and ground signals.
• Wire Crimping Tool and Heat Gun: For professional-grade wire repairs.
• Assorted Crimp Connectors and Heat-Shrink Tubing: Use correct gauge sizes.
• Replacement Wire: Stranded copper wire matching the OEM gauge (often 16- or 18-gauge for sensor/control circuits).
• Fuse Tester or Fuse Puller: For checking fuse box circuits.
• Factory Service Manual/Wiring Diagrams: Non-negotiable for accurate diagnosis. Helm Inc. publishes the official manuals.
• Scan Tool: A capable OBD2 scanner can help communicate with modules and read live data.

Real Owner Costs

The cost to fix these electrical issues varies wildly based on the root cause and who does the work.

• DIY Wire Repair: This is the most cost-effective solution if you find simple chafing. The cost is just for materials: a roll of wire, connectors, and heat shrink tubing, typically under $30. The value is in your diagnostic time and skill.
• Professional Diagnosis and Repair: If you take the truck to a shop, diagnosis alone can take 1-3 hours of labor at rates from $120-$180/hour. If the issue is a damaged harness, a shop may charge 2-5 hours for repair, totaling $240-$900+. If a control module like the FPCM needs replacement, the part can cost $150-$400, plus 1-2 hours of programming and installation labor.
• Dealer vs. Independent Shop: An owner noted that for some parts, the dealer was competitive: "Got a factory battery tray cheaper at the dealership compared to aftermarket at the parts store, same for the AGM battery." Always get quotes for both OEM and aftermarket parts.

Prevention

Preventing these electrical headaches involves proactive maintenance. Regularly inspect visible wiring harnesses, especially in areas where they pass through the firewall or near moving components. Use zip ties or loom tape to secure any loose wires and prevent chafing. Keep battery terminals clean and tight, and coat them with a corrosion inhibitor. When installing aftermarket accessories (lights, stereos, etc.), always use a proper fused connection and, if possible, a relay triggered by a verified ignition-switched circuit to avoid parasitic drains. One owner's project highlights the right way: "Ordered a wire kit with an isolator off of eBay" for a secondary battery, which protects the main starting system.

What Owners Say

Real experiences from CHEVROLET owners:

Success Stories

"Found some chaffed wires going to the fuel pump control module got those fixed then the truck wouldn’t do anything again no crank no start. I’ve checked power and grounds again with a multimeter and a power probe i have good power and ground at the fuel pump,starter,12.3v on battery i unplugged the fpcm to see if it would turn over and it still would not(to see if the fpcm was blown)." — Own-Yam-5606 (source)

"Photo just for attention… has anyone had any issues with their Apple CarPlay not connecting anymore? It’s a 19 model and my Apple CarPlay no longer works I’ve tried clearing everything and updating but nothing has worked even unplugging battery." — Ok_Negotiation_686 (source)

"It’s a 19 model and my Apple CarPlay no longer works I’ve tried clearing everything and updating but nothing has worked even unplugging battery. Wondered if anyone has had the same issue." — Ok_Negotiation_686 (source)

Owner Experiences

"Added a secondary battery in to my truck to run accessories. Got a factory battery tray cheaper at the dealership compared to aftermarket at the parts store, same for the AGM battery." — Sea_Guide_524 (source)

"Got a factory battery tray cheaper at the dealership compared to aftermarket at the parts store, same for the AGM battery. Ordered a wire kit with an isolator off of eBay." — Sea_Guide_524 (source)

"I was driving and my truck randomly lost engine power. Got it towed to a shop they checked grounds,power wires,relays,fuses about everything they could they said,so they told me they couldn’t fix it it has dash power,lights come on just won’t turn over,you can apply power to the starter and it’ll spin over.Anyway got it home and after it sat for a while it started and would die after driving a few feet." — Own-Yam-5606 (source)

FAQ

Q: How long does it take to diagnose a no-crank, no-start issue? A: For a skilled DIYer with the right tools, a basic diagnosis (checking battery, starter signal, and a visual inspection) can take 1-2 hours. Tracking down an intermittent fault or a single chafed wire in a large harness can take a full day or more. Professionals may be faster but will charge for every hour.

Q: Can I drive my Silverado if it has an intermittent no-start problem? A: Absolutely not. An intermittent no-start is a warning that a complete failure is imminent. You risk being stranded anywhere. If the problem is related to the fuel pump circuit, the engine could also stall while driving, causing a dangerous loss of power steering and brakes.

Q: Is this a common issue on the 2020 Silverado? A: While not a universal defect, our data shows multiple owners reporting similar electrical gremlins leading to no-start conditions. The complexity of modern vehicle electrical systems makes them susceptible to wiring issues from vibration, heat, and environmental exposure.

Q: DIY vs mechanic – what’s recommended for this fix? A: If you are comfortable with a multimeter, can follow a wiring diagram, and have patience, diagnosing and repairing a chafed wire is a very achievable DIY task. If the problem involves diagnosing a faulty control module or requires deep system scanning, a professional mechanic or auto-electrician with advanced diagnostic tools is highly recommended to save time and avoid misdiagnosis.

Q: Will disconnecting the battery reset the computer and fix my issue? A: It might, but only temporarily if the root cause is a physical fault like a broken wire. A battery disconnect can reboot the vehicle's computers and clear adaptive memory, which has helped some owners with glitches like non-responsive infotainment systems. As one owner noted, they tried "even unplugging battery" for a CarPlay issue. However, for a no-start caused by a wiring fault, it will not provide a permanent fix.

Q: My fuses all have constant power. Is this normal? A: No, it is not. Most fuse boxes have a mix of constant battery fuses (for memory, alarms) and switched ignition/accessory fuses. If many fuses are live with the key off, you may have a faulty ignition switch, a problem within the fuse box itself, or you may be misinterpreting the circuit. Careful testing with a diagram is needed.