Few things are more irritating than a nearly new truck that cools the passenger beautifully while the driver sweats. If that's you, don't let anyone sell you a can of refrigerant and send you on your way. On these trucks the system often isn't low at all.
What's actually going wrong
Inside the condenser (the radiator-looking part in front of the actual radiator), there's a block-off plate that routes refrigerant through all the cooling passes. On some trucks it was mispositioned at the factory. Hot refrigerant takes a shortcut, skips most of the fins, and leaves the condenser before it has cooled into a liquid. Result: weak AC, especially on the driver's side.
GM's bulletin PIT5767 (August 2020) first listed 2019-2020 trucks. The updated PIT5767A extends it to 2019-2021 Sierra 1500 and Silverado 1500, all engines and transmissions, but only Silao-built trucks.
How to tell if it's your truck
- Check the VIN. The 11th character is the assembly plant. A "G" means Silao. Other plants aren't covered by this bulletin.
- Driver vs. passenger. Set both sides to full cold and compare vent temps with a cheap kitchen thermometer. A clearly warmer driver side fits this problem.
- Pressures look low, but it's full. GM says techs see roughly 15-25 PSI on the low side and 140-160 PSI on the high side, which looks like a low charge. But a recover-and-weigh shows the system is full with no leaks.
- Both condenser lines are hot. The line going in and the line coming out of the condenser are both very hot, and the condenser fins are near outside air temperature. Normally the outlet is noticeably cooler.
Easy things to check first
- Cabin air filter. A clogged one makes all the vents weak. It's a cheap DIY swap.
- Debris in front of the condenser. Leaves, bugs and mud packed into the fins kill cooling. Rinse gently with a garden hose, not a pressure washer.
- Cooling fans. With the AC on, the electric fan(s) should run. No fan, poor cooling at idle.
- Blend door. If one side blows warm with the engine cold and hot alike and the AC pressures are normal, a blend door actuator can be the culprit instead.
What it costs
| Situation | Who does it | Likely cost |
|---|---|---|
| Truck still under GM bumper-to-bumper warranty | Chevy or GMC dealer | Usually $0, mention PIT5767A |
| Condenser replacement, Sierra 1500 (general) | Shop estimate | RepairPal: $736-$932 |
| Condenser replacement, 2023-2025 Sierra 1500 | Shop estimate | RepairPal: $1,093-$1,424 |
| Condenser replacement, 2014-2017 Sierra 1500 | Shop estimate | RepairPal: about $531-$701 |
| DIY | You plus a shop for evacuation and recharge | Part cost plus recovery and recharge |
GM's parts list for this bulletin calls for one condenser, part number 84537760. If you're out of warranty and shopping around, that number helps you compare apples to apples.
When to call a pro
If the quick checks don't fix it, have the system pressure-tested and the charge weighed. That's the step that separates "low on refrigerant" from "condenser bypassing." Topping off a full system with a store-bought can overcharges it, which makes cooling worse and stresses the compressor.
What to ask the shop or dealer
- "Is my truck a Silao build covered by PIT5767A?"
- "Did you recover and weigh the charge, or just read gauges?"
- "Are both condenser lines hot with the fins near ambient?"
- "Is this covered under my warranty?"
- "Does the quote include evacuation, recharge and a leak check?"
Is it worth fixing?
Absolutely. You'll be living with this truck through a lot of summers, and a condenser is a one-time fix. If you're still in warranty, it should cost you nothing but a morning at the dealer. If you're not, a new condenser is still far cheaper than replacing a compressor that got hurt by repeated overcharging.
More Sierra info lives on the GMC Sierra 1500 page. Transmission shudder too? See our Sierra 8-speed shudder guide. Prices checked October 14, 2026.
