Dedicated LVC Member
- Dec 10, 2005
- Reaction score
Hello! I just purchased an 02 LS. I read through most of these posted threads, but was looking for one about the heater not working. I see some about the A/C blowing hot, but nothing about the heat blowing cold. Could you point me in the right direction? I did figure out how to pull the codes, but I couldn't seem to google a list of what they meant! Thank you
Common causes for heater not working:
1. Tiny cracks in cooling system plastic parts that let air in. This air prevent circulation in the heater cores.
2. DCCV - both valves stuck closed.
3. Aux pump - Applies to V8s only. If you only get some heat at highway speeds, then probably your aux pump has failed.
4. Cooling system was not correctly bled after some work on it.
5. Someone put plugs in your heater hoses because they didn't want to replace a bad DCCV.
6. Your thermostat has failed open or is removed.
Less common causes:
1. DATC is bad.
2. air discharge temperature sensors are bad.
3. Cold air bypass door is stuck in bypass (only applies to gen I)