Heater problem
Thread Starter
Heel & Toe
Joined: Nov 2007
Posts: 15
Likes: 0
From: Sierra Vista AZ
Heater problem
Tried searching, but nothing matched my specific problem.
Here goes: I have no warm air available until the coolant temp reaches about 230 even when I switch the HVAC off auto mode and turn the temp all the way up to 90 with the A/C off. It's just cold air, then when it hits 230 it's blazing. Is this normal on C5s? Everything else I've driven at least blows somewhat warm air until the car warms all the way up. I don't think the thermostat would affect the heater would it? I tried a search of codes and I got U1096H and U1160H for HVAC which are communication malfunctions, I think. I cleared them and it didn't fix anything. It's about to start getting cool here and would like to fix this before I wish I had done it a week earlier. Any advice would help.
Here goes: I have no warm air available until the coolant temp reaches about 230 even when I switch the HVAC off auto mode and turn the temp all the way up to 90 with the A/C off. It's just cold air, then when it hits 230 it's blazing. Is this normal on C5s? Everything else I've driven at least blows somewhat warm air until the car warms all the way up. I don't think the thermostat would affect the heater would it? I tried a search of codes and I got U1096H and U1160H for HVAC which are communication malfunctions, I think. I cleared them and it didn't fix anything. It's about to start getting cool here and would like to fix this before I wish I had done it a week earlier. Any advice would help.
Tech Contributor
Joined: Jan 2007
Posts: 19,359
Likes: 1,127
From: Dyer, IN
Start by checking the coolant level. Also, check circulation through the heater core inlet and outlet hoses. With the car at operating temperature, and the heat on, they should both be hot to the touch. If the inlet is hot, and the outlet is cold, it could be the thermostat.
