Question: RE 2002 Civic I had the driver and passenger side airbags serviced on recall two weeks ago. It got cold this week and I find the heater blows but no heat. Is there a connection between the dash board airbag service (e.g. disconnected switch?) and the current "no heat" problem?

 

absolutely not unless they drained your coolant fluid. make sure your fluid is topped off. and make sure there isn't air in your cooling system by purging it otherwise it could be something worse like your head gaskit which was a common problem with the 01-05 civic. does it blow hot when the car is moving then stop when the car is stopped ???

 

+1 the first thing to check when the air blows but not hot is the coolant level, especially if as itburns said, it gets hot when you drive but cold again at idle. Check the level in the radiator itself, not just the white plastic tank. The radiator should be full to the top. The engine must be cold before removing the radiator cap-- that warning label is one that actually should be heeded.

Also if the thermostat is stuck open, the engine will not warm up, thus you get little to no heat. If this is happening, the gauge on the dash never moves off of cold.

If it's not either of those, you should check that the water valve on the firewall moves from closed to open (push pull cable moves a lever on the valve) when you turn the dial from cold to hot. I think this is electric on your model, so the key has to be turned on.

That last one may have something to do with replacing the passenger's airbag, but it is on the other side of the car so it seems unlikely.

 

I will check those items. The head gasket was replaced 24 months ago and the thermostat six months ago following an overheating incident. All has worked well since then. The gauge says normal warm not hot. It blows cold all the time. I will get back to you two with my findings. Thanks!