jmwill90

Alright, here is the issue. A few months ago I hydrolocked my engine in a flash flood. It's a 1999 Honda Civic DX. Pulled plugs, got water out, got car to crank, drained oil, drained transmission fluid. Transmission fluid was fine so replaced, changed oil until was no longer milky looking. Only thing I had to do from there was replace the ECU because it had gotten wet and car was stuck in "limp mode". New ECU fixed the problem. After all of that the A/C would cut in and out but didn't really bother me because I never use the A/C. Winter is on it's way and my heater only blows cold air. A/C and heat worked fine before all of this. From the above information/history can anyone give me some places to start to fix the heater.

juan_p__m

sounds the blend door at the heatercore/a/c evaporator is not working, the 99 has electric controls unlike the early 6th gen, sounds as if you have to get out the multimeter and test the hvac controls, the air mix control motor, and the mode control motor to find which is faulty, good luck

hondaenslaved2

Start the car and turn on full heat. After the car has been running for like 5 minutes, "carefully" touch both inlet and outlet heater hoses (going to the heater core). They should BOTH be approximately the same temperature; the inlet hose being very warm/hot and the outlet being only slightly cooler. If the inlet is hot and the outlet cold you have a clogged heater core. If they are both cold check the heater valve. Might be rusted shut........ verify the heater valve arm moves as somebody rotates the temp switch inside the car.

jmwill90

Thanks for the responses. I haven't had time due to school and work to try these tests. I'll post results/concerns later on this week.

n8marsh

coolant is full?