Heater only working on high. New power transitor
 

The heater only works when it is set to high. I was looking for solutions online and it was basically pointing. To the power transistor. I bought a new one and installed it but nothing. When the heater is set to blow on high it takes a second then the relay clicks and then the blower turns on. I won't turn on on any other setting.
It a 99 civic lx. With brand new power transistor.
Any help please

Re: Heater only working on high. New power transitor
 

There is a high speed relay for max speed, and a power transistor for all slower speeds.

The high speed relay must be working (duh), and you have a new power transistor.

So the problem must be either the wiring or the HVAC control head (process of elimination).
Wire diagram and a volt/ohm meter?
No silver bullet here unless you can find someone with an identical car to swap HVAC controls with as a test.

Re: Heater only working on high. New power transitor
 

I think I had that same problem 3 years ago when I bought my car....

Took the switch apart and sprayed it out and it still works perfectly 3 years later..

hope this helps...

https://www.civicforums.com/forums/1...itch-free.html