Car is a 2000 Civic EX.

For some reason my HVAC only works on full blast. Anything other than that, nothing comes out. All buttons work/light up (circulation,AC,rear defroster) when pressed. Any solutions?

edit:

Now a second problem arises.

Nothing works or lights up on the buttons, including all fan speeds + defrost when weather is extremely cold. Solutions?


Modified by RyanJC at 4:06 PM 12/11/2006


Modified by RyanJC at 10:13 PM 12/24/2007

 

Bump, anyone? Checked the fuses, they're fine.

 

Sounds like something would either be wrong with the selector element at the back of the ****, or an electrical problem, like in the relay or the blower motor itself.

 

fan speed resistor, when to put the control to full blast you hear a relay click, it bypasses the resistor and the fan works, easy fix

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sicones &raquo;</TD></TR><TR><TD CLASS="quote">fan speed resistor, when to put the control to full blast you hear a relay click, it bypasses the resistor and the fan works, easy fix</TD></TR></TABLE>

I think this is the problem! How much do the fan speed resistors run for? Where is the resistor located at?

 

OK, now the HVAC does not work at all when the weather is extremely cold. Nothing lights up and all fan speeds do not work. Is this still a blower resistor problem or something else?

Driving in 30 degree weather with no heat FTL

 

I'd still start with the blower motor power transister.. But I'd check to make sure the blower motor still works first..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PnX-R &raquo;</TD></TR><TR><TD CLASS="quote">I'd still start with the blower motor power transister.. But I'd check to make sure the blower motor still works first.. </TD></TR></TABLE>

i had a similar problem and it was from when i installed my head unit. i didn't get the plug all the way back into the switch.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PnX-R &raquo;</TD></TR><TR><TD CLASS="quote">I'd still start with the blower motor power transister.. But I'd check to make sure the blower motor still works first.. </TD></TR></TABLE>

Well I know for sure the power transistor needs to be replaced but it still doesn't explain why HVAC doesn't work in cold weather. Blower motor is fine.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 96ls &raquo;</TD></TR><TR><TD CLASS="quote">i had a similar problem and it was from when i installed my head unit. i didn't get the plug all the way back into the switch.</TD></TR></TABLE>

This could be it. I had the stereo pulled out to get a serial number from the back. But that was back in early August. What exactly was your problem and how did you fix it?

Thanks for the reply guys.

 

my prob was it just worked on defrost. nothing else. all i had to do was plug the connector in all the way and it fixed it.

 

Today I got a new power transistor. Installed it in, still the same problem. Only high-speed works. Is there any way to test my old power transistor if it's actually broken? I have a multimeter.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RyanJC &raquo;</TD></TR><TR><TD CLASS="quote">Well I know for sure the power transistor needs to be replaced but it still doesn't explain why HVAC doesn't work in cold weather.</TD></TR></TABLE>I wouldn't be so quick to say that. You know that metal contracts as it cools...

(It's a possibility.)

 

Bump,

I still haven't gotten this fixed after a year. Anyone have any other possible solutions? I hoping the two problems are related and that finding a solution will fix both problems.

 

make sure u have the resistor block plugged in the rite way, cause the way it works is when u have it on full blast it gives the motor 12V and on the other speeds it runs it through a series of resistors, if u plug it in the wrong way i have found that your problem still exists.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blueEM1 &raquo;</TD></TR><TR><TD CLASS="quote">make sure u have the resistor block plugged in the rite way, cause the way it works is when u have it on full blast it gives the motor 12V and on the other speeds it runs it through a series of resistors, if u plug it in the wrong way i have found that your problem still exists.</TD></TR></TABLE>

There is only one way to plug in the power transistor.