So I have a 1999 LX and the heat was working, I shut the car off, got back in and now the heater will not turn on at all - no hot air, no cold air, no ac, turning the switch does nothing no matter what setting the air is on.

Is there any way to test to see if it's an issue with the heater blower motor relay, or whether its the actual blower itself? Any tests to isolate a single part that may be faulty so I'm not just replacing things hoping that one of them will eventually make it work again? I've only checked the fuses and so far they all look good.

Thanks in advance for any assistance.

 

Do you have power and ground at the blower motor?

 

Check a couple things:

Check for any burnt out fuses
Check the resistor

If those check out good you can check the blower motor by hooking it up to a 12 v source.

I suspect the resistor.

Good luck

 

I had this happen to me once except my car was a 94 accord. I came back to the car just as you stated and nothing no air flow whatsoever.

Turns out it was the blower motor and there is a trick and simple fix, assuming your blower motor is under the glove box, locate it and slap the bottom of the motor it SHOULD work, that is the easiest temporary fix.

GL

I have a question does your motor make a noise as if something is in it?

 

I don't think your car has a blower motor relay. It may be the blower resistor, which is located at the bottom of the blower unit. It is held in with 2 Philips screws. To test it, unplug the electrical connector, then use a multimeter to check the resistance between the number 1 and 5 terminals on the resistor. I don't remember the exact specs. for your car; but, I believe it should be between 2 to 3 or 3.5 ohms.

 

LOL. Mine did and it was driving me crazy. I took out the cabin filters and reached around in the filter chamber and in the blower and pulled out some leaves. Put the filters back in, started it up and it still made the noise. I was like wtf?! I ended up take the blower out and there was one little part of a leaf that was about the size of a quarter. Everything's fine now.

If the noise is speed consistent then it's probably just debris but, it could be the blower motor wearing out (not very likely tho).

 

Hey guys thanks for the info so far, this is great stuff. I've been looking everywhere for my damn multimeter and I can't find it so I have to pick up another. Ill post back with more info when I get a hold of one.

 

A resistor burned out on my car one time and when I pulled it out and inspected it, there were obvious burned out electrical components on it.

When my resistor burned out only one setting didn't work.

For example, blower setting 1,2, 4 worked, but 3 was burned out.

I have also had to replace the blower motor and that is also an easy fix.

Pull the glove box door and then pull the blower motor and check the blower motor by hooking up to an altenate 12 volt source.

when you replace the blower motor make sure the polarization is not reversed.

If the positive and ground wires are reversed the direction the blower motor rotates reverses.

 

sometimes the bearin goes out too.

then it will wobble while it rotates.

 

Just like GJDM said about the resistor for the blower motor speed. Also, if it was the resistor, it would be only one out of 4 speed for example that would not be working, so thats how you tell if it's the resistor or not.

If there's no power at all in all speeds, I'd say it's an electrical issue that isn't sending power or getting a good ground.