Hey guys!

I'm having a similar problem. I just bought a 91 Honda civic hatchback standard model and I'm not getting any heat. Initially, I tried turning on the heat, but the fan wouldn't blow period. I've replaced the blower motor, and now, the fan does work, but only on the highest setting. When one tries to moderate the speed, it remains on the highest setting. I replaced the resistor on the blower unit because I found some other posts that stated that it might be that. Still though, it only works on its highest setting. I'm running out of ideas to fix the problem. I've also heard from another person that it might be the climate control unit, but I want to be a bit more certain. Since the resistor was costly, I'm trying to be frugal with purchasing parts. If you have any suggestions, I would really appreciate it!

 

In the engine bay up against the firewall there's a little thing like a flap or valve where the coolant lines run into the firewall into the car. I've heard of people not having the arm connected to it therefor it wouldn't open. Does your climate control work as far as blowing where you want it to or is it stuck in one setting?

 

1. With the ignition OFF, dis-connect the connector from the back of the fan switch (the actual **** you turn for fan speed).

2. Turn the ignition to ON(II).

3. Measure voltage from blue/yellow, blue/white, blue (respectively) to body ground.

Is there battery voltage on any of those wires?

NO- repair the open in the wire with no voltage between the speed switch and the resistor

YES- Measure continuity (Ohms) from the black wire to body ground

Is there continuity?

NO- Repair the open in that wire between the switch and ground or it's a poor ground.

YES- Replace the switch

So, in conclusion, if you have battery voltage on blue/yellow, blue/white, blue and there is continuity on the black wire then you need a new switch.

 

A proper voltage/continuity check will help, but since you replaced the resistor pack then the only parts left are the wires going from the switch and the switch itself.
did you replace the resistor with a NEW one or a used one that was said to be good? This is a very common problem to have the resistor go bad so if you picked up a used one, it wouldn't be much of a surprise if it were bad.



-_-
The flap you are talking about adjusts how much hot water goes into the heater core. It has nothing to do with the blower speeds.
If you would have read the post, you would see that he has blower issues where it's stuck on one speed.

 

Yes. It does blow where I want to it to (for instant, if I want to open and close the flap for the blower motor, I can with the climate control unit.

Ok, I have to admit that I'm kind of a newbie with cars, so I'm not quite sure how I would go about measuring the voltage. I do own a multimeter, though I don't know how to use it. I'll try and take your advice step by step and see if I can figure it out.

The resistor was brand new at the auto parts store. Yeah....That was a mistake (spent $40 and didn't get the problem fixed. Bummer!)






As a final note of interest, I tried using a different switch today (to adjust the speed of the fan), yet that didn't change anything. Luckily, my dad owns an 89 Honda Civic Hatchback DX, so the parts are, for the most part, interchangeable. Luckily, I didn't have to waste any money there.

The last two things I suspect might be at fault are the relay (not quite sure of the technical term, but I heard from some people that it dealt with the blower motor), or the wires (someone said there might be a short in one of the wires.)

Otherwise, any other ideas?

Thanks guys!

 

If the switch you used to test is known to be good then you need to test those wires.

To test voltage- Turn the multi-meter to V (volts) then touch the black lead to body ground and the red lead to the wire you're wanting to test.

To test for continuity- Turn the multi-meter to ohms then touch the black lead to body ground and the red lead to wire you want to test.

NOTES:

1. Body ground is any bare part of the chassis that you can touch with the black lead. Easiest thing to do is find wires (usually black) bolted to the chassis, that's your body ground. I usually use a clip on the end of the black lead.

2. There's no character on my keyboard for ohms but, it looks like a Greek symbol. Kinda like half an O with feet.

3. ***NEVER, EVER TEST A LIVE CIRCUIT FOR CONTINUITY (OHMS)*** You're only testing the ground circuit (black wire) so you'll be fine.

 

Alright then, I just have a few more questions (please bear with me. I'm really multi-tester illiterate.)

1. When testing the wires, do I have to cut into the rubber to expose the wires or can I just plug in the red cables into the bonded-together adapter?

2. For voltage, my multimeter has DCV and ACV. Which one do I want to measure and what should I put the setting at (at 200, 2000, 20, etc...)

3. So if I'm testing for continuity, I have to make sure that the battery is unplugged in order to test it. I'm not quite sure by what you mean by not testing a live circuit.

Thanks again for bearing with me!

 

I'm not sure if I did this correctly, but I tested the DCV for the cable that plugs into the blower motor. I found that it supplied around 12V (which I'm fairly certain is good.) However, when I tested the cable that plugs into the resistor, I couldn't get any readings. Now I'm not sure if that means that I was doing something incorrectly, but I plugged into the black wire and all other three ones, so I would assume that I should've gotten some reading, right? Does this mean that my blower motor resistor is not getting power then?

 

Each wire going into the resistor pack should carry ground from the switch at some time depending on what you have the switch set to.

Car ignition should be off.
Disconnect the plug that goes to the resistor pack.
Set your multimeter to OHMS.
Touch the two leads together - the reading you get by doing that is what you will be looking for in the following tests.

Connect black probe to chassis ground.
Put red probe into any wire in the connector (the wire harness connector and not the resistor pack itself).
*** if the red probe tip is too big to fit into the connector, you can strip the ends off some spare wire and wrap one side around the probe and use the the other end of the wire into the connector.***
Turn the fan switch through all positions slowly and check the meter for the reading you got earlier.
Repeat this on all 4 of the connector wires.
Each wire should give the reading, but at different settings on the switch.


The blue wire with black stripe should definitely give you the reading. This is the highest speed setting #4 on your switch which is working.
Do that wire first to make sure your setup is good.

The other 3 wires are
Blue - setting #1 (lowest setting)
Blue/white - #2
Blue/yellow - #3

 

Hey Guys!

I've been a little busy as of late, so I haven't been able to keep this post updated on the issue.

With that said, I've checked the wires that connect to the blower motor, and that supplies about 12 volts. But when I checked the wire that connected into the resistor, I got nothing. Furthermore, when I tested the wire that connects into the switch on the climate control unit, I got nothing there either. This leads me to believe I have to tear into the carpet (which I haven't done before), and try and fine a break in one of the wires. So my question is do I just have to focus on the passenger side area and find the wire that runs from the switch to the resistor, or am I looking for a certain wire that is on the driver's side (Does the wire from the switch or resistor run to the fuse box that supplies power? I'm assuming but just want to double check.)

Thanks guys for the help!

 

Hey guys!

Just to provide some closure to this post, I could not figure out the problem because it is SUPER cold here in Minnesota. All the signs point to me having to rip off the carpet and the dash to access the wires (which I can't currently do). I had a friend of mine just come on over and wire a switch though so I can operate the heat on high or off. That should do me just fine until the summer comes. When that happens, I'm ordering some new carpet (because the old stuff is in terrible condition) and make it a priority to deal with the issue then.

Thanks for all the help though! I appreciate it!

 

How did the OHM testing go?

 

Thanks for all those who posted helpful information here on this thread. I learned alot about what is what in the heating system in this car. I used the information here and in another thread to figure out that my resistor is good, the blower motor is good, but I may have a problem with ground. I also put in a new switch because the switch that was in there was getting really hard to move when the car was cold.

Thanks again!

 

This thread helped me, too. Good info.