heater fan

I have a 1990 honda civic. The heater/defroster fan has 4 speeds. The
first 2 do not work and the last 2 work intermitantly.n Sometimes when I
come to a stop or just slow down or let up on the gas the fan motor will
speed up. Also, it seems the hotter outside it gets the less the fan
works. Is this a motor replacement problem? If so, is there a link
somewhere that I can use to learn how to replace/repair it? Thanks,
Bill

 

Blower resistor. Remove glove box. Resistor is right in front of you in
heater duct.

About $40 new at the dealer. You can fix them yourself with resistor wire
if you know how to solder.

 

Probably not. First, check the blower resistor assembly. It's usually in the
blower box. At the low fan speeds it has to dissipate a lot of heat so they put
in the path of the air flow. Eventually those power resistor elements
deteriorate and open up. That's what causes the loss of some fan speeds.

The blower resistor on my '88 Prelude has one electrical connector on it and is
held in the blower box with two screws. Yours, like mine, probably has three
resistor elements.

 

Thank you for your replies. I have one quick question. Is there a way to
test the resistor to make sure thats what the problem is without buying
expensive equipment?
Thanks,
Bill

 

Yeah.

Pull it and have a look at it with your eyes. If any of the wires are
broken (split in two or more pieces), then it's bad.

 

============================

Yes, perform a resistance test on it. There will be three resistors,
probably, and the readings will be something like 3 Ohms, 8 Ohms, and 12
Ohms, or something like that. I don't have a schematic for a Civic, but
you just slip it our and look closely . . You'll probably see the
problem. Check that there isn't crud blocking the air from cooling it,
or corroded terminals inside the connector you have to slip off. Plastic
windshield cowl might be leaking water into resistor pack and corroding
it. 1st gen CR-v does that.

'Curly'

 

I finally replaced the blower resistor and the blower worked fine and all 4
speeds. But now I have another problem. The fan speeds up and slows down
and it is especially noticable on high. I can turn the fan completly off
and turn it back on high and it works good for a few seconds and slows
down. It also speeds up when I slow down or come to a stop. Seems to be
erratic. Is this a voltage regulator problem or alternator belt problems?
Or what? I am stumped!

 

could be a fan bearing. how old is the vehicle?

 

1990 honda civic 4 door 5 speed

 

How's your battery? Turn your headlights on, then compare brightness at
idle and at 2,000 rpm.

I suspect your battery is dying, or the cables are corroded/frayed/loose.
You just never noticed this until all the fan speeds worked again.

 

I had battery checked and it needed replacement. I did that and the heater
fan worked and then it started slowing down and not working at all. I
suspect the motor is going,,,do you? Is it hard to remove that??
Thanks,
Bill

 

It shouldn't be necessary to remove more of the dash. For what it's worth, the
service manual for my 1988 Prelude says:

Remove the battery negative terminal.

Remove the glove box and glove box frame.

Remove the heater duct (to the left of the blower).

Remove three mounting bolts holding the blower assembly.

Disconnect the wiring to the blower motor, resistor and recirculation control
motor.

Remove the blower assembly.

If you want to feel bad, remember that there are several people back in the
factory that can install one in less than 30 seconds.