heater blower does not work HELP COLD!!!

[fast2002]

my blower will not come on the fuse is good, could the heater switch coil which control the speed be bad? Is there a relay? I am not getting 12V to the fan.

1976 2002

thanks

[Gordon]

Dude,

You are about ready to tackle one of the suckiest jobs in 02 ownership. The dreaded heater box removal and refurbishment. If you haven't done it before, your heater fan and core probably haven't seen the light of day in 33 years. With the heater box out, make sure you take your heater core to your local radiator shop for them to core it out and check for leaks.

http://www.bmw2002faq.com/content/view/73/32/

G-Man

[Mike Self]

1. connect a voltmeter to the two blower motor terminals and turn the blower switch on. See if you get +12v; if not, leave the + jumper wire on the motor and clip the - wire to a good ground. If you now have +12v, your motor's ground wire is bad or the motor itself is.

2. Turn the blower switch to high, and then feel the fuse. If it's warm, the motor is getting current but not turning.

3. If you have voltage, try turning the fan by hand (or with a thin screwdriver). See if you can get it to move even a little bit by itself, then drip a little oil onto the armature bearing that's visible at the upper end of the motor. Keep persuading and as the oil penetrates, it just might start working again.

If the above doesn't work, it might be heater overhaul time. Lotsa posts and FAQs on the procedure, and it's not that bad unless you have A/C. Then it's difficult, but not impossible.

Good luck

mike

[roadhog0]

Do you have AC? If so try turning your AC knob one direction or the other. I know that I have to have my AC knob turned all the way to the left to get my heater fan to work.

[NMDerek]

OMG , I've been putting this off for 2 years. just did it but only have high speed but at least I'll have heat so i can drive in Oct and beyond.

So now i have 2 old boxes.

Wasn't there some guy selling refurbs? they were sweet.

Motors don't work on the both of them but i will try a refurb on the one that came out and see if i can getter done.

[biltwok2]

Not to steal the post, but this question might be helpful. Once the heater box is out of the car, can someone describe the procedure to test the 3 fan speeds using an external power source? Hopefully this also evaluates the dash switch.

[Swiftus]

Bench testing the box is pretty straight forward. If you have the box all put together in front of you, with the fan on top and the 4 electrical contacts facing you, this is the pattern (I believe).

Ground (Negative or Black) will be the furthest contact to the right, middle row, furthest to the center . . .

Full power or HIGH will be the furthest to the left, middle row, furthest to the outside . . .

MEDIUM will be the top contact, center column

LOW will be the bottom contact, center column

A few more tips...

Make sure that your power source is capable of puuting out a few amps of power.

Try to test with a 5 amp fuse in line with the power lead (This will hopefully stop you from burning up your freshly restored box)

+12 V in a car is actually and voltage between ~11.5 and 13.5, so an output in the range is fine and you need not worry about having exactly +12 V.

Good Luck! When you are finished rebuilding the box, you will simply be amazed at how well the heat in these old cars actually works! Dudley and I fixed his heat on a night with temps in the mid 30s, and the temp in the car had to be around 80 or 85 . . . without foggy windows!!!

[NMDerek]

Do they make a device that plugs in to a 110 outlet , or is the battery the only option to test the fan??

tia Derek

[TobyB]

I am not getting 12V to the fan.

if that's true, get 12v to the fan. Then you'll be good.

My fan broke loose years ago, so I just use the vent window these days.

And I only get heat when I'm going fast enough to keep it from freezing/ fogging up.

Might I suggest gloves and a hat?

t

20f today...

[ArdenK]

Might I suggest gloves and a hat?

Don't forget an ice scraper to remove the frost on the inside of the windows!

Joking aside, try hooking up the blower with jumpers. If it works, install a temporary switch until you have time to rebuild your heater box or find a good replacement to switch out.

Good Luck!

[Scott Sislane]

It's not that big of a deal to replace the motor. It's an 8 hour job to remove the box, replace the motor, and re-install the box, if you're taking you're time... and well worth the 8 hours. Just make sure to close the incoming coolant (slide the heat lever to the off position) line before you pull it out, or you'll have coolant all over the inside of your car.

[biltwok2]

In Pic #3, there is a pigtail hanging down just in back of the dash switch. I believe this is a T connection, and is the power source for the fan. In order to bench test 3 fan speeds thru the switch, how does one go about connecting 12v to the 2 connectors in the fitting? Ground is somewhere else, correct?

[BillWilliams]

I bought a small AC/DC converter from Radio SHack that makes testing most things DC easy. It has two terminals for hooking wires to that can be used for this test.

It also has a cigarette lighter for powering devices with this type of connection or charging stuff in your garage that you would normally charge in the car.

I am not familiar with the T connector you reference

[Scott Sislane]

In Pic #3, there is a pigtail hanging down just in back of the dash switch. I believe this is a T connection, and is the power source for the fan. In order to bench test 3 fan speeds thru the switch, how does one go about connecting 12v to the 2 connectors in the fitting? Ground is somewhere else, correct?

Yes, I believe that is where the 12V feeds into the unit. I recall on all 3 I did, just plugging the box in there when I was done, to test it, before putting all back together. Cannot recall the wiring scheme though.

Scott

[BillWilliams]

Bill from Cleveland and I just had a conversation about this. Just to ensure we are all clear, the four slider unit and the three slider unit have different wiring connections i.e. the T connector to the switch and lights.

For clarification, the 3 slider units fan speed control is a knob on the dash and those controls are not lit. The the fan speed control for the four slider unit is on the right hand slider unit and both slider units are lit.