Thomas Utz

Hi.

Just bought a 2001 DX 5 speed and the previous owner had actually wired a toggle switch to the blower motor directly. Well the switch got hot yesterday and pretty much just broke for lack of a better term. So I want to go through all the motions and find the problem to get it working as advertised.

The previous owner said it just stopped working on all speeds. The blower motor works when bypassing the whole rest of the circuit, so it's not a motor.

Ohmed out the resistor and tested the diode. Checked good.

Checked fuses. All looks good.

I haven't checked relays, but that's partly why I want to find a good schematic.

Was thinking of buying a Haynes or subscribing to Mitchell, but generally on these forums most say to check here before wasting money on those.

Thanks.

mikey1

you need to replace the resistor/transistor unit on the blower motor,

remove the kick panel under the dash on the passenger side,

follow the wires from your toggle switch to where they plug into a 4 pin wire connector,

the part you need to replace is where that 4 pin connector would normally plug in, right now it is probably unplugged,

i have the same problem and i too wired a toggle switch like that temporarily,

ezone

Unhack all hacked wiring.
Restore to "as built" condition.


Fix the original problem. Probably the blower power transistor as mikey1 said.

Thomas Utz

I ohmed that resistor yesterday and everything checked out ok. I was thinking it was that also. Could it still be the resistor even though it passed the ohm test?

CraigW

iTrader: (1)

You do utilize a transistor assembly correct ?

So No 3 set speeds fan control in DX ? continuously variable speed control...Yes ?

ezone

What ohm test is that?

None of my test equipment ever shows that on the display LOL

Did your service manual direct you to do a test similar to this?





I rarely ever use continuity testing as outlined in a shop manual because it doesn't account for load. Instead I rely heavily a wiring diagram to formulate my own dynamic testing on live, operating circuits.



Connect everything as Honda built it.
Turn on the fan, then connect one voltmeter lead to battery neg or chassis ground....now backprobe to test each of the two fat wires at the resistor. If one shows 12v, the other shows 0v, that means the transistor isn't providing the ground to the motor for some reason.

At this point, the image linked above would be included a next step in testing.
Yes it can still be bad.
Did you take it apart and check if the internal TCO fuse is open?

ezone

Waay oversimplified diagram that may not match anything on your actual car (was labeled as for a CRV)

ezone

Thomas Utz

Awesome! This helps tremendously. Yeah so the test I did yesterday was off of a website somewhere. Ohmed pins 3 and 4 on resistor/transistor and got a little over 1500 ohms. Ran a diode test on pins 2 and 4 and and had current drop one way, flipped the leads and nothing the that way. I think I'm going to wire everything back up the way it is supposed to be and try backpinning the resistor connector. Thanks!

ezone

Q&D: Remove and open the transistor assembly.

Check as follows:








If you have open circuit (blown like a fuse) across the terminals shown, it's bad.
If the TCO is not open, you will see zero ohms or continuity


EDIT:: I might jumper across the TCO terminals just to make sure the fan will operate correctly, and the rest of the system is capable of controlling it as designed.
I have a few of these I've turned into test units to save time in diagnosis.


Replace the cabin filter set if they are dirty. The transistors heat sink depends on good airflow to keep it from overheating.

mikey1

just wanted to update this thread....

i had a faulty transistor on my blower motor last fall, i fixed it temporarily by installing a toggle switch between two of the transistor pins/wires,

this worked fine over the winter with the heat, the toggle switch would turn the blower to max speed or off with no in between,

hot weather came and i found out this setup will not work with the air conditioning....it will not turn the A/C on

today i went to the electronics store and for ONE DOLLAR i bought 10 resistors (although only needed one),

i followed the tutorial below, and to my amazement it actually worked....blower motor now works 100% at all speeds back to normal....

https://honda-tech.com/forums/honda-...istor-2041582/




..

ezone

I soldered jumper wires and an ATO fuse into my test units just to make them work.
FREE using stuff laying in the toolbox drawer LOL

CraigW

iTrader: (1)

The part jumpered/open component is a 114 degree C TCO thermal fuse, and not a carbon resistor.