help_outline Skip to main content

6.3

heater blower test
Author Last Post
I find if I have the wire harness that runs along the bottom of the dash tucked out of the way there is 'just' enough
Mike, thanks! Well it was dead. I pulled everything and it was trashed. Waiting for the fan motor to arrive and heater core to come back from radiator shop.
The hardest part was getting the unit to slide over the transmission tunnel. Half an inch would make it so much easier. I’m tempted to hammer the tunnel flat😈

jim
James - if you see in the picture the red wire clip --that is direct to the blower motor B+ positive. The Black wire clip is direct to blower motor ground- negative. the remaining two pins are to the blower motor resistor low and medium fan. You can connect the B+ positive to either of these two pins to test the blower motor resistor.

Sorry this took so long and hope this will tell you that indeed your blower motor is ok.

The second picture is the blower motor in operation with the two jumpers, 12v supplied.

Best, mpmorris

Hi Michael
Any progress ?

jim
Thanks


jim
James -I am back in town and will have a look this weekend as I have to move storage -again. Will get back to you.

mpm
Thanks for getting back. I'll keep playing with it. If I come up with any bright ideas I'll post them.


jim

oh darn -really getting forgetful. I moved two exposed heater assemblies into storage before I left for Kentucky last week never pinching my brain that there was stored memory at my frontal lobe to remind me that I had made a commitment -so sorry james. I do not know how to apologize.

basically, you have to supply power after the resister to the motor- I just do not recall if the resistor, which is inside the case, can be removed externally or thus necessitating the removal of the box  -I recall there are two mounting screws at the 4-pin plug -but I am thinking it cannot be removed -maybe the right defrost vent -but that in itself is problematic. --so sorry james.

mpm
Hi Mike,
Did you have chance to devise a test?

jim
Thanks Art and Mike

jim
Hi Jim -- I have a heater box laying out and will check and give you an exact test for blower resistor and motor. Looking at the schematic, you should be able to ground the brown at the 4-pin connector and apply voltage to either of the other pins. Grounding the case will not close the circuit -you have a power and ground only at the motor

mpm
Do you think grounding the fan case from under the cowl would work?

jim
Jim, as you know, I was a surgeon, not an auto-electrician, but I would have expected your test to be valid.  If you have power to the one terminal, that should work, but you also must have a valid earth.  I would be looking to ensure your earth on the fan hasn't failed before I started pulling the dash to bits.
I have and it didn't, so I was wondering if it's a valid test.


jim
Hi Art
Thanks. Do you know if bridging the wires in the connector would activate the fan?

jim
 

Jim,
Hope this is helpful.
Art

So I appear to have a dead heater blower. The fan turns freely. I have pulled a four pin plug from the control module. One wire is hot and three are not. If I bridge the hot wire to one of the other wires should the fan run?
If that is a valid test and it still doesn't run are there other tests to run before tearing in to the dash?
I am guessing that if there is power to that plug (when the key is on) and the fuse is intact, then is no other power issue.

jim
Return to Forum