HVAC blower problem - 2005 Tacoma 2.7L

Hi all. I had a new problem develop today with my HVAC blower. It does not blow air on any speed setting.

I pulled the blower motor and applied 12v directly to the terminals on the blower motor and it spun up fine. Then I put a voltmeter on the plug itself. It is giving me 12v reading on all speed settings other than off. Thinking this is odd, I ran a couple of wires off the power plug for the blower motor and put a 12V test bulb on the wires to see if it would light up, and it didn't.

This is telling me that I'm getting voltage to the blower, but no amperage. I checked the fuses (all the 10 amp & 15 amp) but the owners manual doesn't tell me for certain which one controls the blower, and I didn't have any spares for the 50A fuses (if those are the ones that control the blower). However, I'm not having any other electric issues, and in fact when I turn on the A/C the compressor is kicking in even though the blower isn't and both the A/C and Recirc lights on the HVAC control panel illuminate when pressed.

I'm thinking possibly its the resistor for the blower (I've read where that can be a problem), but what I've read also tells me that even if the resistor goes bad, the blower should work on the highest speed setting, and mine doesn't even work there. I'm hesitant to just replace the resistor since (A) it is going to be tough to get out and (B) it's a $35 part that I don't know for sure is bad.

I'm really perplexed. Any one have any ideas?

Andy

 

This might help. You can download the full manual from . According to the schematic, the blower should work on the hi setting even if the resistor is bad. Have you checked that the heater relay is good. It looks like it's the motor's path to ground.

 

Thanks for the input. Yesterday I ordered both a relay and the blower resistor. I did pull the relay last night. It was in the socket so tight I ended up ripping the cover off the relay, and afterwards had to literally pry the rest of the relay out of the socket with the flat end of a screwdriver.

At any rate, using the test procedure in the manual the relay seems to test okay. I put 12 volts on it and heard it click. In all honesty though I don't have a good grasp of Ohm testing with a multimeter. All I seem to get is a 1 or 0 on the display. I'm not real clear on which scale to use. But, since I tore the top off the darn thing I decided to go ahead and replace it anyway (only $12 bucks).

I'm really hoping it is the relay or the resistor because that's about as far as I can go on my own, and I've no doubt that if I need to have the dealer dig into it it'll start adding up to some serious bucks.

I'll report back once my parts are delivered.