Heater blower not blowing

[rbirling]

I'm having an intermittent problem with my heater fan not blowing. This isn't the "only blows on high" problem. The dealer says to replace the motor and transistor, to the tune of about $700. From the symptoms, this doesn't sound like the transistor, from what I found using a search here. Also, sometimes, when I hit a speed bump, it kicks on, like it's a loose connection somewhere. Anyone got some insight into this one? Thanks a lot.

 

[Briank]

Hi Bob

Normally the problem is with the control board but if it comes on after hitting a bump then having a loose connection or bad blower motor is plausible.
Check the 3 connectors on the blower module behind the spare tire. If it always works when you turn the fan speed to high it’s not the blower motor.

 

[rbirling]

Hi Bob

Check the 3 connectors on the blower module behind the spare tire. If it always works when you turn the fan speed to high it’s not the blower motor.

Thanks Brian. That's what I was thinking. It doesn't blow even on high, so I am sure it's not the transistor. I'd planned to debug this myself, but then dropped it off to have the A/C diagnosed, which they can't do unless this kicks back in....

 

[pilotstephen]

My blower motor is intermittently weak and strong. Ive noticed that bumps in the road do have an effect. Ive also noticed that on occasion wiggling the wire thats visible behind the spare tire that goes to the blower motor, sometimes temporarily fixes the problem. I think in my case at least its just a loose connection somewhere.

 

[pilotstephen]

My blower motor is intermittently weak and strong. Ive noticed that bumps in the road do have an effect. Ive also noticed that on occasion wiggling the wire thats visible behind the spare tire that goes to the blower motor, sometimes temporarily fixes the problem. I think in my case at least its just a loose connection somewhere.

 

[Briank]

I would let them put in a new blower motor. With that done they can run the AC and the $200 cost of the power transistor if its not bad can go for other repairs.

 

[Ojas]

Hey Bob. Did you have a chance to check the relay box under the hood?

I had a similar issue - intermittent blower that sometimes worked after hitting a little bump. I replaced the blower motor, transistor, climate control board and still had intermittent blower. By dumb luck, I was messing around under the hood and noticed that when I wiggled the relay box around just right, the blower worked. I found a bad connection on the "blower relay" in "sub relay box A" (diagram on service manual page 23-10). You might want to check "blower high relay" as well.

Also, the troubleshooting chart for the blower motor (starting on service manual page 22-40) is very helpful. The dealer should have been able to "hotwire" the blower motor to diagnose your A/C issue.

 

[rbirling]

Hey Bob. Did you have a chance to check the relay box under the hood?

I had a similar issue - intermittent blower that sometimes worked after hitting a little bump. I replaced the blower motor, transistor, climate control board and still had intermittent blower. By dumb luck, I was messing around under the hood and noticed that when I wiggled the relay box around just right, the blower worked. I found a bad connection on the "blower relay" in "sub relay box A" (diagram on service manual page 23-10). You might want to check "blower high relay" as well.

Also, the troubleshooting chart for the blower motor (starting on service manual page 22-40) is very helpful. The dealer should have been able to "hotwire" the blower motor to diagnose your A/C issue.

I never got around to checking this after talking to you. I didn't forget your advice. Now I wish I'd taken care of this before dropping my car off. But I've had enough A/C repairs that I didn't want to put it off. I just looked at the wiring diagram and the relay, a bad connection, or the motor itself seem to be the only possible culprilts. Hopefully, they've gotten it working and I won't have to explain to them how to use the troubleshooting chart.

 

[rbirling]

I actually got around to removing the blower motor last weekend and debugging this. It seemed like it would be a loose wire, when I wiggled the blower motor wire, it would go on and off. But the wires were good. Then I dissassembled the motor itself. It was full of crud, mostly filings from the motor brushes, I think. I cleaned it all out with a toothbrush, reassembled it and it works perfectly now. I saved $700, and hopefully am good to go for another 130000 miles. :biggrin:

 

[RueMasterLa]

I am having the same problem. Now my blower doesn't come at all. It was not having the common Power Transitor symptoms.

Before I replace the Blower Motor, does anyone have any idea if disconnecting the Fresh-Air sensor would have any affect on the blower motor? (I removed the sensor due to contant interior humming noise)

 

[Briank]

I am having the same problem. Now my blower doesn't come at all. It was not having the common Power Transitor symptoms.

Before I replace the Blower Motor, does anyone have any idea if disconnecting the Fresh-Air sensor would have any affect on the blower motor? (I removed the sensor due to contant interior humming noise)

No it has no effect.

 

[rbirling]

If you replace the blower motor, send me the old one. :smile:

I am having the same problem. Now my blower doesn't come at all. It was not having the common Power Transitor symptoms.

Before I replace the Blower Motor, does anyone have any idea if disconnecting the Fresh-Air sensor would have any affect on the blower motor? (I removed the sensor due to contant interior humming noise)

 

[Jett]

I am having the same problem- my heater fan only comes on intermittently, usually when I hit a bump. (I have already had the CCU repaired by Briank.) Although I don't have the "blower motor only blows on high" problem, below is a link to Acura TSB 92-007 which shows the power transistor and blower motor. (It is located under the hood in the center behind the spare tire holder.) I will be checking the wiring connections, relays, power transistor, and blower motor.

http://www.nsxprime.com/FAQ/Reference/tsb/tsb-92-007.gif

Note: Blower motor part # 79310-SL0-A01 has been superseded by part # 79310-SL0-A02

Troubleshooting so far: Rapping on the blower motor case has no effect.

 

[Jett]

Problem Solved

The problem turned out to be one of the two relays in the circuit. Had the relay replaced ($40.97 for the relay, plus labor for troubleshooting). Problem solved - it is blowing fine now.