Air conditioner fan stopped blowing 2001

Interior fan stopped working. I checked fuses their good . What to check/do next? 2001 model. Jeff

you didn't check the right one LOL there is a relay in the front fo the car called blower relay.... take your horn relay out and swap it for the blower relay see if the relay is bad.

that's the only way to check as they are black square fuse type you can look at them and tell if their blown like the colored ones.

if the fan works again then you need to buy a new one.... but.... put the new one in the horn spot since we hardly ever use our horns it will be nice and new if the old horn fails again.

the fuse box you want to look for is the one in the front of the car bolted to the top of the firewall on the passenger side next to the main fuse box you can miss it.

Do as Shawn suggests. If that doesn't fix the problem, first confirm that the CCU is working properly. Second, check to see if the fan operates in the maximum speed position. If it does, then the power transistor that controls the motor speed may have failed. If the fan does not work in the high speed position, then the problem is somewhere else.

I have attached the schematic for the blower to facilitate trouble shooting.


View attachment 125063

Still puzzled...Fan does not blow on high...
The MAIN 30 amp fuse the has 2 screws holding it in looks fine, could not get the horn fuse loose to swap with blower fuse.
The square black "fuses" are not labeled and don't seem to want to come loose either. ???? jeff

With the ignition key in the run position, do you get 12 v on the blue/red wire to the blower motor? If not, then the fuse is bad or the blower relay has failed or you have a bad connection somewhere.

UPDATE>>> When i turn the key i hear a fan blowing.. but the fan speed knob does not respond and does not blow when the engine is running. Not sure what to check next. Jeff

allstar said:

UPDATE>>> When i turn the key i hear a fan blowing.. but the fan speed knob does not respond and does not blow when the engine is running. Not sure what to check next. Jeff

Click to expand...

Here's a diagram of the relay box Shawn was talking about:



those square black "fuses" are actually relays, and since they have 3 rather large pins they can be a bit stubborn to remove. but they definitely do come out!

allstar said:

UPDATE>>> When i turn the key i hear a fan blowing.. but the fan speed knob does not respond and does not blow when the engine is running. Not sure what to check next. Jeff

Click to expand...

A fan? Which fan? The aspirator fan or the heater fan? Did you confirm that you are getting 12 v on the blue / red wire to the heater blower motor? If you have 12 v on that wire, then both the blower fuse and the blower relay are OK. Did you run the CCU through its self-test and confirm that it passes those tests?

OLD GUY, Where do i access the 12 v blue/red wire to the heater motor ? Jeff

The blower housing is mounted on the front bulkhead just behind the spare tire. It is a circular black plastic piece that is about 12 " long and perhaps 10 -12 " in diameter. There are three electrical connectors coming out of the blower housing and they all terminate in a vertical row below the A relay box. I think the blower motor terminator is the middle one; however, you can trace the wire back to be sure. The blower motor is mounted on the driver side end of the blower housing. Should be relatively easy to trace the wire from the blower motor back to the terminator.

When you pull the connector apart, you are checking for voltage on the 'car' side of the termination. There definitely won't be anything on the motor side of the termination.

allstar said:

UPDATE>>> When i turn the key i hear a fan blowing.. but the fan speed knob does not respond and does not blow when the engine is running. Not sure what to check next. Jeff

Click to expand...

Is the ccu dark?

My problem turned out to be a bad blower motor. $418.00 later and all is well. jeff

My A/C blower started cutting out when I was in Palm Springs for NSXPO. Talk about bad timing with temps there about 100, it was NOT GOOD having no AC. It turned out to be the blower motor relay. This relay needs to have contact for the motor to run at either variable or hi speed. Of course the relays are not identified, so it took awhile to figure out which one was it. The relay box lay out in my 1992 car doesn't match the drawing shown previously.

Thanks for the feedback on this.
The issue on my 1991 is that I have no heat.
blower works, ccu (that's the control unit for the heater-A/C right? ) is lit and I can change modes, adjust the fan, and adjust the temperature. Turning the temp down to 60 and turning the A/C on also seems to work but I get no heat when I turn the temp to 90.
I'll use the chart above to troubleshoot but I'd really appreciate any tips to help guide me to the solution.

Thanks very much!
-Randy

Are you sure the modes are switching?


No heat can be a ccu issue or a cable adjustment issue or a air bubble in the heater core.

My fan was intermittently stopping/starting. It was the relay.

BrianK, Thank you for the quick response to my earlier post!
I finally got a chance to spend a little time with my car today..
The modes DO change, except DEFROST. I can't seem to get any air output at the windshield. The rest of the settings work as expected.
The fan speed also changes as expected.
The AC appears to work (I can also hear the compressor engage) but I get no heat regardless of where the temperature is set.
I did get a foul odor out of the vents when I first turned it on but it's been sitting for way too long too.
Any thoughts or suggestions?

Thank you!
-Randy

If the modes are working your will get air to the windshield, changes on the display do not mean the dampers are moving. I normally see mode and mix (heat) problems together. I would say you are due for a CCU rebuild.

Good Morning Briank,
I''m hoping to have time to work on the NSX very soon.
Can you please give me more information on the cost of the replacement CCU and the steps to replace that?

Btw, the Bose Amp you fixed for me years ago is still going strong!
Thank you very much!

-Randy

Another VERY happy Briank customer.
The NSX is back together and now has heat, A/C and air coming out of the defroster!
THANK YOU Briank!!

-Randy

Blower Motor Relay location

Where do i find the blower motor relay? I have the same issue here in Western Australia. Over 38 degrees Celsius for over a week now and the aircon stops working?

Oldduffer said:

My A/C blower started cutting out when I was in Palm Springs for NSXPO. Talk about bad timing with temps there about 100, it was NOT GOOD having no AC. It turned out to be the blower motor relay. This relay needs to have contact for the motor to run at either variable or hi speed. Of course the relays are not identified, so it took awhile to figure out which one was it. The relay box lay out in my 1992 car doesn't match the drawing shown previously.

Click to expand...

Eddiep said:

Where do i find the blower motor relay? I have the same issue here in Western Australia. Over 38 degrees Celsius for over a week now and the aircon stops working?

Click to expand...

Check back in this thread to post #7 to find a picture showing the location of the blower relay in relay box B. Relay box B is mounted in the front hood area.