Hello,
Sorry I had to post up questions.. but ive done lots of searching and all i can find is the opposite of my problem where speeds 1 2 3 dont work and 4 does work. Well my 123 are fine but speed 4 doesnt work. Where should I start? I already pulled it out of the dash, which blows, no pun intended, as you all know. Do I do it for no reason, because thats what I like to hear!

both 15A fuses, near the steering wheel, are fine btw

look for a high blower relay.

do ya happen to know where on the vehicle it might be located so i can test it?

I'm starting to think its the switch, does anyone know a way to test it?

with a meter.
if there is continuity across it the switch is fine.

lol i got that.

problem is the switch is buried within the heat/air control dash unit and I don't know which of the electrical pins on the back to be checking out.

What is the relay you mentioned before?

I'm not 100% sure the 3rd gen has one, but on most cars the high speed is controlled by a relay that lets full voltage come through.
I would recommend getting a copy of the FSM, it is covered in there.

maximusve92 helped me out with mine i had the exact opposite i had 2,3,& 4 but did'nt have #1 its a blower relay located behind the glove box

it was the dashboard ac/heater control unit. switch number 4's electrical contact pad was completely burned up. off to the pick and pull

I went to use my ac and my switch was stuck. I tried to carefully switch from 1 to 4 and now it's toast.
I have a 2000 Maxima. How much for new a switch?

There's a relay on the right side of the passenger footwell. I think it controls the 3 and 4 speeds. However, I am currently having the exact same problem as you are, and this 'high-speed' (I think) relay as well as both fuses are fine. So I recently ordered a control unit ($118.00) from RockAuto.com. Actually I was hoping to get some feedback here as to how best to replace this, but I'll have to jump in and do it tomorrow. (I'm not sure how much dash has to be removed). I guess you'll know after pulling the one out of the wrecking yard. I'm most worried about the two cables connecting heater and vent adjustors behind the dash.


Any suggestions would be appreciated.

While I commend you for searching, you need to look at the dates of when things were posted. This thread is from 2007 - SEVEN years old. These guys are long gone.

Sorry to say that I can't help you, though.

I'm having the same problem. 1,2, and 3 work fine, 4 doesn't. I found what I thought was the high blower relay in the passengers side kick panel, and tried to test it. I keep getting continiutiy. I then tried to turn on the air/heat and it no longer worked. I have a a 90 se. I am going to put that relay back in. Is there something else that could cause this? Is it a different relay than the one that I pulled?

If it was the ballast reisistor it would be on full speed all the time!

Read post # 10 above. That sounds like your problem.