Frontier cabin fan fuses

Sounds like the resistor pack that drops the voltage to the motor for the lower 3 speeds is toast. Happened to my 94 Altima a year or two ago. It should be a little flat board maybe 2 or 3 inches square screwed into the blower motor housing with two screws, or at least that's where mine is. It was about $50 cdn to replace at the dealer, but it was a quick and painless swap.

Nope, no "hidden fuse" it's the blower amplifier/resistors that cause this problem. Hi speed bypasses these devices.

Thanks for the pointers to the resistor bank as the source of my problem. I took things apart today to see if I could locate the resistor bank, but didn't find it. All I found was what looked like a small circuit board with several components on it including an IC or two This was mounted on the outside of the air plenum. This board had a pair of wires going into the air plenum which connected to what appeared to be a thermocouple. From the description that you folks gave that didn't sound like the right thing.

I pulled out the fan as well, but it has only two wires connecting to it, so I know the resistor bank must be somewhere between that fan connector and the switch, but everything is totally hidden by the plenum box, which is tough to get out or around.

JM pointed to where his resistor bank was in his Altima, but I didn't find anything like that in the section of the air box plenum that I could get apart. Anyone have any specific pointers to where it may be in this truck?

Thanks, Stew

I forgot to add that it was under the dash on the passenger's side of the car (inside the cabin).. Maybe that helps?

if people only knew how to do a search first before asking questions the have been asked hundreds of times before

Ussually the newer vehicles have an electronic "blower amplifier" although some still use resistors. These are always located somewhere on the blower housing so the air created by the fan can cool them. I've never dealt with this on this model nissan so it could use something else altogether? EIther a google search or a FSM should point you to the problem.

AFAIK, the "blower amplifier" is just the resistor pack with a heat sink on the outside of it. The reason for the heatsink is that the wire wound resistors are red hot (like the cigarette lighter) and can easily ignite well shredded leaf and pine needle debris in the heater box and cause a fire (had several myself).

I've never seen a car without the resistor pack... and it is always set up in the air stream. Seems like a crude solution to control motor speed but they all use it, even the fancy ones I've seen. I'm sure he has one.

Actually some cars have infinitly variable blower controls and use a transistor -solid state- amplifier to control the fan speed. 280ZX's were like this.

Just fixed the fan problem. The resistor block is mounted under the glove box near the firewall. The block has a plug with four blue wires on it and is mounted with two screws. I recommend you replace this block to get the other speeds back. I repaired mine but still recommend replacement, cost about $50 Canadian.

Something caused the amp to go bad. It's likely that the fan motor pulled too much current and fried the amp. If you only replace the amp, it may go out again quickly. I just fixed the same problem in my Pathfinder. Before the amp went out, I did notice that my fan motor would occasionally make a strange sound when it started up. Nissan's service bulletin recommended replacing the blower motor at the same time as the amp.

Check out

Sorry to post-jack....

I don't know what you mean when you say that the AC stays on all the time, even when you go to defrost. The AC will stay on when the AC button is on and the fan speed is set, no matter what position the vents are set at, or the temperature you have set. As a matter of fact, you *DO* want the AC on when you go to defrost in some situations. i.e. At any time of the year, it's raining out and you get wet getting to your vehicle. You get in and within a couple of seconds, your windshield and windows suddenly fog up. You could start the vehicle and set the heater to heat, place the lever in the defrost setting, and then you wait... and wait... and wait, until the engine warms up and warm air starts defogging the windshield slowly from the bottom up. Good luck on the side windows though, you'll probably be home before they clear. Or, after getting in the car, you turn on the AC, set the lever to defrost, outside air, and set the heat control to warm. Within seconds, the windshield, and the side windows, will clear up from the cold, dry, AC air, and you can immediately drive away. Leave it in this position until the defroster air becomes warm and then turn off the AC button and adjust the heat to where it is comfortable.

You are correct about those times when you *do* want the A/C on. However, with Frontiers, Nissan chose to have the A/C activated when the selector is put on defrost, and the A/C doesn't turn off until the truck itself is turned off, no matter if you turn the selector to panel, feet, etc. That means that, sure, use the defrost when you first start up the truck, but do you still want it running the whole way to work, after you've no longer needed it?

On my wife's Toyota, the A/C turns on with the defrost, but then turns off when you select another position, like panel, etc. I can't understand why Nissan resorted to the lazy way out. Of course, I can now turn the A/C on and off in the defrost position any time I want, which saves gas, etc....

Anyways, just my $.02...

It is supposed to also reset if you turn the fan off. Mine used to work that way and then it just stayed on all the time ANYTIME the fan was on. I finally disabled the microswitch that senses when it is turned to defrost and it has worked great ever since - It now only turns the compressor on when the A/C button is pressed. The switch is a normally closed switch that was stuck open, so I had to cut the wires from the switch and connect them together. I was able to do this by taking out the glovebox.

That means that, sure, use the defrost when you first start up the

The problem is, it doesn't reset when the switch turns the fan speed off. That's why I disconnected the microswitch, too...

Yeah, I don't know why Nissan spent all that money to add that microswitch. It must be lawyer related.