Perplexed about my 2008 Armada (SE) HVAC blower motor resistor

[robokop]

I have a couple related questions that I’m hoping someone with experience can help me with.

My main issue with my Armada is that some component is out that won’t let me operate any of my radio controls or my front climate system controls. The screen of the radio boots up when I start the vehicle, shows the Nissan start screen but then it just goes to the last screen it was on before the issue started. The blower is always running when the vehicle is on and I can’t change the speed or temperature. The strange thing is that a couple times everything started working for a while and then it craps out again. It’s been out now for several months. I’ve read multiple things on various forums about the same issue but no one seems to have a straight answer on which component needs to be replaced (even though this seems to be a pretty common problem). So, my first question is just that…what is causing this and what do I replace to fix it?

One person said to replace something called the “AV Control Unit” which the diagram looks like it is behind the two 12 volt (cigarette lighter) outlets below the stereo and climate controls. I have no idea what part number that would be and trying to do more research on it hasn’t produced much that helps me. A couple other people said to check the 20A fuse under the hood on the passenger side for the radio. I looked at my fuse and it’s not blown or overly dirty.

Secondly, multiple people have talked about replacing the HVAC blower motor resistor which should be an easy thing to do from what I’ve seen. I don’t really think that will solve my above issue since that resistor is just supposed to control the fan speed but it’s a cheap part so I figured “why not?” I pulled the resistor from under my dash to make sure I ordered the right part. My problem is that the one that was in my Armada doesn’t match the one ALL the sites I check tell me to buy. Mine has 5 fins and clearly shows the part number is VP5NEH-19E624-AA (see images below). The one on Amazon, eBay, and other sites pull up only has 4 fins and looks shorter. When I look up part number VP5NEH-19E624-AA it says it is for a 2010-2015 Armada. Mine is a 2008 SE model. So, my second question is…do I replace it with the part every site recommends or with the one that was in my vehicle? When I bought this vehicle the tires that were on it didn’t match the size listed on my sticker in the driver’s door so I wouldn’t put it past the previous owner putting another wrong part in it.

Any help with these issue would be greatly appreciated. Thanks.


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[VStar650CL]

I answered you in that other forum, so I'll just echo the conversation here for those interested:

The likely culprit for your settings not displaying is the A/C Auto Amp, which is a separate box attached to the back of the display. It's unlikely the AV Unit is responsible since your other display and radio functions work. The Auto Amp has its own fuse, #8 in the cabin fusebox, so make sure that's good. If the Auto Amp is bad or offline, it's possible that's causing the blower to run all the time, so I'd address that before assuming the VBC (resistor) is bad.

If the VBC is bad, don't sweat the number of fins on the replacement. Different manufacturers use different heat sinks, but it won't affect operation. Your existing one doesn't appear to be OE, so someone probably changed it one or more times already. When they melt short-circuit it's almost always because the blower motor is sucking too much startup current, so if that's the case, you should replace both the motor and VBC.

First of all, thank you so much for the response and help!

Does the A/C auto amp look like the pics below? I guess it’s the same thing as the “temperature control module” since that is also what the sellers are calling it. I found this one on eBay but I’m not sure if it’s the right part. Also, you mentioned that it’s unlikely the AV unit is responsible since my “other display and radio functions work” but I just want to clarify…the radio screen comes on but NONE of the buttons for the radio or climate control work currently work. I can’t change stations, I can’t change the temperature of the air coming out of the vents, etc. It’s weird to me that the radio and climate systems are connected like that but oh well. I’m not sure about buying a used replacement for it but short of going to a dealer and paying a fortune this is mostly what comes up online.

For the VBC I’m glad it doesn’t really matter if I replace it with one with the 4 fins. I never know with this vehicle what parts actually go to it or not sometimes from some of the things I’ve come across. I’ll try the A/C auto amp first and hopefully that fixes my main issue.

Thanks again for the info. It just seems so difficult to find a straight answer for certain issues like this.

That's the right type of unit. The 27500-ZQ00A on the label is the Nissan part number. You should make sure it's a match for your ride, there are usually several variants for any given model year. I suggest going to NissanPartsDeal.com and plug in your VIN, NPD has the same dbase as Nissan DPiC and you'll get the right p/n for your specific vehicle plus the number for any supersession. You should always use Nissan part numbers when googling parts for your ride, especially electronic parts. Shopping by make-model-year is just about guaranteed to give you a headache.

BUT, If none of your buttons are responding then it changes things. It's possible the front switch panel has gone bad, and yes, the AV Unit also. The way the controls work on an early Armada, the A/C switch panel has its own "brain" and talks to the AV Unit on a LIN line, the AV then passes the info to the Auto Amp via the CANbus. If the Auto Amp needs a change in the display, it then sends a command back to the AV, which is in charge of the display. So any one of the three could be responsible for your A/C problem. Given what you say about it not responding to radio buttons, I'd be inclined to suspect the AV or the switch panel. Check all your fuses with a test lamp, not a visual inspection, including any fuses marked "audio" in the Fuse & Relay Box under the hood. There are multiple fuses which feed the AV and Auto Amp.

[VStar650CL]

PS - This website has the complete FSM for your ride, with wiring diagrams and explanations. The HVAC Control section (HAC) is here:
https://www.nicoclub.com/service-manual ... %2Fhac.pdf