Radio has at times alternator whine. Mainly seems to comes with electrical load. Removed radio and saw this.


Got the car back in 2015. Memory is bad. But do remember an issue with manual HVAC control box being burnt. Replaced. Not sure if burn on connector is old or recent. Think I would have seen it back then. It is Blue/white wire. The burned area was not in the fan controller side but the a/c switch.

Fan motor is new aftermarket a few years. Not sure what to look for? Or if radio issue is unrelated and this burn mark is old.... Any suggestions?

Do you have an aftermarket radio? Possibly someone burnt it with a soldering iron putting in an aftermarket radio. Radio whine is normal you can try cleaning grounds and adding ground cables, making sure radio is grounded well, and installing "filters" that remove the noise

No. This connector is for the fan switch. Could be two different issues???? I have an aftermarket radio but the whine is not constant.

If I understand the wiring for the fan the blue/white is the ground. I am not sure what causes the heat to burn the connector? Or what part is most likely cause? The fan switch, fan resistor, or fan?

I'm saying the connector probably got burnt by a soldering iron if someone was wiring in a stereo. Definitely separate issues. The noise is electrical interference you can "filter" out or you can try to fix it by grounding the radio and battery better

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Check all the connections, it's most likely a ground loop issue.

I think I may have confused folks here. My post is concerning the burnt connector for the fan switch. Something caused an awful lot of current to melt the connector. What does the fan switch do? Route the ground from the resistor?

I'll bet my car your connector plastic got burnt when someone was using a very hot soldering iron to wire in their aftermarket stereo. Burnt through a lot of plastic in my life with a soldering iron. Stepped on one once too

Your thread is about a burnt connector having something to do with a ?burnt? Manual HVAC unit replaced several years ago. and unrelated electrical interference from the alternator that they make "filters" that you can wire in to fix.

Tell us about the old "burnt" HVAC unit. Did it catch fire? Or did this connector just get melted coming into contact with the soldering iron someone was using to wire in their aftermarket stereo

Sorry. I was taking the radio out due to the whine when I found the burnt connector for the fan.

Looking at the fan connector for real the burnt mark is from heat from the fan circuit. Poor picture taking on my part. It does look like a soldering iron burn but it is not.

When I got the car the a/c relay would not work. Spent a week figuring it out. The HVAC controls were burnt on the inside. The control board was melted. I replaced the board and it fixed the issue. I think I would have noticed the burnt connector at that time. I can't remember if I changed just the control side - kepted the fan switch and my old housing and just replaced the electrical board for the HVAC controls. - I did this because I had new bulbs already installed in the original one.

Been busy with other projects. Here is a pic of the back side of the fan switch.


Could not notice when installed but there is a noticeable drag in the switch most likely when the switch rotates over the burned section. Also there is an grinding noise when rotating the switch.

I have not driven the car very far but at idle and a few short trips the radio noise is gone- the whole HVAC system is unplugged. Going to pull a part to get another switch. Then I will test the amp draw on my fan.

Still unsure of how the fan switch works. Is it just a mechanical switch- just moving parts? or does it perform some resistance as well?

It is just a simple mechanical rotary switch. It has a moveable contact that will connect with one of 4 connections (or wires). 3 of the connections go to the resistor for speeds 1, 2 and 3. The 4th contact bypasses the resistor and goes directly to the fan motor, giving you the high speed. The moveable contact is connected directly to ground and supplies ground to the other 4 contacts/wires. This switch only interacts with the blower motor and its resistor. It does not interact with any other circuits in the car.

The switch is available as a separate part. You do not have to replace the entire control panel.

Thanks. But I am still confused.



The burned spot is on L/W. On setting 1 -3 ground does not flow to L/W between the resistor and switch? On 4 it flow it flows only on L/W?

So the Or/B provides ground for the a/c switch only at 1-4?

I did go and find another fan switch than at the yard that seems to operate smoothly and no burn marks.

So most likely either my old fan or new fan on high are drawing too much current?

Installed used switch today. It got hot on 4. Suspect fan is drawing too many amps.

The bearings may be seizing up in the fan motor, which will cause the motor to pull too many amps of electrical current. Pull the fan out and see how easily it spins.

new fan with squirrel is practically free last time I needed one from rock auto .bought an extra .. problem solved. good idea to keep a sparer resister too. rock auto had those on closeout for a couple bucks last year.
it's a good idea to get on the rock auto closeout email list. .usually get a few mails a year with items the are closing out for my max and wifes versa

I tested fan amp draw on high around 18-19 amps. Does anyone know what the amp draw should be on high? There was a big jump from 3 to 4 (high). Three was around 7-8 amps.

19 is "way too many". Suggest replace fan motor.

Also - enjoy your new car...?

New fan - Depo brand. It looks cheap. Amp draw was all over the place from 17 to 18.5. It is going back to Amazon. My old OEM fan is the lowest at around 15.75 - 16. I am going to a pull a part to get one from a Pathfinder. It seems the Pathfinder uses same fan up until 2004. I will see what one of these will draw.

What is confusing me is the ground wire at the fan is cool. The only heat seems to be at the fan switch, With my cheap IR temp gun temp is over 170 F. at the back of the switch, The contacts that protrude/flush with the plastic on the back side of the switch are too hot to touch. Any thoughts?

Pathfinder fan was 14.5 amps. It was cheaper to get motor only (no blade) at the yard. When I took my blade off my old fan there was a ton of bushing dust. However, fan switch is still getting hot.