Burning smell when initially turning on ac

T

trickbiker121

New member
On my 05 4runner I have been getting this strong burning smell when I first start the ac. It will go away after a few minutes. I first noticed this after an oil change from the dealer about a month ago and I thought they might of spilled oil on the engine so I did not say anything. Now its been over a month and the smell is still there. The 4nr has 99,000 miles on it. I ordered a new engine and a in cabin filter from Amazon to see if it will get rid of the smell. What do you guys think?

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methinks something is a bit tight in the belt system,a pulley maybe, the ac compressor?...such issues usually get worse and end up with a broken belt miles out of town, on a deserted road at night :)
 
earthrealm said:
methinks something is a bit tight in the belt system,a pulley maybe, the ac compressor?...such issues usually get worse and end up with a broken belt miles out of town, on a deserted road at night :)
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You might be right. I do have the high pitch squeal for a while now. But wouldn't the smell stay if the belt is constantly tight?

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What does it smell like? I know the Tacomas had a problem with the switch melting on high. Just thinking out loud.
 
MFreund said:
What does it smell like? I know the Tacomas had a problem with the switch melting on high. Just thinking out loud.
Click to expand...
It smells like a wire burning. I should also mention that I did have my dash replaced a few months ago so the console has been opened before.
Edit: just checked the 4runner and I can't find the source of the smell under the hood or foot wells. The smell also seems to only come on a cold start. Like over night instead of on every start.
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trickbiker121 said:
It smells like a wire burning. I should also mention that I did have my dash replaced a few months ago so the console has been opened before.
Edit: just checked the 4runner and I can't find the source of the smell under the hood or foot wells. The smell also seems to only come on a cold start. Like over night instead of on every start.
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Click to expand...


I think I would pull out the fan switch and look at the connection for dark colors or burnt marks.
 
MFreund said:
I think I would pull out the fan switch and look at the connection for dark colors or burnt marks.
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Where is the fan switch? I opened the passenger foot well under the glove box and all I saw was the TPMS module and 4WD control box.

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I just saw you're from Louisiana. What part? I'm from east baton rouge parish..town called Zachary, just outside of Baton Rouge.

You could:
A) remove the belt and spin each pulley by hand in order to rule out any of the pulley's bearing failure. The pulleys should spin smoothly. If one spins 'rough' you will be able to tell and can start your repair process from there. I'm not sure of your mechanical skill level but the procedure to change a belt isn't very difficult imo.

OR

B) maybe your belt just needs to be tightened. Be careful because over tightening a belt can lead to problems too.

Another thing, if you let the belt squeal too much, the belt will become glazed, which could ruin your belt.
 
The A/C motor is about to burn out I guarantee it. This same thing happened to my '05 Mitsubishi Endeavor never really paid much attention to the plastic burning smell until the fan went in and out on the
A/C full blast. Then when I brought it to the family mechanic, he showed me the wire connection was shorting out and burning the plastic.
TLDR: Check your A/C motor


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So I received the Engine and in cabin filters today and took some pictures while replacing them. The burnt smell has gone down and is not as noticeable as before but still there when smelling closely.
MFreund said:
Open the door under the switches and remove a q0mm bolt then pull out switches.
Click to expand...

This bolt under the fuse panel?
<a data-flickr-embed="true" href="https://www.flickr.com/photos/47979502@N04/27671637925/in/dateposted-public/" title="IMG_20160614_105457"><img src="https://c6.staticflickr.com/8/7496/27671637925_c9ef87d2f1_b.jpg" width="766" height="1024" alt="IMG_20160614_105457"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>
4runovertexas said:
The A/C motor is about to burn out I guarantee it. This same thing happened to my '05 Mitsubishi Endeavor never really paid much attention to the plastic burning smell until the fan went in and out on the
A/C full blast. Then when I brought it to the family mechanic, he showed me the wire connection was shorting out and burning the plastic.
TLDR: Check your A/C motor


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Click to expand...

I checked the AC Blower and some wires around it and saw no signs of burns. Here are some pics.
<a data-flickr-embed="true" href="https://www.flickr.com/photos/47979502@N04/27671728235/in/dateposted-public/" title="IMG_20160614_111033"><img src="https://c4.staticflickr.com/8/7430/27671728235_d7847bb850_b.jpg" width="766" height="1024" alt="IMG_20160614_111033"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>
<a data-flickr-embed="true" href="https://www.flickr.com/photos/47979502@N04/27597146801/in/dateposted-public/" title="IMG_20160614_111016"><img src="https://c2.staticflickr.com/8/7423/27597146801_0140cceb13_b.jpg" width="1024" height="766" alt="IMG_20160614_111016"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>
<a data-flickr-embed="true" href="https://www.flickr.com/photos/47979502@N04/27671729735/in/dateposted-public/" title="IMG_20160614_111006"><img src="https://c8.staticflickr.com/8/7276/27671729735_a435af7f22_b.jpg" width="766" height="1024" alt="IMG_20160614_111006"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>
<a data-flickr-embed="true" href="https://www.flickr.com/photos/47979502@N04/27671730645/in/dateposted-public/" title="IMG_20160614_110921"><img src="https://c6.staticflickr.com/8/7379/27671730645_489bfbb252_b.jpg" width="766" height="1024" alt="IMG_20160614_110921"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>
<a data-flickr-embed="true" href="https://www.flickr.com/photos/47979502@N04/27671731735/in/dateposted-public/" title="IMG_20160614_110227"><img src="https://c8.staticflickr.com/8/7079/27671731735_fa9d58d879_b.jpg" width="766" height="1024" alt="IMG_20160614_110227"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>
<a data-flickr-embed="true" href="https://www.flickr.com/photos/47979502@N04/27671732205/in/dateposted-public/" title="IMG_20160614_110035"><img src="https://c6.staticflickr.com/8/7559/27671732205_87f5309da7_b.jpg" width="1024" height="766" alt="IMG_20160614_110035"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>
<a data-flickr-embed="true" href="https://www.flickr.com/photos/47979502@N04/27597150671/in/dateposted-public/" title="IMG_20160614_110009"><img src="https://c8.staticflickr.com/8/7335/27597150671_749be0948a_b.jpg" width="1024" height="766" alt="IMG_20160614_110009"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>

I also did notice that one of the pulley on the serpentine belt is wobbling. Anyone know what this pulley does?

<a data-flickr-embed="true" href="https://www.flickr.com/photos/47979502@N04/27597145451/in/dateposted-public/" title="VID_20160614_112158"><img src="https://c4.staticflickr.com/8/7765/27597145451_1137fe67d3_b.jpg" width="1024" height="576" alt="VID_20160614_112158"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>
 
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trickbiker121 said:
On my 05 4runner I have been getting this strong burning smell when I first start the ac. It will go away after a few minutes. I first noticed this after an oil change from the dealer about a month ago and I thought they might of spilled oil on the engine so I did not say anything. Now its been over a month and the smell is still there. The 4nr has 99,000 miles on it. I ordered a new engine and a in cabin filter from Amazon to see if it will get rid of the smell. What do you guys think?

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Click to expand...
Did you ever resolve the issue? My 08 Just started doing the same thing. Wicked smell on startup. Seems to dissipate after driving a while. But now my a/c seems to not blow as cold. My regular mechanic couldn’t figure it out. Said belt and pulleys all look fine.
 
Second this, my 07 started this a couple months back. AC smell happens after cold start and dissipates after a min of driving. Checked the resistor and fan operates at all levels. Even bought an OEM blower motor and replaced that, still smells, cabin air replaced as well.

I did notice that my car doesn’t have to be running to smell it, so it can’t be the compressor or belt. That’s why I thought it might be the blower motor, but it’s obviously not.

Any help is really appreciated, spent so much time researching and can’t figure it out for the life of me.
 
Not sure what to tell everyone here that hasn't already been mentioned except that no one has mention to pull the AC control panel and check for burnt wires, connectors and inspect the circuit board as well as possibly disasembling the switches to check the contacts, to start use your eyes but also your nose and smell different areas of the control panel, if anything is shorting out on the panel the burnt smell should still be present in the area of the issue.
 
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The dealer replaced the Serpentine belt due to wear and their was a leak in the AC condenser, both were replaced by dealer at the same time. I believe it was the AC condenser because when I took it in the AC was blowing hot air. Anyone experiencing this issue most likely it is a sign the condenser is about to fail.

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