AC Control wires hot/melting plastic behind dash

I have a 2011 DCSB and about 2 months ago the AC control lights were not working right. You could tap the controls and the lights would come on/off. A few weeks later the high speed would only blow in low.

I replaced the blower motor resistor with a new one and high works now the lights still don't work correctly. But there is another issue and it's a big one.

Here is the problem. The wires running into the back of the controls are so hot it's actually melting the plastic under my dash. I thought the controls were bad so I replaced them with another set out of an 09. The AC works but you have to put it on hot to get cold, cold does hot. Not a big deal but the wires after 2 minutes of running were so hot you could barley touch them. The back of the control panel is also extremely hot. There is actually parts of my dash behind the controls that are melted from the wires touching it.

There is burn damage to the plug and the two wires that get hot are the white ones only. White/black strip and white/blue strip. The pic is bad but you can see how discolored the wires are from it getting hot.

The plug to the resistor is fine and doesn't seem to get hot when I run it but I need to test it again.

I haven't had a chance to check pull the HU out and look behind it as I was thinking this could be a bad ground. I've just never had to tackle something like this before and could use some assistance on where to start or what the hell is causing this?




Old resistor on right, new on left.

 

First thought is the Blower Motor itself. On other vehicles, the resistor going out is usually caused by the blower motor going out.

 

That's what I'm thinking as well after reading about it more. Going to order one and I think I'll stay away from the TYC one. Think I'll order the Delphi or just OEM.

I'm thinking I should cut out that burnt section of the wire and replace it as well.

 

I agree, probably chase your tail with parts if you don't.

 

See the second picture above. The burned area at the terminal clip inside of the connector. It is loose fitting onto the terminal in the AC Controller. This looseness is acting like a heater. All a heater element is wire with resistance. So when the clip is loose onto the terminal it adds resistance to current flow and heating.

What you need is a new connector that has tight fitting terminal clips. If you don't it will continue to burn. Note: I am an electronics tech and work with these automotive connectors every day.

 

Appears similar to the blower fan resistor connector problem:

https://www.tacomaworld.com/threads/before-you-replace-the-blower-resistor.107093

 

Thanks. I ordered the harness from Toyota. I also got a new blower motor just to be safe. Everything should be here Tuesday and I'll know how it goes then.

 

That should do the trick.

 

my ac connector on my 2013 is burnt too. and now the ac doesnt work on the high setting. this is something i should prob take care of

 

Geez. Not good.

 

I ended up adding solider to the main power wire pin. It was a loose connection and causing high to not work.

What part of AZ are you in? I can help you fix this before it gets worse.

 

That would be way freaking cool Aw9d. Mesa, wbu?

 

I'm in Chandler. Send me a PM. This weekend isn't good for me but I could help out after work or the following weekend. Send me a PM and we'll figure out a time to try an fix it

 

I had that problem in 2015.. bought the control head.. I think it cost like $100 for the control head from LKQ and the guys at Toyota gave me the pigtail.. I hooked it together and for some reason my control knob when on cool blew hot air and hot air blows cold. It WORKS!! Just recently replaced my resister, pigtail and blower Monday as well.. so it should hold up

 

You have a 2005 truck with a newer control panel. Not sure what year off the top of my head but the wires for hot and cold were swapped in the harness. Someone on the forum posted about swapping in a newer panel and it was mentioned which wires to swap. Search may find the post.

Wiring Diagram: https://www.tacomaworld.com/attachments/2012-climate-control-pdf.1149215/


This post # 15: https://www.tacomaworld.com/threads/2012-climate-control-in-2011-and-under-tacoma.259754/

And

https://www.tacomaworld.com/threads/12-15-climate-control-in-a-05-11-truck-wiring-guide.411534/

 

Did you ever get the lights working properly?

 

Yes once I put new bulbs in problem was solved. I had to fix the connector first.

 

Ahhh. There u are aw9d. Pm coming

 

What is the part number for the electrical connector that snaps into the back of the heater control? Mine is melted as well as my heater control. Heater control is on order but cant find the plug in the Toyota parts diagrams. Thanks

 

There is no part number unfortunately. You'll have to buy a new climate control and then cut the parts of the wires that are toast and make your own harness. I got lucky and found someone with a totaled tacoma and I ended up cutting their harness off and used that one. When I contacted Toyota about it they said I have to buy the entire wiring harness to replace that one clip.

What I've done to fix a few other people's that melted was use connectors and just slide the cables on one by one to the new climate control. Make sure they are tight or you can go as far as solder them to the climate control directly. I'll use quick disconnect butt connectors for each wire in case they need to remove the climate control later.

Good luck!