Burned wire - find the cause before fixing?
 

I found a burned wire on my AC fan switch in the center console. I've got a replacement switch on the way but do I need to identify the cause before I replace and repair?

Attachment 10639

Yes unless you want your new switch or worse yet your whole car to go up in flames.Your fan motor is probably on its way out start there

Corrosion of terminals for the red (power source from battery) and red/white (full speed direct to evap motor) may also be responsible for this. It induces some contact resistance, which heats up and cook the wires. Mainly when the highest current runs thru these wires. That is why they are the only two to be damaged.
So yes you should check your evap motor in case it is shot (but the 25A fuse should have blown), but replacing the switch may be all you need to do.

Loose connections are hot connections.

this is regular problem with these a/c switches..They get too hot are NLA nowadays they are made from plastic.As John W. said most likely loose connection on the switch-have seen that many times.
Providing your other el. units are working properly.

Ivan

The burn pattern looks like the heat originated in the switch. If the actual switch contact degrades it could become more resistive and thus dissipate power (I x I x R). With power comes heat. Check the wire on the fan. If the fan wires are ok, then just replace the switch.

You may want to repair the wire by either replacing the entire wire or just the connector and a bit of wire. Inspect the wire and connector for integrity and replace what appears to be damaged by the heat.

Both John and Pro are correct, It's a fair amount of current going through a connector thats less than adequate when aged. Cut the wires back to the good insulation, the copper wire should look like new there, crimp on some new connectors with heat shrink, install the new plastic switch, MAKE SURE that your car has an updated A/C fan relay in the smugglers box, the style with a fuse, and your good to go!

M

Thanks for the input!

I was wondering if the switch itself was the cause. I will definitely be repairing the wiring but will also check out the fan itself. I've always wondered why the highest speed never worked...

One day I want to upgrade to a Griffith's system but that's a future project ($$$)

There is a switch sold by all points bus that is a like for like replacement of the original, rather than the new plastic OEM model.

Attachment 10640