#1  
Old 01-23-2022, 06:00 PM
Jonsie Jonsie is offline
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Location: Punta Gorda FL
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Default Rear Defog wiring problem

'65 Catalina, wiring going to the defog motor is heating up. There are 2 wires spliced down to one halfway between the switch and fan motor. I am guessing the one wire (appears to be braided) acts as a resistor wire for low speed operation? This wire is heating up, enough to start melting the factory electrical tape. I caught it in time to get it disconnected from power. I hooked up the circuit on the bench, fan motor and switch are normal temps while the wire is heating up. Remedy as easy as ordering a new length of wiring from the switch on back? This wire is original 55+ yrs. old. Any help is appreciated..........

  #2  
Old 01-25-2022, 12:19 PM
Jonsie Jonsie is offline
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I tried to order a new lead from our host, sales person said there is only one wire from the switch to the fan, not two. Don't understand how the fan can have both Hi-low speeds with only the one wire. Just the regular gauge purple wire with no resistor wire. Anyone?

  #3  
Old 01-25-2022, 02:12 PM
gto4evr gto4evr is offline
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your first post was correct. the two speed operation is high being a single run wire and low by running power through the resistance wire that then comes back up through the splice, so at the end of the harness here it plugs into the motor it's only a single wire. The wire does get hot an they've got it sealed in a factory gummy tape.

when I made a new wiring harness for mine since I was missing it after gettng the rest of the parts, , I put the resistance wire in one of those fiber heat jackets to insulate it from melting anything.

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Old 01-25-2022, 05:34 PM
Jonsie Jonsie is offline
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Thanks for your reply. After bench testing the circuit, the resistor wire proceeded to get hot, enough to melt the factory wrap. This was after I pulled the bucket seat, pulled the carpet, removed the rear seat bottom, and retreived the length of wire. Maybe the resistor wire breaks down over time, I don't know. Meantime I found a new defog harness at lectric limited. Was suprised that M&H didn't carry it.

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