possible electrical problem?

RobsRR · Jun 3, 2019

I have a 71 RoadRunner and have added ac using mostly origanal parts. a/c controller, under dash blower box from a 73, vents ect. Using a Sanden compressor r134a. Works great but my wires to the fan blower motor switch get hot. Anyone else experience this? Blower works good conections are tight.

Sixpactogo · Jun 3, 2019

Over time these motors get dirty and dried up and the grease gets hard. When that happens, it takes a lot of current flow to run the motor especially on high speed. That is more the cause of the wires getting hot than bad connections. Although dirty and loose connections can do the same kind of damage. I'm guessing if you 71 RR blower motor has not had any attention in 48 years, that would be the first order of business for me. If you don't trust your own ability to clean and lube it, take it to a shop that does that for a living. I'm sure it is not running at the rpms it should be on any speed.

dryheat · Jun 3, 2019

if your wires fan wires are getting hot it may be due to load. Borrow or buy an amp clamp a see what the current draw is for your fan.

RobsRR · Jun 3, 2019

Thank you I will check out the above suggestions. Does anyone know what the blower motor should draw?

Sixpactogo · Jun 3, 2019

Just a guess but I would think your A/C circuit should be fused at 30A but the load should be less than 80% so if it is drawing much over 20A on high speed, it is too much in my opinion. If your #12 wires are getting hot with good connections, you are probably using more than that. If you are blowing fuses, you are probably getting up to and possibly over 30 Amps. I'm not sure how much cushion they build into these circuits but I think after I had my blower motor cleaned and lubed, it was drawing about 16 amps on high.

RobsRR · Jun 4, 2019

Good to know. I never blew a fuse just noticed wires were hot at switch.

possible electrical problem?

RobsRR

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Sixpactogo

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dryheat

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RobsRR

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Sixpactogo

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RobsRR

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