Resistor question

[WFarm]

Getting ready to remove and paint the LH side inner fender on my 1975 Blazer and can’t determine what this large resistor is for. Truck came from factory with air, auto and 350 engine. Figure someone here knows for sure!

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[bucket]

Getting ready to remove and paint the LH side inner fender on my 1975 Blazer and can’t determine what this large resistor is for. Truck came from factory with air, auto and 350 engine. Figure someone here knows for sure!

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I believe that is the trailer brake power adjustment for an ancient brake setup. You could move that slider doohicky along the spring wire doohickys to adjust the amount of resistance. I've seen them, but never used them.

 

[WFarm]

@bucket based on your lead I did a search for Vintage GMC electric brake resistor. BINGO! Mine is from a different manufacturer and not marked so obviously.

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Not needed but looks cool, like something from Dr. Frankenstein’s laboratory. Might detail it and keep.

 

[DoubleDingo]

Dr. Frankenstein doohicky

 

[squaredeal91]

Getting ready to remove and paint the LH side inner fender on my 1975 Blazer and can’t determine what this large resistor is for. Truck came from factory with air, auto and 350 engine. Figure someone here knows for sure!

You must be registered for see images attach

Trailer brake?