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TR6 TR6 Blower switch

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bcbennett

bcbennett

Senior Member
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Hi all,

Just replaced my '74 TR6 heater unit with one that is rebuilt and ready. The previous owner had all the leads from the switch disconnected, and now, when I try connecting various combinations of the three wires (one hot, one low-speed, one high-speed), my fuse keeps blowing. I see two side-by-side connectors above the two vertical connectors, and I assume the hot wire goes to one of the upper prongs. Am I right? Help!

CB
 
Do yo u have the wiring diagram for that year. Shows the connections

74Heaterconnection.png
 
Yeah, Don, that's the first place I went, but that diagram doesn't help me much as I look at the switch. Granted, I am no electrician, but I have used the diagrams in the past to figure things out.
 
First of all, are you sure you have the right switch ? There are different switches that look almost identical, differ only in contact configuration; and ebay sellers don't always know (or care) what they are selling.

Second, if you are blowing fuses, I would suspect something other than switch wiring; as connecting any combination of those 3 wires together should not blow the fuse, and the switch should have no internal connection to ground.

If you look closely, the switch has numbers cast into the bakelite to identify the terminals, and those numbers match those given in the wiring diagram.

But I would want to first buzz out the switch to be sure it's working properly (they're tricky to assemble properly); and maybe make sure the blower works with the wires connected directly together rather than through the switch.

In case you don't have the diagram (and can't read Don's image ... I sure can't!), the green wire brings power from the fuse to terminal 4; the green/yellow wire gets low-speed power from terminal 6; and the green/brown gets high-speed power from terminal 8.
 
I found that my heater switch worked fine until I installed it and pulled it on. At that point one or more of the unused terminals would ground on the metal in the mounting hole and *PFFFT!*- blown fuse. I solved the problem by covering any unused terminals with electic tape. So far, so good. I'm not sure why my switch has extra terminals.
 
Success!!!

You guys are golden. My switch was installed upside down to the diagrams (but the knob fits that way--weird) and when I taped up the spare prongs, hooked up the wires correctly, and crossed my fingers--wham. Works perfectly.

Now I can drive around in the triple-digit Abilene summers with my heater on!!
 
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